Sky Wonders

Mars Opposition 2005

2005-10-29T15:15:00.000-05:00

Hi Skywonderers!

Getting ready for Halloween? Well it looks like the Great Pumpkin really is coming this time!

This weekend Mars will come closer to Earth than it will again for another 13 years. Mars will be as close about 43 million miles away on October 30th, 2005, just in time for Halloween.

Whenever an outer planet, one that is further from the Sun than earth, is opposite the Sun as viewed from earth, it is said to be "in opposition" which is a time when that planet is really close to earth.

Mars is in opposition with earth every 26 months, or roughly every two years. The last opposition, on August 27th 2003, was truly a historic one with Mars being only 35 million miles from earth. Mars will not be this close to earth again until August 28th, 2287!

Learn more about Mars opposition from the NASA Mars Exploration Page.

Mars will be easy to spot in the sky this year, as it is very large and bright and has an orange "pumpkin" color to it! This "Great Pumpkin" will rise in the east just after sunset, travel across sky all night long, then set just before sunrise for many nights near Halloween this year!

Yes, the closest technically is on October 30th, but we can't help but celebrate the Great Pumpkin's arrival finally!

Trick or Treat!

Dan

See the Shuttle and ISS From Your Backyard!

2005-08-04T23:00:00.000-05:00

Want to see the Space Shuttle Discovery undocking from the International Space Station from your own backyard?

Currently the shuttle is docked to the ISS, but it is planning to undock and separate the space station early Sunday morning, August 7th.

Within several hours of this separation people in central Texas (YOU AUSTIN), south Florida and Louisiana will be able to see two starlike objects, the shuttle and ISS, travelling across the early morning sky!

See the NASA Science Space article here: http://science.nasa.gov/headlines/y2005/04aug_sightings.htm?list133024

To find the space shuttle and other objects in the sky above your location, vist the Heaven's-Above website at: http://www.heavens-above.com.

Good Night!

Dan

Subscribe to SkyWonders.com Email List!

2005-08-01T08:34:00.000-05:00

Want to know when an update has been made to SkyWonders.com? Subscribe to the email list by sending an email to:

skywonders_owner@skywonders.com

with the subject "subscribe" and it's done!

Dan

More on the 10th planet discovery

2005-07-30T16:15:00.000-05:00

A newer, better article related to this weeks' 10th planet discovery by CalTech astronomers was published on Sky and Telescope's website yesterday: http://skyandtelescope.com/news/article_1560_1.asp

When I first heard this news yesterday I initially didn't think much of it since :

1) Astronomers have already found a few large Kuiper Belt objects (objects in the ring of debris at the very outskirts of our Solar System)
2) Astronomers keep finding extra-solar planets (outside of our solar system)

But this new discovery is different than those discoveries because it is bigger than Pluto, making it more likely to receive official planetary status by the International Astronomical Union, the international body that decides the names of planets among other things. The planet's name is still waiting a response from the IAU, but is known informally as "Lila" by its discoverers. Mike Brown, one of the discoverers, says as much on his website: 2003UB313 Discovery page

Incidentally, 2003 EB313 (Lila) was officially discovered A DAY AFTER another large Kuiper Belt Object (KPO) that was officially discovered by astronomers in Spain: http://www.iaa.es/%7Eortiz/brighttno.html. This object, officially called 2003 EL61, has not received as much press as Lila, because it was smaller than Pluto.

The CalTech astronomers who discovered Lila technically also found 2003 EL61 (they called it Santa) in their data BEFORE it was discovered by the Spanish astronomers but waited too long to publish their discovery and so did not get the official discovery credit: Mike Brown's 2003 EL61 Discovery page.

So how do all the Kuiper Belt Objects discovered thus far stack up in size?

These images may help:

Good Night!

Dan

Remember Columbia: NASA Returns To Space

2005-07-10T22:30:00.000-05:00

In 3 days the shuttle Discovery will lift off from launch pad 39-B at Cape Kennedy, signifying NASA's return to space after a more than a 2 year hiatus after the Columbia tragedy of February 1, 2003.

As part of remembering that tragedy, I thought I would share a really great article entitled The Problem With Houston that eloquently describes the events that led to the disaster.

Although this article was initially published in Atlantic Monthly, it can be found online in two parts on the Guardian Unlimited website here:

Part 1: http://www.guardian.co.uk/columbia/story/0,12845,1120962,00.html
Part 2: http://observer.guardian.co.uk/magazine/story/0,11913,1119849,00.html

I strongly encourage you to read the above article as it details the failure of the NASA bureacracy to react to the concerns of a team of low-level engineers to the video of a large piece of foam hitting the left wing of Columbia on takeoff. It is a good illustration into the effect of organizational culture on good engineering judgement and analysis. It is now known that the foam could have caused a 16-inch hole in the leading edge tiles of Columbia's left wing.

Results from investigation of Columbia tragedy: http://www.npr.org/news/specials/shuttle/

Pictures of Columbia disaster: http://www.guardian.co.uk/gall/0,8542,888237,00.html

See complete coverage online of the launch of Discovery on July 13, 2005 at: http://www.nasa.gov/

Good night!

Dan

Light Pollution World Atlas

2005-05-20T22:00:00.000-05:00

Are you curious as to how dark your sky is? Or where to go near you for really dark sky?

In 2000, ISTIL, the Light Pollution Science and Technology Institute in Italy, generated The First World Atlas of the zenith artificial night sky brightness at sea level. This atlas was generated using satellite data and modeling of light propogation in the atmosphere.

The technique used to generate this Light Pollution World Atlas is detailed in a paper written in the Monthly Notices of the Royal Astronomical Society. By comparing this Atlas to detailed population density maps, the paper reveals that 2/3 of the world's population and 99% of the US population (excluding Hawaii and Alaska) and 99% of the European Union's population live in light polluted skies. In addition, 20% of the world's populatoin, 67% of that of the US and 50% of that of the EU can no longer can see the Milky Way.

Those are tragic statistics indeed.

Here is the Light Pollution World Atlas :

Notice how the US, the EU and Japan are the biggest light pollution offenders, which by no coincidence are the most industrialized regions of the world.

The World Atlas is available at the ISTIL website as a 200MB TIFF image that you can then use to zoom in to your particular area of the world.

Someone has done this already for Texas: http://personalpages.utsi.com/~kgl/Texas_LP_Maps.html

The colors in the light pollution maps correspond to the ratio between artificial sky brightness and the natural sky brightness of:

Black <0.01
Dark Gray 0.01 - 0.11
Blue 0.11 - 0.33
Green 0.33 - 1
Yellow 1 - 3
Orange 3 - 9
Red 9 - 27
White > 27

Don't get discouraged, however, as I happen to live at the edge between red and orange and still am able to see lots of stars, although every year it gets worse.

One thing to note is that this map is for ZENITH light pollution, meaning straight up from where you are. If you have a large city to the North (as I do), then your Northern skies will be significantly less than your zenith value.

If you're looking for dark skies, you'll have to consider how dark you really want it. And even if the area you choose is considered Dark Gray, be sure you don' t have any White areas too close or you will lose that part of your non-zenith sky.

Good (dark and clear) night!

