Tag Archives: astronomy

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Detecting vegetation, analyzing atmospheres on extrasolar planets

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sodiumlinesWe know there are lots of planets orbiting other stars: we’ve found more than 250 of them already, and we’re getting better at finding them all the time. But the big question is, do any of the obviously plentiful extrasolar planets in the galaxy support life?

So far, we can’t tell: but we’re getting closer to being able to. Dr. Luc Arnold of the CNRS Observatoire de Haute-Provence in France thinks we might be able to tell if an extrasolar planet supports vegetation via a spectral analysis of the light reflected off it, because vegetation absorbs a lot of light around a specific wavelength for use in photosynthesis (on Earth, that’s red light, so this phenomenon is called the Vegetation Red Edge).

We don’t have any Earth or space-based telescopes that are able to carry out spectral analysis fine-grained enough to do this, yet, and even ESA’s Darwin and NASA’s Terrestrial Planet Finder, launching within the next decade or so, won’t be able to–but the next generation of planet-finding spacecraft after that probably will be.

One thing we have managed to do, though, is analyze the atmosphere of an extrasolar planet: a "hot Jupiter" orbiting a star in the constellation Vulpecula. By measuring which wavelengths of light from the planet’s star are absorbed by its atmosphere every time it swings between the star and Earth, University of Texas at Austin astronomer Seth Redfield determined the planet’s atmosphere contains sodium. (Via Universe Today and Universe Today.)

Again, we’re a long way from using the same technique to look for oxygen–a strong indicator of Life As We Know It–in Earth-sized planets’ atmospheres. But it’s likely just a matter of time. (Illustration: S. Redfield/T. Jones/McDonald Observatory.)

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A Personal Note: I apologize for a lack of posts from me over the past little while. As Paul mentioned in his last Friday Free Fiction post, I’m currently in rehearsal for a professional production of Beauty and the Beast, and it’s taking up most of my time. I hope to still manage an occasional post, though, until the show ends December 30, and resume regular posting in the new year.

[tags]astronomy, extrasolar planets, extraterrestrial life[/tags]

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Telescope finds a void in the universe

The central darker region of the middle of this picture indicates something very strange is occuring…Following on from yesterday’s post about Hugh Everett and the ‘Many Worlds Interpretation’ of Quantum Physics, I came across this interesting article via Chris Mckitterick’s blog. NASA’s Wilkinson Microwave Anisotropy Probe(WMAP) has been studying the microwave emissions of the universe back towards the big bang. The Cosmic Microwave Background, or CMB, is more or less constant across the sky, a gradually cooling remnant of the beginning of our universe.

Earlier this year a vast region of space was detected where the CMB was a lower temperature. Further study showed that the area had very few stars or galaxies and was a much bigger empty space than predicted by any models. Some scientists think the hole is caused by a massive patch of dark energy. Others think that this region may be evidence of another universe, especially if a similar patch is found in the southern hemisphere of the sky.

[via Chris Mckitterick, image from Science Daily]

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Oops, our bad: by observing the universe, we may have doomed it

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DarkMatterPie-590 One of the weirdest aspects of quantum theory is the role of the observer: particles exist only as probabilities until they are observed, at which point they become definite. (Schrödinger’s neither-alive-nor-dead cat is the most famous thought experiment along these lines.) (Via EurekAlert!)

Now New Scientist is reporting that a pair of physicists at Case Western Reserve University in Cleveland, Ohio, suggest that when, in 1998, astronomers observed the light from supernovae and from that deduced the existence of dark energy, we may have reset the clock of the university universe to the state it was in early in its history, when it was more likely to just as suddenly cease to exist as it suddenly sprang into existence in the first place. (Image: NASA via Wikimedia Commons.)

We’re still here, so the universe hasn’t winked out of existence just yet. But any second now…

[tags]cosmology, astronomy, physics, quantum theory[/tags]

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A braw bricht moonlit nicht is a rare thing in the universe

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Earth and Moon New observations from NASA’s Spitzer Space Telescope suggest that moons like Earth’s are rare across the universe, occurring in only five to 10 percent of planetary systems at most. (Via Science Daily.)

The observation is based on the belief that the moon was born when the infant Earth was clobbered by something the size of Mars (shades of Velikovsky, except he had collisions like that that happening in historical times). Astronomers don’t see the amount of dust around other stars they would expect to see if those types of collisions were common.

This could have an impact on the likelihood of land-based life on other planets, since life may have moved from the ocean to the land on Earth due to the tides the moon induces. And here’s another question: would we have dreamed of travelling to other worlds if we hadn’t had one hanging so conveniently close in the night sky? Without a moon, would other civilizations ever develop space travel? (Image: NASA.)

Here’s an even more alarming thought: without a moon, think how differently science fiction would have developed. It might not even have developed at all.

And worse yet, what would songwriters have done without a moon to rhyme June with?

Why, the mind boggles.

UPDATE: Here’s an article from Astrobiology Magazine examining what Earth would be like "If We Had No Moon."

[tags]moon,astronomy,NASA[/tags]

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New supernova changes the way astronomers think about star explosions

supernovas are one of the most incredible sights in the universeEarlier in the year a gigantic explosion lit up the sky. Supernova SN 2006gy, around 100 times brighter than a typical example, created a real puzzle to astronomers – how did such a big event occur? Currently there are two main models for Supernovae – type I occur when a white dwarf accretes too much material from another partner star and crosses the unstable Chandrasekhar limit, forcing nuclear fusion in the core. The second principle type, type II has a larger older star running out of hydrogen in its core to burn, leaving the outer layers cooling and falling inward. When the pressure from the infalling layers gets high enough, the helium ignites – a type II supernova.

The sheer brightness of SN 2006gy doesn’t fit any current theories, and has left astronomers baffled. A new model suggests that the star exploded not once but twice or as much as SIX time, with the outward material from later novas hitting earlier remnants to create the bright lights in the sky. A somewhat similar star, Eta Carina, is not too far off exploding in our own galaxy, which should provide an amazing night show.

[story and image via Science Daily]