space

Mankind has always been driven by contradictory drives. The relentless curiosity that pushes us forward and is directly responsible for our progress from caves to cities. The fear of change that tells us "hang on, these caves/cities are really nice, we don't want to risk losing them." There isn't any greater potential threat to the status quo than the discovery of extraterrestrial life, which is why some people would prefer we didn't try.

There has been some outrage recently over attempts to contact intelligent aliens, where instead of hiding in the corner and listening real hard some astronomers beamed intense directional messages up up and away. Critics decried these actions as dangerous, though their fears reveal more about us than any eventual ETs. They assume that they would be similar to humanity, so their first response to finding a more primitive culture would be to exploit the hell out of it. While such a fate might be pleasingly ironic (for anyone who isn't human, at least), others contend that any species that can make the journey here has advanced to a point where their goals are rather higher-minded than "Shoot us".

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Most of the objections to contacting aliens are weak under close examination. We can't suddenly decide to hide after fifty years of pumping electromagnetic radiation into space without rhyme or reason - in fact, we'd better hope that an advanced civilization doesn't catch an episode of "American Idol" and just vaporize us outright. Suddenly keeping quiet would be like a drunk boyfriend carefully taking off his shoes after knocking over a bookshelf on his way to the bedroom.

Comet C/2007 N3 (Lulin), discovered in July 2007, should be the highlight comet of this season. It's predicted to reach about 5th magnitude in late February, so it should be easily seen in binoculars. It may even become detectable with the unaided eye in a dark, moonless sky.

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Lulin’s closest approach to Earth, 0.41 a.u. (61 million km), occurs on February 24th, when the comet may reach a peak of magnitude 5. By now it's visible in late evening (after rising around the end of astronomical twilight) and remains in view for the rest of the night.

And it's speeding along at just over 5° per day! That's about 1 arcsecond every 5 seconds of time, enough to show obvious motion during a short telescopic observing session. Similarly, that's 1 arcminute per 5 minutes of time if you're using binoculars.

President-elect Barack Obama will probably tear down long-standing barriers between the U.S.'s civilian and military space programs to speed up a mission to the moon amid the prospect of a new space race with China.

Obama's transition team is considering a collaboration between the Defense Department and the National Aeronautics and Space Administration because military rockets may be cheaper and ready sooner than the space agency's planned launch vehicle, which isn't slated to fly until 2015, according to people who've discussed the idea with the Obama team.

NASA seems thrilled.

As we head into the traditional western Holiday Season, I'd like to present this Hubble Space Telescope imagery Advent Calendar. Every day, for the next 25 days, a new photo will be revealed here from the amazing Hubble Space Telescope. As I take this chance to share these images of our amazing Universe with you, I wish for a Happy Holiday to all those who will celebrate, and for Peace on Earth to everyone

I haven't gotten an advent calendar since I was a teenager, my grandparents used to give me one every year with German writing on the back.

This month marks the 10th anniversary of the first launched module of the International Space Station (ISS). The module Zarya was lifted into orbit on November 20th, 1998 by a Russian Proton rocket lifting off from Baikonur, Kazhakstan. In the decade since, 44 manned flights and 34 unmanned flights have carried further modules, solar arrays, support equipment, supplies and a total of 167 human beings from 15 countries to the ISS, and it still has a ways to go until it is done. Originally planned to be complete in 2003, the target date for completion is now 2011. Aside from time spent on construction, ISS crew members work on a good deal of research involving biology and physics in conditions of microgravity. If humans are ever to leave the Earth for extended periods, the ISS is designed to be the place where we will discover the best materials, procedures and safety measures to make it a reality. (32 photos total)

There are two distinct types of astrophotography which require two different approaches.

First is deep sky. This includes all galaxies and nebulas, even comets. Generally what are called "faint fuzzies". For those objects, long exposures are pretty much a must, so video will not work. In that case, taking multiple stills at shutter speeds in the order of minutes each is the way to go. There are many things involved in terms of equipment and technique (besides just the scope and camera), best bet is to join an astro forum (CloudyNights is a very good one imo) and get advice there.

Second is planets/moon. Since these abjects are relatively bright, long exposure is not needed nor wanted. As Rick mentioned (and I defer to Rick, imo he's one of the most knowledgeable astro imagers on here), seeing conditions become the most important factor here. The longer your focal length, the more important that is. To combat it, the best way in amateur astronomy (besides moving, lol) is fast shutter speeds. Just like taking pictures of moving objects, the faster the shutter, the better it freezes motion, in this case the wobbling of the image due to optical turbulence. Stacking the best frames (and choosing the reference point(s) to align the frames) will result in the sharpest image. In this case, video is your best option.

As I mentioned in answer to Victor's comment, on some planets like Jupiter, you only have a very short time to take all your frames or video to stack into one image. Trying for longer will result in additional blurring of the image due to the planet rotating. So, to maximize the number of frames (more frames will help with noise as well, also very important), and to minimize other sources of blurring (from the shutter), video will yield the best results. This is why all serious astronomers use variants of video cameras to take images of planets and moon.

"It must be ice," said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice. There had been some question whether the bright material was salt. Salt can't do that."

The chunks were left at the bottom of a trench informally called "Dodo-Goldilocks" when Phoenix's Robotic Arm enlarged that trench on June 15, during the 20th Martian day, or sol, since landing. Several were gone when Phoenix looked at the trench early today, on Sol 24.

It could be something else, but ice sounds like a pretty good guess.

NASA's Phoenix spacecraft landed in the northern polar region of Mars today to begin three months of examining a site chosen for its likelihood of having frozen water within reach of the lander's robotic arm.

Radio signals received at 4:53:44 p.m. Pacific Time (7:53:44 p.m. Eastern Time) confirmed the Phoenix Mars Lander had survived its difficult final descent and touchdown 15 minutes earlier. The signals took that long to travel from Mars to Earth at the speed of light.

Hooray!

Senior Review and rankings for the ten missions under evaluation for NASA Astrophysics in 2008 have been published.

1. Swift
2. Chandra
3. GALEX
4. Suzaku
5. (Warm) Spitzer
6. WMAP
7. XMM
8. INTEGRAL
9. RXTE
10. Gravity Probe-B

Bottom line here is that NASA funds are too tight, so some operating missions are being reviewed for descoping or shut down.

The new test of general relativity concerns a distant galactic core or quasar called OJ287, which is known to emit a pair of bright optical bursts every 12 years or so. In 1988, Valtonen and others suggested that this emission is powered by a primary black hole 18 billion times more massive than the Sun, around which orbits a second black hole some 200 times lighter. In such a binary system, the lighter object passes through matter in the accretion disk of the primary black hole twice per orbit, releasing a burst of energy each time it does so.

By modelling such a system, researchers could then put general relativity to the test by predicting when the next burst should occur. At the time, the next major bursts (which were due in the mid 1990s) could only be predicted with an accuracy of a few weeks, which was too vague to test general relativistic effects. But early last year, based on refined models and years spent monitoring OJ287, Valtonen and others were able to predict the date on which the next bright pulse should appear: 13 September 2007, give or take a day or two.

To have any hope of detecting the pulse, more than 25 astronomers from 10 countries had to work together. This is because in September OJ287 rises in the east just before sunrise, and is therefore only visible at any one location on Earth for about 30 minutes before the sky becomes too bright. By starting observations in Japan, followed by China, Europe and ending in the Canary Islands, observers were able to follow the sunrise westward around the globe and maximise observing time. In total, about 100 measurements were made between 4 September and 20 October, some of which by amateur astronomers.