Mars Lander Found??

2005-05-06T13:08:00.000-05:00

It is possible that the Mars Polar Lander has been finally found?

It appears that upon reexamining images taken in 1999 and 2000 from the Mars Orbital Camera aboard the Mars Global Surveyor, planetary scientist Michael Malin may have discovered what appears to be impact marks and the deployed parachute from the MPL spacecraft lost in December 1999.

Here are the complete articles from the web:

http://skyandtelescope.com/news/article_1509_1.asp

http://www.cnn.com/2005/TECH/space/05/06/mars.lander.ap/index.html

Dan

Partial Eclipse on Friday!

2005-04-04T08:26:00.000-05:00

This Friday, April 8th, North America is in for a celestial treat that can actually be enjoyed during the day!

The moon will partially eclipse the sun for most of North America between 4pm and 6pm CDT.

NASA Science Article about the April 8th Partial Solar Eclipse

You don't need fancy equipment to safely view a solar eclipse, partial or total. You can easily build a pinhole camera that can project an image of the sun that can be viewed directly.

(image courtesy of ECLIPSE by Bryan Brewer)

If you don't want to go to that much trouble, just stand under a leafy tree!

Trust me!

If you pay careful attention to a tree's shadow during a partial eclipse you'll notice that the normally round "sun specks" in the shadow will have a "bite" missing! The gaps in the leaves of the tree will act a bit like the pin-hole camera above and project an image of the sun on the ground that you can view safely!

This is not something unusual to eclipse time -- the image of the sun is often projected through "pin-holes" all around us, we only especially notice when the round projections have a "bite" missing.

A similar effect occurs if you close the blinds on a window facing a solar eclipse: the holes in the blinds will project the eclipse!

Here's a Sky and Telescope article about the upcoming eclipse: http://skyandtelescope.com/observing/objects/eclipses/article_1445_1.asp.

Enjoy!

Dan

Sky Cartoons!

2005-03-17T22:04:00.000-06:00

Ok, so not everything has to be so serious.

Here are some really nice astronomy-related cartoons that you can enjoy!

The first is Jack Horkheimer's Sky Gazer cartoon archive, which has a new cartoon every month.

The second is the SkyWise archive, brought to you by Jay Ryan. His cartoons were featured in Sky and Telescope magazine from June, 1997 to December, 2001.

Just for grins, here's the Sky Gazer for February, 2005:

Good Night!

How Huygens Almost Wasn't

2005-03-17T06:30:00.000-06:00

Does everyone remember the Huygens space probe which successfully landed on Saturn's moon Titan on January 14, 2005?

(If not, read this: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=530)

The Huygens probe successfully returned multiple images of the surface of this mysterious methane-covered moon which has been compared to a primordial earth.

What is not commonly known is how the Huygens probe came dangerously close to being a complete scientific failure!

Two critical mission errors related to Huygens almost prevented any data being recovered from the landing mission. It was only due to some engineering ingenuity, perseverance, and some luck that we have any data at all from the atmosphere and surface of Titan!

1. The first problem involved the radio communications link between the Huygens spaceprobe and the Cassini orbiter.

When the orbiter-lander mission was launched in October, 1997, extensive electrical and radio tests had been performed to ensure communication integrity between the spacecraft, both connected and separated.

However, this was a very basic test. A more complete full-scale communications test that simulated the actual flight conditions and telemetric data to be handled by the spacecraft had NOT been performed. This more elaborate kind of test was rejected for budgetary reasons, since it would have required disassembly and recertification of the components for spaceflight.

The lack of this comprehensive test bothered one of ESA's ground operations managers to the point that he asked one of ESA's global ground antenna engineers to send a special signal from earth to Cassini, one that simulating the type of signal Huygens would send if it were landing on Titan. What they found was astounding: The data was corrupted depending on the amount of Doppler shift (an effect where the frequency of a wave is changed due to the relative velocities of the wave's source to its recipient).

The effect of Doppler shift was critical: the planned flight plan meant that the Cassini orbiter would be traveling at 5.5 km/s relative to the probe at the time when data would be transmitted. The radio hardware used by the spacecraft had been designed to compensate for the Doppler effect, BUT ONLY for the carrier signal and not for the digital to analog encoding scheme used for the data carried on this signal.

Thanks to this finding BEFORE landing on Titan, the flight plan was changed so that the Doppler effect would be minimized. This changed the Titan landing time frame from November, 2004 to January, 2005.

Read a more comprehensive article related to this discovery that appeared in IEEE Spectrum: http://www.spectrum.ieee.org/WEBONLY/publicfeature/oct04/1004titan.html

See the NASA/ESA press release after discovering the problem in 2001: http://www.jpl.nasa.gov/releases/2001/cassini_010629.html

On to the second major mission error...

2. Half of the data sent from Huygens to Cassini during the landing never made it.

Cassini has two data channels meant to receive data from Huygens, but before the critical moment of the landing transmission one of them was simply not turned on, the command not being sent from earth!

http://spaceflightnow.com/cassini/050115science.html

Fortunately, several of the largest radio telescopes on earth were pointed at Huygens at the moment of the transmission as part of a wind speed experiment. Cassini, combined with these earth-bound radio telescopes, was meant to measure different wind velocities of Titan's atmosphere by measuring the Doppler shift of the carrier signal (Cassini of course would have had to account also for its own high velocity).

After discovering that half of the Cassini data was missing, engineers decided it might be possible to reconstruct at least part of the missing Cassini data using the radio signals gathered directly from earth. The radio telescopes' data was not only able to provide the needed information about Titan's atmospheric wind velocity and direction, but also gave the first indication of the health of the Huygens spacecraft during landing. In addition, scientists were able to gather information as to the precise location of the lander on Titan using the earth data.

http://www.nrao.edu/pr/2005/titanwinds/

So what do we learn from these flaws in the Cassini-Huygens mission?

That to err is human, but with some ingenuity we can persevere.

Good Night!

Get Ready for World Jump Day!

2005-03-07T23:17:00.000-06:00

Want to drive the earth out of its orbit?? Well here's your chance!

There's a web-driven initiative to try to deviate the earth from its orbit depending on how many people participate: http://www.worldjumpday.org/

Basically, these folks want to use the internet to help coordinate how many people jump simultaneously to provide enough force to push the earth out of its orbit on July 20, 2006

The entire theory of pushing the earth out of its orbit via simultaneous jumping, in my opinion, is UTTERLY LUDICROUS!

Why, you ask?

Oh, I can't even begin to name the reasons. Oh, yes I can!

First of all, I guess it depends on how you define "out of its orbit". Technically, the so-called "butterfly flapping its wings" does cause an infinitely small force on the earth, just like my typing right now pushes on the keyboard which pushes on the desk which pushes on the floor ad infinitum.

So the amount you push the earth out of its orbit has to be measurable.

Basically, if you do the math you'll find out that all people on earth jumping at the same time would have about 2% of the effect of pushing on the earth as a modern H-bomb.

That's assuming everyone jumps exactly the same height and the same way and exactly at the same time. And on the same side of the earth, mind you, otherwise you get people in Australia canceling out people in Canada!

