The sky is falling...again, 10.21.11

Not only is another meteor shower coming this way, but yet another gargantuan satellite is making its way back to Earth this weekend.

The Orionids meteor shower began about three or four days ago, and will continue to build until its climax on the morning of October 22^nd, just before sunrise. Called the “Orionids” because the meteors seem to be falling out of the constellation Orion the hunter, the bright streaks and fireballs are actually created by detritus from Halley’s comet, burning up in our atmosphere.

Like a trail of fairy dust behind the Pigpen of fairies, the comet leaves a long, filthy (but sparkly—it is mostly ice) trail behind it. When Earth passes through the trail of dirt, dust, and ice, the resulting friction created by the pieces scrubbing against our atmosphere causes them to burn up.

Do not expect the meteor shower to blow you away, though. The Orionids is only expected to produce about 20-25 meteors per hour. In the past, the Orionids have also been very dim, so do not expect to see any if you are in an urban area with lights on at night. The best place to observe a meteor shower (or anything in astronomy, really), is to find a safe, dark, wide-open field in a rural area. The less light from nearby cities and towns you see on the horizon, the better. The Orionids are perfect for a nice calm, quiet evening of sky watching.

You may also want to keep an eye out for ROSAT, the 2.7-ton German X-ray satellite. Remember UARS, which fell to its death in the Pacific Ocean late last month? Well, it seems another one of the mechanical behemoths has bit the dust and is in the process of winding its way down to Earth.

Unlike UARS, which mostly broke up or burned up in our atmosphere, ROSAT is expected to have over 1 ton of its pieces survive reentry into Earth’s atmosphere. While the chances for getting hit by it are higher than they were for UARS, they are still only about 1 in 2000. It may look great if you happen to catch a glimpse of it through a nice pair of binoculars, but the odds are far against it doing any real damage.

While it is impossible at this point to predict exactly when or where ROSAT will make its final resting place, scientists do guesstimate this it should make landfall over the weekend, either Saturday afternoon or Sunday morning. The best predictions they can manage are about 5 or 6 hours before it hits the ground.

Credit: SPACE.com. 

Secret satellites, 04.18.11

It goes without saying, but the Pacific Ocean is huge. So, it would make an excellent place to "de-orbit" classified government spy satellites, says Ted Molczan of Toronto, an expert satellite tracker and part of a global sky watching effort.


Lacrosse 2, a classified government spy satellite, is one of five extremely large instruments used to take special radar images- even through clouds. Supposed to be a secret, the Lacrosse 2 is covered in "gold-colored kapton insulation blankets," which makes it reflect light with an "orange-red hue." This not only makes it easy to spot with a decent telescope or binoculars, but also plain pretty to look at for sky watchers. Whoopsie. So much for secrets.

So, when reports slowly started coming in from around the world in March that the Lacrosse 2 had gone MIA, the hunt to spot it again began in earnest, but to no avail. While it is possible that the gigantic satellite had been drastically maneuvered to another orbit, that is not probable, said Molczan. According to him, big orbital changes usually are not made by such huge satellites. Molczan theorizes that the satellite was “de-orbited” back to Earth, most likely a remote region of the Pacific Ocean, where any surviving pieces could be recovered by reconnaissance teams.

So why carefully plot and direct their path instead of just dropping them to Earth or leaving them floating about in space? Well, they are spy satellites after all; to just drop it could compromise national security, according to Molczan. It would not be surprising if Lacrosse 2 had been retired, though; it has been in orbit for an astounding 20 years. The model depicted here is probably similar to the Lacrosse 2, according to SPACE.com.

Image credit: National Reconnaissance Office (NRO).

Credit: SPACE.com. 

Asteroid Apophis a threat in 2029? 03.14.11

Astronomers have been tracking a 900-foot wide rock that is hurtling towards earth. Will it strike us? Only the math can tell.

Image credit: SPACE.com.

Photographed on January 31, astronomers said on March 9 that this was the first clear shot they have been able to take of the approaching asteroid in at least 3 years. The photo was taken from atop one of Hawai’i’s dormant volcanoes, Mauna Kea, using a telescope. It was originally thought that the rock had a 1-in-37 chance of hitting earth, but new calculations made the number grow substantially; it now has a 1-in-250,000 chance of dashing earth to bits. Oh, joy!


All of the calculations are made by doing some careful comparisons with the “known” distances of stars near the asteroid. As stars move very slowly, they can be fairly reliable space-scale distance markers, but the passage of time still has to be taken into consideration upon each new measurement. 


If it does not smash into earth in 2029, it should pass by again in 2036 and 2068. The pass in 2029 will likely alter its path, too, making it slide ever so much closer to earth. The pass in 2029, in fact, will most definitely be closer to earth than a lot of communications satellites are! You can expect to see Apophis without the aid of a telescope or even binoculars, weather permitting. Until then, all we can do is sit, measure, and crunch some more numbers.


Credit: SPACE.com.

Elusive Mercury visible this week, 09.17.10

Mercury, the planet closest to our star, the sun, will be visible until about Wednesday, the 23^rd, just before dawn. Mercury is in this prime viewing position only two times a year.


Most skywatchers never get to see Mercury because it is often obscured by the light from the Sun, but this week Mercury is just far enough away that it can be viewed in the eastern horizon just before sunrise, weather permitting.

Image credit: SPACE.com and Starry Night Software.

For the best opportunity at viewing Mercury, go to a place with a clear, unobstructed view of the eastern sky about half an hour before sunrise. Geoff Gaherty of Starry Night Education suggests using your fist as a measure of degrees to help locate Mercury. He says that a “human fist held at arm’s length covers about 10 degrees of the sky,” so hold your fist out just about the land’s horizon and look over the top of your fist to see Mercury. Binoculars are suggested to help you find it at first. If you are viewing Mercury with a telescope, it will appear in the shape of a crescent moon.


Credit: SPACE.com, Starry Night Education, Geoff Gaherty.