Since we know that many H-bombs have been tested on earth, in modern times, and that the earth hasn't yet shifted from its orbit, the idea of a bunch of people managing it on one specific day is simply impossible.

It also depends on what you mean by "its orbit"! The earth does not exactly trace its exact path every year due to a significant amount of gravitation pull by its nearest neighbors, namely Jupiter, Mars, Venus, and the Moon.

Don't credit me here: the physics here I got here come from this website with the best explanation: Ask Mad Physics article on World Jump Day. Or read the discussion going on on kottke.org.

It just goes to show once again how people can take advantage of how the general public forgets to apply everyday physics.

Two examples that illustrates this forgetfulness:

How deep does water have to be for your car to float?? About 24 inches, or 2 feet. See here and here.

Don't even get me started when it comes to a car trying to beat a train at a railroad crossing! When a 15000 ton train is bearing down on you and your 1-ton vehicle, you will soon realize how abundantly important physics becomes!

Good Night!

Slacker Astronomy

2005-03-03T06:07:00.000-06:00

Want to get an astronomy podcast?

Check out Slacker Astronomy.

It's a series of astronomy-related pod-casts (MP3s you can download to your Ipod or other MP3 player) that 3 astronomer-writers have recently started putting on their website, http://www.slackerastronomy.org.

It has been featured on MSN http://www.msnbc.msn.com/id/3217961/.

The site says that they plan to offer insights from "Phantom Astronomers", certified astronomers who can offer their opinions anonymously. I wonder if they'll mask their voices.

Pretty neat!

Dan

New Year is Coming !! Get Ready for 4702!

2005-02-08T08:00:00.000-06:00

Has it been that long??

February 9th, 2005, is the first day of the year 4702 by the Chinese calendar. This year is known as the Year of the Rooster.

The Chinese calendar is based on a lunar calendar in which the first day of the new year falls on the first day after the 2nd new moon after the winter solstice. Since today is the date of the 2nd new moon after the winter solstice, then tomorrow is the first day of the new Chinese year!

Although the date of the Chinese New Year appears to be variable relative to the modern Gregorian calendar, the Chinese calendar is considered to be one of the most accurate astronomical calendars in the world.

According to Chinapage.com:

In 104 B.C. the length of a year was determined to an accuracy of 365.2502 days. By 480 A.D., Ju Chongzhi refined it to 365.2428 days, or 52 seconds more than the modern value of 365.2422 days. To put it another way, in 2,000 years the total discrepancy is less than one day!

As everyone knows, the modern international Calendar (based on the Gregorian calendar) uses a system of leap years and leap days to account for the fact there is a fractional day (0.2422) in addition to the standard 365 days per year. (More about the Gregorian Calendar here).

The Chinese Calendar, on the other hand, uses a different system to account for this discrepancy. Since a lunar cycle is 29.53 days (from new moon to new moon) then are 12.3685 lunar months in a solar year (365.2422 days). So most years will have 12 lunar months. The fraction of a lunar month is taken into account by every few years containing an additional leap month. Seven years out a 19 year cycle have a leap month, the exact years determined by a complex set of rules.

Read a much more detailed explanation at Wikipedia.com.

Good Night!

Dan

p.s. Check out Wikepedia.com! It's a FREE online encyclopedia that anyone can edit! The global online community ensures that the content stays accurate!

SMART-1 images the moon

2005-02-01T02:27:00.000-06:00

The SMART-1 spacecraft has successfully gathered images of the Moon at altitudes of between 1000 and 5000 km above the surface.

Moon image using AMIE's clear filter View of lunar crater, or is it a dome?

ESA Article: SMART-1's first images from the Moon

SMART-1 is the first mission to the Moon by the European Space Agency (ESA). The little probe will gather high and medium resolution images of the surface of the Moon from various angles using various light filters that will serve to answer the question "Where did the Moon come from?".

Despite voluminous data gathered as a result of US and Soviet space programs during the '60s, '70s, and '90s, much mystery remains as to the origins of our Earth's largest natural satellite.

SMART-1 is the latest in a series of scientific successes by the European Space Agency (ESA) including the notable landing of the Huygens probe on the Saturnian moon Titan on January 14th.

Despite the objective of gathering scientifically important lunar images, a secondary goal is to test key technologies such as solar-electric propulsion which basically involves using electricity generated by the solar panels to produce a beam of charges particles that are expelled from an engine, producing thrust. This engine is known as an ion engine, which is more fuel efficient than previous designs. More about ion engines here: Ion drives: Science fiction or science fact?.

Read more about SMART-1 and other ESA projects at the ESA website.

Good Night!

When is North not North?

2005-01-18T22:30:00.000-06:00

Depends on WHICH North you mean and WHEN you mean it.

If you look closely at some maps, you'll notice that there are THREE linear directions referred to as North:

(image courtesy map-reading.com)

Grid North: The north that is established by using the vertical grid lines on a map. Grid north may be symbolized by the letters GN.
True North: A line from any point on the earth's surface to the geographic North Pole, that point on earth containing the earth's spin axis (in conjuction with the South Pole). Lines of longitude are True North lines. True North is usually represented by a star, since in reality the North Star, Polaris, is very close to True North. Can also be indicated by the letters TN.
Magnetic North: The direction to the North Magnetic Pole, as indicated by the north-seeking needle of a magnetic instrument. Usually indicated by the letter N or MN.

Why are they different?

Grid North
Grid North lines are the vertical lines represented on some maps. These GN lines do not necessarily match the True North lines of longitude because a map is a flat (2-D) representation (or projection) of a curved (3-D) surface. Conversely, lines of longitude will not appear perfectly straight on a 2-D map projection.

(image courtesy John Sharry, petroleum geologist)

The map above shows a sample projection (conic) of North America. Notice that the True North lines (lines of longitude) all converge to a single point, the North Pole, but Grid North direction (parallel with the side of the map) doesn't really converge to a single point. Some map projections are better than others, depending on what region of the earth is to be projected. Read more about map projections here: University of Colorado Dept. of Geology.

True North
Ok, so TN should be reasonably accurate, right? As long TN stays on earth, that is.

True North refers to a line drawn from any point on earth to the North Pole. The North Pole, also called Geodetic North, is one of the two points on earth that contain the earth's spin axis (in conjuction with the South Pole, or Geodetic South).

Early navigation used the celestial cousin of the North Pole, called Astronomical North or Celestial North. Celestial North is that point in the night sky around which all the stars appear to rotate (if you live in the northern hemisphere). So, if you were to stand on the North Pole, Celestial North would be directly above you.

It should be made clear that although True North doesn't move over time, Celestial North does. Why? Because the earth's axis wobbles as it spins in space! This "wobble" is called precession and has a period of about 23000 years.

(images courtesy The Electronic Universe)

Earth's precession is caused by the gravitational pull on the earth mostly by the moon, but also by the sun. Celestial North, also called the North Celestial Pole, is roughly 45 minutes of arc (0.66 degrees) away from Polaris, the North Star, which marks the end of the constellation of the Little Dipper. But Polaris wasn't always the North Star. In 3400 B.C., when the Egyptians were building the Great Pyramid of Giza, the closest bright star to Celestial North was the star Thuban in the constellation Draco. As you can see, time plays an important part in calculating star positions.

Magnetic North
Earth has a magnetic field whose magnetic lines of flux begin at a "north pole" and end at a "south pole", just like a magnet. See the lines of magnetic flux in the image below.

(image courtesy NASA)

The needle in a compass aligns itself with these "lines of flux" and, in effect, indicates the north and south directions. Surprisingly, the earth's magnetic "north pole" is not aligned with the True North Pole! This means that the north pointed to by your compass is not True North! This is because the magnetic field depends on the magnetic polarization of the molten rock in the earth's core, which has unevenly distributed magnetism.

However, for practical purposes this difference between MN and TN (called the "declination") can be assumed to be constant for the small regions on earth covered by most maps. For example, in Texas the Declination is about +6 degrees. This means that if your compass tells you you're traveling at a bearing of 10 degrees, you're really going 16 degrees. But this declination doesn't stay put over time. The molten iron in the core moves as the earth's geologic nature is ever changing. This means that, even more surprisingly, the earth's Magnetic North changes over time!

(images courtesy Geologic Survey of Canada)
The left image above plots the position of Magnetic North from its discovery in 1831 in northern Canada until 2001, according to the Geologic Survey of Canada. In those years the MN has moved over 1100 km (660 mi). That's an average 3 miles per year! Most of that movement has occured in the last 35 years when the movement has increased to about 24 miles per year. The image at right above shows that the predicted position of the MN in the year 2050 to be near Siberia, Russia. Read a CNN article talking about the movement of the MN from Canada into Russia.

Not only does the Magnetic North Pole move from year to year, but every few millenia the polarity of Earth's magnetic field REVERSES ITSELF!!!

(image courtesy USGS Earthquake Hazards Program)

This image illustrates the polarity of the rock on the ocean floor as it emerges from an intercontinental rift. Scientists have found that the ocean floor has strips of rock of opposite magnetic polarity that appear to be about 500,000-700,000 years apart. During a reversal period the earth's magnetic field is weak causing compasses to likely be very inaccurate. This weak magnetic field would also allow much more solar radiation to enter earth's atmosphere, likely causing Solar Aurorae to move beyond polar regions.

Read more about magnetic reversals at these sites:

A Last Word About "Orientation"

North was not always the direction considered to be UP on maps. Prior to the popular use of the magnetic compass and stars for navigation, east was considered up on most European maps. There are many explanations for this eastward facing map, including pointing the map to the rising sun, towards the Orient or towards Jerusalem, considered the Holy Land by Medieval Europe. The word Orient is in fact derived from the Latin adjective 'oriens' derived from the verb 'oriri' meaning 'to rise or come forth' which in the English language came to refer to the location of the rising sun at the equinoxes, i.e. East (reference from Wordwizard.com here). The word orientation in English then came to be known as obtaining ones' direction or bearing based on this East-centric map.

North is not South
Now you're probably all wondering about South? So I don't have to write all of this again, just flip everything upside-down (or back to right-side-up for those of you "down under").

(image courtesy the Upside Down Map Page)

Good Night!

Huygen's Entry on Friday!

2005-01-10T08:30:00.000-06:00

Mark your calendars! We're sending an away team to an alien planet!

The Huygens probe, part of the Cassini mission to Saturn, was released from its "mother ship" Christmas Eve (Dec. 24th) and will enter the atmosphere of Titan at 4:15am CST on Friday, January 14th.

Titan is the only moon in the solar system to have an atmosphere and is supposed to be similar to a primordial earth. Information from Titan is vital to understanding the formation of life on earth! Scientists are unsure if the Huygens probe will land on a hard surface or on one of its methane lakes. It is better if the probe lands on liquid since it will be more likely to survive a splashdown and be able to return some images.

Splashdown/touchdown is expected on Jan. 14th at 6:30am CST. It will then take about 2 grueling hours for the data to return from Titan given the limited speed of light. Cassini will be acting as a relay station for the probe since Huygens does not have the power to transmit the signal to earth.

Incidentally, the Huygens probe is named for Chistiaan Huygens, a 17th century Dutch physicist and astronomer who first described the nature of Saturn's rings and discovered Titan. He also developed the use of the pendulum in clocks.

To follow all of the latest news from Saturn and Titan, visit: http://saturn.jpl.nasa.gov/. There will likely be a streaming video from JPL and a live broadcast on CNN on Friday morning.

To learn more about the mysterious world of Titan, visit: http://www.nineplanets.org/titan.html

Good Night!

p.s. Don't worry, if you're a member of my email list, you'll receive an email reminder the day before. Not subscribed? Just send an email with any subject and body to: skywonders-subscribe@skywonders.com. In order to filter out SPAM, you'll get an email response confirming your email address before the subscription becomes official. Just follow the instructions.

Don't Panic: Winter Solstice is here!

2004-12-21T22:02:00.000-06:00

The winter solstice for those in the Northern Hemisphere has finally arrived! It occurred today at 12:42 UT (that's Universal Time, equivalent to Greenwich Meridian Time, or GMT), or 7:42am EST (6:42am CST).

So what is the solstice, why does it mark the start of winter (in the north), and why do we have all of these big celebrations at this time of year?

The seasons of the year are caused by the tilt of the earth (23.45 degrees) relative to the plane of earth's orbit, the ecliptic.

(image courtesy MSNBC)
This tilt causes the daily arc that the sun traces in the sky to change from day to day throughout the year. In the Northern hemisphere the sun's daily arc is highest at the summer solstice (June 21-22) and lowest at the winter solstice (Dec. 21-22). (If you want to know why the hours of day and night aren't exactly equal at the equinoxes, see my previous article: Vernal and Autumnal Equinoxes.)

(image courtesy Sandburg Center for Sky Awareness)
The term "solstice" comes from the Latin sol stetit, meaning "sun standing still". To the ancients, the day-to-day drift of the sun's arc would appear to stop drifting at the times of the solstice.

Many ancient cultures placed a lot of importance on the winter solstice (again in the northern hemisphere). Many held worship ceremonies to sun gods to encourage the sun to stop its southward travel and march back north again. These peoples would celebrate and rejoice the time of the winter solstice because it marked new life with the increasing daylight. Many Christmas and Hanukkah traditions are based on ancient winter solstice traditions, including the burning of the Yule log (this information from an article at the Boulder Public Library).

One curiosity with which I have always struggled is that the Winter Solstice is considered to mark the beginning of winter. I have always felt that the Winter Solstice should mark the middle of winter instead of its beginning. This would put the beginning of winter roughly in the first week of November, rather than the 3rd week of December.

Interestingly enough, ancient cultures believed the solstice to mark the middle of winter. Ancient Chinese calendars, for example, mark the "Start of Winter/Summer/Spring/Fall" to be offset by several weeks from "Autumnal/Vernal Equinoxes" and "Winter/Summer Solstices".

Although you may have heard that the Winter Solstice is the "official" start of winter, there is no official body that makes this designation. In Alaska, the beginning of winter is considered to be on the first full day where the air temperature does not rise above 0 degrees Celsius (freezing point of water). In Albany, New York, the start of winter is considered to be after the first snowfall. Meteorologists like to define the three coldest months, December, January and February as the the three months of winter for data collection and research purposes.

Part of the problem is that the season of Winter is defined differently by different cultures. So relating the start of winter to an exact astronomical event like the solstice is what is currently accepted by modern news media, although this practice truly is without meteorological, agricultural or historical merit.

So have a Happy Winter Solstice Celebration, whatever your culture!

Good Night!

Meteors, Lightning and Bugs, Oh My!

2004-12-10T20:56:00.000-06:00

An interesting photo has appeared on the NASA Dec. 7, 2004 Astronomy Picture of the Day (APOD).

It shows what appears to be a meteor crashing into the water near a dock in Darwin, Australia:

The photographer claims that the photograph is real: part of a series of photos taken automatically every 15 seconds as part of an atmospheric cloud study. Scientists who have inspected the digital photograph do not think it is a meteor or lightning and the light pole near the flash in the image does not appear to show any damage. No one in the vicinity at the time of the photo have reported any strange events. So, assuming it's not a hoax, what created this image?

The interesting part to me is that an INTENSE online discussion has been going on for the past three days to attempt to explain the above photograph. See the discussion online here. Needless to say I have participated a little in helping to solve this mystery.

So far the theory best supported by the evidence created from intense image analysis by a surprising number of online detectives is that a bug crossed in front of the camera during the exposure. The shutter was open for 1/20th of a second during which time a fly/bug crossed in front of the camera. The bug's body (but not its translucent wings) blocked some of the light from the sky from reaching the camera. Near the end/beginning of the exposure, a flash was fired (as evidenced from digital data stored in image) which illuminated the bug and it wings creating the apparent flash in the image. Bugs have been known to create strange images in photographs as evidenced from the Roswell Rods.

Hopefully sometime soon APOD will update their page to agree with this conclusion. But don't let me sway you with my opinion! Read the online discussion yourself above and better yet, participate in the mystery! Until, look at this image generated by someone online showing the difference between the strange image and others taken in the photographic sequence:

Good Night!

Get Ready for Geminids on Dec 13th!

2004-12-08T22:54:00.000-06:00

The annual Geminid meteor shower is coming on the evening of Monday, December 13th! It's expected to be good!

Get ready like I am by reading the 2004 Geminids Article on the NASA Science Site.

You too can sign up and receive daily Science News from NASA. Click on the image below for the sign-up page.

Good Night!

Explore the Solar System here on Earth!

2004-12-04T23:47:00.000-06:00

See how well you do at the following simple trivia questions:

How big is the Moon?
How big is the Earth?
How big is Jupiter?
How big is the Sun?
How big is Pluto?
How far is the Moon from the Earth?
How far the Earth is from the Sun?
How far is Jupiter from the Sun?
How far is Pluto from the Sun?

Give up? Here are the answers:

The Moon is 2160 miles in diameter
The Earth is 7926 miles in diameter
Jupiter is 88,800 miles in diameter (at equator)
The Sun is 893,000 miles in diameter
Pluto is 1412 miles in diameter
The Moon is 238,900 miles on average from Earth
The Earth is 93,000,000 miles on average from the Sun
Jupiter is 483,600,000 miles on average from the Sun
Pluto is 3,675,000,000 miles on average from the Sun

Ok, so why are these solar system dimensions so hard to remember? (except for maybe the 93 million miles -- people seem to remember that one for some reason.) Because they're very BIG numbers that go beyond our everyday understanding. Most of us need to see things in comparison to other things to get some sense of how big or far away they are.

It seems that what we need is a model of the solar system just like we use a globe to see what the continents look like on Earth.

The only problem is that the smallest object in the model, Pluto, has to be 2.6 million times smaller than the largest distance in the model, the Sun-Pluto distance. The immense distances between planets in our solar system as compared to their sizes is why making an accurately "to scale" solar system model to be very difficult.

The best we can do is to make our model big, very, very big.

Currently there are at least 14 true to scale solar system models that I could find on the web. The solar system model in Peoria, Illinois, USA claims to be the world's largest at about 40 miles between the Sun and Pluto. Funny enough, the solar system model in Aroostook County, Maine also claims to be the world's largest, also at about 40 miles between the Sun and Pluto.

See a list of more solar system models at the site of the Alachua Astronomy Club, which is currently rebuilding their own Solar System model, which apparently has gone missing: Florida Solar System Walk.

You can make your own solar system model by visiting the Solar System Model Calculator. You simply enter the diameter of your Sun model (in inches or mm) and the calculator will give you the resulting sizes and distances to scale of the rest of your model.

Here is a great article on building a thousand yard solar system, if the earth were the size of a peppercorn: The Thousand Yard Model, or The Earth as a Peppercorn.

See more references here: Solar System Model metapage

Good Night!

See the Sky Live from your PC!

2004-11-30T18:38:00.000-06:00

Every want to view the stars from a really dark sky location but don't have the time to go there?

Or what about going south of the equator and viewing objects not visible in the northern hemisphere?

Check out Night Sky Live Project website. This project involves a network of cameras with fisheye lenses taking live pictures of the skies all over the world!

Each camera is setup to take a 180 second exposure every 4 minutes, and you'd be surprised what it can pick up!

The image above shows an image taken in Mauna Kea, Hawaii. The bright band in the middle is our Milky Way galaxy! Some major stars and planets have been marked on this image for reference.

There's even a discussion board where you can review images you have seen with others. You can even review an archive of previous images. With tons of people on the internet reviewing images, who knows what unusual objects may be found?

So cloudy days are no longer an excuse for gazing up at the wonders in the sky above!

Good night!

Know Your Constellations!

2004-11-26T09:01:00.000-06:00

Do you know your constellations?

If it's one thing I've repeatedly discovered on a clear night out with others is that most people don't know their constellations. Which is a shame since knowing your constellations is such a basic and easy skill that connects you with people all over the earth just as much as knowing how to find the moon.

I love knowing the constellations. It makes the sky a familiar place.

One of the easiest ways to first learn your constellations is to get a planisphere. A planisphere is basically a flat map of the sky drawn on a flat piece of paper, plastic or cardboard. It includes a rotatable mask that only exposes the part of the sky visible at your location, time and date. Each planisphere can only be used for certain latitudes on earth.

The image below shows an example planisphere. You simply line up the date with the time and it shows you the sky at your location (image credit: Sky and Telescope):

Notice from the image that the sky will look the same on December 17th at 10pm as it does on January 16th at 8pm! That's because for every day that passes, the stars rise about 4 minutes earlier. This adds up to about 2 hours over the course of a month. This apparent shift of the stars day to day is simply the result of the earth traveling around the sun.

Click on the image above to read an excellent article on Sky and Telescope's site for more on how to use a planisphere.

You can purchase planispheres online at several sites:

David H. Levy's Guide to the Stars Planisphere - $19.95
Night Sky Miniplanisphere - $5.95 - good for a small one
Precision Planet and Star Locator - $20.95 - the "mercedes" of planispheres
Orion Star Target Planisphere - $9.95

As you can see, planispheres come in different sizes, styles and prices (make sure it is correct for your latitude).

If you don't want to spend money on becoming familiar with the stars, you can download a planisphere template from discovery.com: Planisphere template. You just print out the pages, cut and put them together! Make it a project with any young ones in the house!

Learning the sky can ALSO be done by going to skymaps.com. Here you can get FREE PDF printouts of what the sky should look like every month, and for BOTH hemispheres!

So how did I learn the sky? I learned some from websites like these, but mostly from having 2 star map posters, one at home and one at the office. I also learned from Jay Pasachoff's book: A Field Guide to the Stars and Planets which includes 52 atlas charts of the sky.

So get out there and learn the constellations today!

Vernal and Autumnal Equinoxes

2004-11-21T19:07:00.000-06:00

Ok, so here's my first attempt at answering a "viewer question".

Ken writes to ask:

"Why don't Vernal and Autumnal Equinoxes have exactly equal night and day? Usually the Equinoxes fall around 22nd of March/Sept. Ideally, there should be 12 hrs separating sunrise and sunset. It's close, but not exact. Usually, the 12hr sunrise/sunset days fall a few days before or after the equinoxes. Why is this?"

First of all, you usually hear of two definitions of the equinox:

The "terrestrial" definition is when the sun rises exactly due east and sets exactly due west. It is believed that at this moment we get exactly 12 hours of daylight and darkness. In fact, the word equinox comes from the Latin "equi nox" meaning "equal night".

The "astronomical" or "celestial" definition refers to the moment when the center of the sun crosses the celestial equator in the sky. The celestial equator is the imaginary circle in the sky that lies above the imaginary equator on earth. It is this definition that is more commonly used today.

Both of these definitions are equivalent. Both result in the same moment in time being defined as the equinox.

It is when you bring "daylight" into the picture that it gets all messed up!

We know that due to the tilt of the earth's axis relative to its orbit, the sun spends most its time either north of south of the equator and for this reason the days are usually longer or shorter than 12 hours most of the time. We expect that when the sun is directly over the equator that we should get a perfect 12 hour day.

Shouldn't we?

Not if we take daylight into account, because of 3 reasons:

The sun is not a finite point source of light.
The earth has an atmosphere.
At the moment of the equinox, the earth is not rotating.

Huh?

As humans we generally measure the "day" as the time between sunrise and sunset. Sunrise is defined as when the TOP EDGE of the sun breaks the horizon and sunset is defined as when the TOP EDGE disappears below the horizon. Equinox is measured based on the CENTER of the sun's disk, not at the edge. This difference means that at the equinox moment, the day is actually slightly LONGER than 12 hours.

Not only that, but the earth's atmosphere refracts (bends) sunlight coming over the horizon so that the sun appears to have risen even before it really has. This adds 7-8 more minutes to the length of the day at the equinoxes.

Both of these effects combine so that the true 12-hour day for high northern latitudes can occur several days before the Vernal Equinox and several days after the Autumnal equinox. The effect is lessened for latitudes closer to the equator. And the opposite holds true for those latitudes in the southern hemisphere.

In addition, since the earth is not rotating at the actual moment of the astronomical equinox (can't rotate if there is no time change) then only certain points on earth even see a sunset or sunrise at the ACTUAL moment of the equinox. And then the other end of the day for those locations would be before or after the equinox anyway. So no one location on earth can possibly see a sunrise and sunset at the equinox moment.

Still, this third "effect" does not contribute to the lengthening the day as much as the other two.

Hope this answers it!

The U.S. Naval Observatory provides tables for earth's perihelion, aphelion, equinoxes and solstices until 2020. Notice that these equinoxes change from year to year due to the earth's precession (the "wobble" as it spins on its axis). Notice that in a leap year the day changes by 1 for the obvious reasons.

WORD OF WARNING: Never confuse equinox with the 12-hour day. The former happens at the same time for everyone on earth. The latter is dependent on your location.

Now I won't pretend that I knew all that off the bat! But having some ideas and after a thorough internet search revealed the true answer.

Another USNO reference: http://aa.usno.navy.mil/faq/docs/equinoxes.html

Good Night!

Ask Astro Questions!

2004-11-20T22:25:00.000-06:00

Have an astronomy question you'd like me to research the answer to?

I love astronomy like you wouldn't believe, and have the crazy desire and curiosity to understand things I've been asked. I also have a veritable library of space and astronomy books just sitting behind me waiting to reveal their treasures.

So take advantage! Ask to your hearts content! I'll be sure to post an article sometime in the future to your questions.

Make your questions a comment to THIS article so I can consider them as future articles.

Good Night!

Sky Watching Weather

2004-11-17T21:08:00.000-06:00

If you need weather info that is more geared toward the amateur astronomer, check out the Clear Sky Clock Home Page.

This unique website extracts data from the Canadian Meteorological Centre. The CMC runs 3 computer weather simulations every 12 hours and generate images of future weather conditions across North America for cloud cover, transparency and seeing conditions. The Clear Sky Clock website extracts data from the CMC to generate a "Clear Sky Clock" for any particular location.

This is the Clear Sky Clock for Austin, Texas:

The above image is a running clock! If you hit refresh it will periodically update.

They even provide a small thumbnail image that is easier to fit on your website, it's just a little harder to read:

See the map below showing the latest CMC data with superimposed Clear Sky Clock locations.

If there isn't a location near you, you can even request that Clear Sky Clock be added.

For me it looks like there are a couple of holes in the sky above Texas finally after a week of flooding rain!

It's too bad you can't get a clock like this on your wrist!

Good Night!

Sky Calendars

2004-11-15T21:42:00.000-06:00

Want to know what's going on up there? (in the sky I mean)

Maybe you just want to know what interesting astronomical events are happening these days.

Here are few useful sites I've found and used:

Sky and Telescope's Week at a Glance Provides daily events for a single week.
StarDate Weekly Stargazing Tips Another weekly event update.
Sky Calendar at Abrams Planetarium at Michigan State University. Provides a good printable PDF calendar.
Que Tal? Earth/Space science newsletter.
JPL Space Calendar Gives listings of asteroid and comet close approaches, spacecraft launch dates, famous anniversaries and birthdays, lunar and planetary events, as well as the dates for related conferences (in case you planned on going). For example, today the spacecraft SPACE-1 entered lunar orbit!
Stig's Sky Calendar Supposed to be very good-- I've seen many sites refer to this one --assuming the Java on the embedded applet works. I've not yet seen it work. Check back.
Astroevents -- Good calendar showing lunar and planetery events. Updated monthly.

I hope to eventually add my own sky calendar to this site. Until then, keep checking back at these links!

Good Night!

More Aurorae!

2004-11-14T21:48:00.000-06:00

Check out more of the pictures of this week's aurora borealis that dipped down into the middle US: http://www.spaceweather.com/aurora/gallery_01nov04.htm
Be sure to check out all the pictures!

See some of my favorites:

Hope you had a good weekend!

Good night!

URL Change: Skywonders.com

2004-11-14T13:04:00.000-06:00

Having trouble remembering the URL for this site? I've set up a URL redirect so that you can just go to http://www.skywonders.com and it will take you here.

So bookmark the new link and enjoy!

What To Do On Cloudy Days

2004-11-13T20:03:00.000-06:00

Today is a heavily overcast day in Austin. There couldn't possibly be anything related to astronomy to talk about. Or could there?

I was just remembering today the legend of how the Vikings would find their way around on the high seas using what has later been called a "sun stone" for navigation. The idea was that they had a rock that would change color depending on the angle of light from the sun hitting the rock, even on a cloudy day! They used this special stone to find the sun, and thus find to roughly find north and south! Historians believe that the stone they might have used is a calcite material called Icelandic Spar which reflects and filters polarized light.

Polarized light is light that behaves differently in different directions. The light from the sun becomes partially polarized when it hits the atmosphere and gets scattered. Since most of the sun light still comes from the direction of the sun and only some of it comes from every other direction (making the blue sky) we say that the light is polarized to the direction of the sun.

"Polarized" sunglasses use special lenses that filter only horizontally polarized light. They are made to filter light that gets polarized when it reflects off of horizontal surfaces like the surface of water. This helps not only fishermen and sailors, but also drivers who see a lot of this kind of light reflected off of cars in traffic.

If you have these kind of glasses you could probably use your own "sun stone" to find the sun on a cloudy day! Put the glasses on then look at the clouds. Tilt your head left and right until you notice that the light appears darkest. The spot above your head is roughly in the angle of the sun. Try turning around too to see if that changes the brightness of the light you see.

Historians and scientists are still unsure if the Vikings could really navigate on the open ocean on a heavily overcast day because the light would be so scattered as to make it difficult to measure the direction of the sunlight. It is more likely they could only use the sun stone on partially cloudy days, or only when there was a small opening of clear sky.

Experiment on your own to see if you can find the sun on a cloudy day!

To learn all about polarization and how maybe the Vikings used a sun stone to navigate on the ocean on cloudy days, visit:

Polarization website Vikings page
Polarization website explaining how polarized sunglasses work
Excerpt from 1997 Sky and Telescope sun stone article
Navigating Viking Ships

Good night!

Easy Sky Map!

2004-11-12T21:48:00.000-06:00

Looking at the sky and don't know what you're seeing? Don't have a star program on your computer? Don't know your latitude and longitude?

Well I've found a link just for you!

It's the interactive sky chart on Sky and Telescope's website.

Just click on the link below then on "View Sky Chart". Change your location by choosing your zip code, country and time zone and then your chart will be ready for your spot on the earth!

Sky and Telescope Interactive Sky Chart
The chart has a neat combined view which shows you both the entire sky and a zoomed in view of part of the sky that you choose. You can even print out either view!

Enjoy!

Dan

3-D Universe

2004-11-11T20:32:00.000-06:00

This amazing website that allows you to view the universe in 3-D!

Using either stereo red/blue images or stereo pairs that require cross- or wide-eyed viewing, this stereo chart generator can show you the relative distances to stars in any patch of sky. (One word of warning: use the advanced charts, the basic charts do not appear to be compatible with all browsers).

There are also animations showing either how it would look traveling through a familiar constellation or watching how constellations change with the progress of time.

The animation below shows what Orion would look like if Earth's orbit were 50000 times bigger, exaggerating the parallax (the amount of apparent shift of nearby objects relative to farther ones). The stars that appear to shift the most are those that are closest.

But the best way really is to look at the stereo pair images, if you can successfully accomplish crossing your eyes. Here's one of the Ursa Major (Big Dipper):

Needless to say there's a lot to find on this site. Give it a look!

Good Night!

Eagle-Eye Astronomy

2004-11-10T21:51:00.000-06:00

If you've ever wanted to claim to see the farthest thing than anyone else, now is your chance!

At 25 million light years, the Andromeda Galaxy takes the prize for the farthest object in the night sky visible to the naked eye.

Even in the darkest sky with the best of eyes, you can only see roughly 2000 stars, all of which are part of our own galaxy, the Milky Way. The few nebulae visible to the naked eye (The Orion Nebula, Lagoon Nebula, Trifid Nebula) all reside within our own galaxy.

So we have to look beyond our galaxy to see extraordinarily distant objects.

Despite popular belief, the Andromeda Galaxy IS NOT the closest galaxy to our own. Until recently, astronomers thought that the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) galaxies were the closest. Since these are only visible in the southern hemisphere, most North Americans have never heard of them.

The Sagittarius Dwarf Galaxy, however, was only recently discovered in 1994. It is very large fuzzy patch of sky above Sagittarius in the direction of the center of our galaxy. Scientists simply didn't notice it before because it is so large and dim, and being in the direction of the Milky Way's center, has a large number of Milky Way stars in front of it. It is believed that this dwarf galaxy is slowly being ripped apart by the extreme gravitational forces of our galaxy.

This map of the constellation Sagittarius shows the position of the Sagittarius dwarf as a blue cloud. Since the constellation is also known by its asterism as "The Teapot", the dwarf galaxy makes it appear that "The Teapot" is steaming!

I just think that's downright neat and I'm not afraid to say it!

Getting back to the Andromeda Galaxy, M-31 will be almost directly overhead in the night sky (for mid-Northern latitudes) until early January.

To help you find M-31, here is a sky map and a closeup star map.

For more info about M-31, visit the SEDS M-31 page

Good Night!

Do you know your constellations?

2004-11-09T22:10:00.000-06:00

It's always amazing to me how many people don't know their constellations! Such a ubiquitous thing, the night sky, but so many only know maybe the Big Dipper-- and that's only an asterism, not a true constellation!

It's so easy to familiarize yourself with the sky, it's basically connecting the dots-- it's like a familiar roadmap that only changes 4 minutes a day really! (24 hrs/365 days = 4 minutes a day).

I love to watch the night sky, connecting the dots, trying to figure out how the constellations are oriented on a night without looking at a star chart. Like driving without a road map.

The other night I was looking to the east thinking that the bright object I was observing was a planet-- it HAD to be-- it wasn't twinkling. But after thinking about it, I realized that the ecliptic (the what you say?) was further south and east than this "planet"-- it had to be part of the stars around it. Sure enough, I eventually recognized Auriga (who?) through the light pollution-- the "planet" was the star Cappella.

People (and I mean the general non-astronomical public) seem so amazed when you point out a planet or a star to them. It's like being amazed that someone knows that the Starbucks is at the corner of Main and 1st.

But that's just me I guess-- it's not like astronomy HAS to be something left only for physics majors and nerds behind telescopes. Astronomy really and truly affects our daily lives (unlike it's evil twin, Astrology).

Think about your seasons-- astronomy. Your tides-- astronomy. Your moon phase, your sunset, your blue sky, your satellites, your aurorae, your winter, your summer, your weather, your UV radiation, your north and even your south are all affected by astronomy. Shoot-- I forgot our 24.25 hours a day, which is slowly getting longer-- all astronomy.

Ok-- so I've gone off the deep end. Maybe it just amazes me how many folks are completely unaware of their surroundings to even notice that the moon is visible during the day, that the sun is NEVER directly above in North America (we're too far north of the Tropic of Cancer) and that which is the greatest ignorance of them all : THE SEASONS ARE REVERSED WHEN YOU CROSS THE EQUATOR.

I'm from Argentina, and MANY, MANY times I would get amazed faces when I mentioned that my summer vacation in Argentina was spent in cold, winter weather. Are we not aware of this spaceship earth? Do we only know that the earth is round because Columbus discovered it? (He didn't, of course, a spherical earth was well established when he "sailed the ocean blue". He only thought it was 1/3 smaller than it truly was. Thus the erroneous "West Indies".)

I guess the public response is "So what?". So what that we are moving on an earth that is traveling 70,000 miles per hour around the sun. So what the the moon is moving away from us 4 cm every year thanks to increased orbital energy we impart thanks to tidal locking. So what that we have 2 tides per day thanks to the moon-- and so what that the moon itself is responsible for the earth having such a stable 23.5 degree tilt as to keep a cycle of seasons that is suitable for life on this remote 3rd rock from the sun.

So what I say! Maybe we need to ignore all that occurs outside our atmosphere and first fix all of the problems inside of it. Spend no time gazing at the stars, taking pictures of the moon, sending robots to other planets, take no time learning the structure of comets, asteroids, stars, rings, space, solar wind, or black holes. Let's have none of it! It's all hogwash I say!

Remember that the same has been said of philosophy and art, of poetry and theatre, and in general of human learning and exploration. Why do we bother to study history, geology, paleontology, since they don't give us anything of advantage?

Because, if we don't understand ourselves and where we came from, or at least our place in the universe, we can't hope to put our gains and lives in perspective.

Getting off my soapbox, bare minimum I think astronomy could have a direct impact in preventing some future NEA (near earth asteriod) from making all of our problems seem minute.

Just my take.

Anyway, where was I ? Constellations?

So check out this cool website where you can get PDFs to print out of the night sky for every month of the year: http://www.skymaps.com/

Then go outside and take a gander.

It's about time.

Good night,

Dan

Aurora Borealis!

2004-11-08T21:12:00.000-06:00

Wow! Every day a new wonder! Yesterday observers in Utah and Colorado reported seeing Northern Lights!

The cause was an intense electromagnetic eruption from the solar region near sunspot 696, a CME (coronal mass ejection), that hit earth head-on yesterday. A cool graphic on the SOHO website shows the extent of the aurora in the north, covering all of Canada, Greenland, Iceland, Russia, half of the US and half of Europe!

What is a CME? The SOHO website defines it as "A huge magnetic bubble of plasma that erupts from the Sun's corona and travels through space at high speed".

Check out a CME in action! Click on the image below for a cool MPG:

For size comparison, the white circle in the center of the image is an outline of the sun's disk.

Anyone out there?

2004-11-07T22:05:00.000-06:00

I've added some new features to the blog this weekend: a "Current Moon Phase" image that is updated thanks to the U.S. Naval Observatory, and a "Current Earth Map" which shows a flat earth map with night areas shown thanks to Fourmilab Switzerland (a website unrelated to Fermilab in Illinois). The second one took some investigation on how to implement, but it was fun to figure it out.

It just occured to me though that no one has probably started to even look at my new blog yet and so no one will not particularly notice the "improvement" anyhow (the tree falling in the forest syndrome).

Still, I expect that I will have readers soon-- the point for me is to get writing about this topic that I love.

So, for those of you that find this message far, far in the future, a disclaimer:

HELLO, we are friendly people of earth that have only recently discovered how to instantly communicate across our planet. We sometimes get so excited about communicating that we do it even if no one is really listening. Therefore, please consider the half-duplex nature of this communication method into account when interpreting this information. In addition, please take into account any improvements in science, technology or society made by the time you read this that could invalidate all conclusions made herein.

Thank you,

Dan of Earth

Leonids are coming! (we think)

2004-11-06T13:07:00.000-06:00

The earth is again expected to enter the trail of dust left by Comet Temple-Tuttle for this year's Leonid meteor shower!

Unfortunately for North Americans, the latest prediction from the IMCCE in France (endorsed by NASA) is that the peak of the meteor shower, which will be on Nov. 8th around 23:30 GMT (5:30pm CST), will only be visible in eastern Europe and western Asia at a rate of 50 to 100 per hour.

Previous to this latest prediction, online sources including Sky and Telescope were expecting the annual meteor shower to occur closer to November 17th at only a rate of 15 to 20 per hour.

This latest Leonid prediction is based on recalculations by the IMCCE using older dust trails of Comet Temple-Tuttle comet than before, which makes it more likely for a more intense meteor shower.

From my location in Austin, Texas, I'll be watching on both dates just in case. On both Nov. 8th and 17th I'll be getting up at at 3:00am CST to look towards the constellation Leo, which will be towards the east just over the waning crescent moon.

Technically, you don't watch a Leonid meteor shower by looking at Leo. You put Leo behind you and look directly overhead to catch the streaks in the sky coming from Leo. Here's a good S&T article on how to observer a meteor shower.

Have fun!

Orion Mystery

2004-11-05T21:01:00.000-06:00

Saw this book at Barnes & Noble the other night while browsing books with the family. I had heard of the correlation between the Great Pyramid at Giza and the stars before but the specifics presented here are truly amazing!

Basically the layout of the pyramids relative to the Nile is very similar to the layout of prominent stars relative to the Milky Way.

Not only are the 3 stars in Orion's belt correlated to the 3 pyramids on the Giza plateau, but at least 4 other pyramids have been associated with 2 corner stars in Orion and the 2 stars that tip the horns of Taurus!

I liked that the book is presented as one researcher's quest to understand the purpose of the Great Pyramid. Notebly it does not attempt to assign any great mystical powers to the pyramid (pyramidology) but the more legitimate science of understanding ancient Egyptian society and why they needed to build these fantastically enormouse structures (egyptology).

For more discussion on this book on sci.astro.amateur, go to this link.

Links Ho!

2004-11-04T21:48:00.000-06:00

Ok-- I've really wanted to share links that I think are really interesting. This will be something I do a lot. Eventually I'd like to gather these up in some kind of link catalog-- but one that has high quality links only.

Here are a few that I check regularly that I highly recommend:

www.spaceweather.com NASA site that provides daily updates as to what is going on up there!
www.rc-astro.com Amazing astrophoto site of an astronomer that lives in my neighborhood. He's won awards and been published lots of times in Sky & Telescope (a famous astronomy magazine) as well as in other places. And no, I don't even know him, I just like his site.
sci.astro.amateur The usenet newsgroup where I learned a lot of up to the minute astronomy info! There are a lot of experts out there on this newsgroup! One piece of advice: search for your answers before asking questions that may not need to be asked.
Astronomy Picture of the Day A beautiful site with wonderful pictures updated every day! What more could you want?
Sky and Telescope Ok-- so it's a magazine website-- but they have minimal ads and it's pretty good for up to minute news and articles. And you don't need a subscription!

One thing: I won't post links that have pop-ups or a lot of advertising on it-- it's just annoying.

More to come!

Hello world!

2004-11-04T21:19:00.000-06:00

I guess that's what you say when you start a blog for the first time.

I've created this one to be able to post stuff I find related to my favorite hobby: Astronomy. But, I want to do it differently than the way astronomy is usually presented, and I hope to do that in this web log format.

So come and enjoy my observations of the sky-- and learn about fun facts just as I do!

-- Dan