Today, SpaceX expects to launch a Falcon 9 rocket to deliver NASA's Transiting Exoplanet Survey Satellite (TESS) into orbit. Scientists expect TESS to find thousands of exoplanets by detecting when they pass in front of their host stars, briefly blocking the light of those suns.
“A few months after TESS launches, we will be able to point out the first ones of these familiar stars, which host planets that could be like ours,” says Cornell University astronomer Lisa Kaltenegger, director of the Carl Sagan Institute.
From Nadia Drake's excellent FAQ on TESS in National Geographic:
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The search for life beyond Earth is necessarily constrained by what we know. Life as we don’t know it could be anywhere, and it doesn’t care that we haven’t deigned to imagine it yet. To help focus the hunt, astronomers are starting by looking for something familiar. And we know that at least once, life evolved on a warm, rocky planet orbiting a relatively stable star.
That being said, many of the stars TESS will scrutinize will be smaller and dimmer than our own: the cool, reddish M dwarfs that are the most common types of stars in the Milky Way. Planets orbiting these stars at a distance that’s neither too hot nor too cold for liquid water to exist are going to be snuggled in quite close—orbiting near enough to their stars for scientists to find them on months-long time scales.
In addition, the worlds TESS expects to find will be better situated for observations that could reveal whether alien metabolisms are churning away on their surfaces, beneath their seas, or in their clouds.
Cold is easier to deal with than the raging heat of Venus. The Moon and Mars are bathed in dangerous radiation. This means Titan is humanity's best existential insurance policy. Charles Wohlforth and Amanda Hendrix, authors of Beyond Earth: Our Path to a New Home in the Planets, explain:
It’s cold on Titan, at -180°C (-291°F), but thanks to its thick atmosphere, residents wouldn’t need pressure suits—just warm clothing and respirators. Housing could be made of plastic produced from the unlimited resources harvested on the surface, and could consist of domes inflated by warm oxygen and nitrogen. The ease of construction would allow huge indoor spaces.
Titanians (as we call them) wouldn’t have to spend all their time inside. The recreational opportunities on Titan are unique. For example, you could fly. The weak gravity—similar to the Moon’s—combined with the thick atmosphere would allow individuals to aviate with wings on their backs. If the wings fall off, no worry, landing will be easy. Terminal velocity on Titan is a tenth that found on the Earth.
How will we get there? Currently, we can’t.
Oh well. Doom it is, then! Read the rest
Astronomers using NASA's Kepler Space Telescope and its extended K2 mission, as well as the W. M. Keck Observatory on Mauna Kea, Hawaii, have discovered the youngest fully formed exoplanet ever detected. Exoplanets are planets that orbit stars beyond our sun.
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We won't be colonizing this one first! Exoplanet HD189733b, previously determined to contain water in its atmosphere, is blasted by 2 kilometers-per-second winds, say researchers at the University of Warwick.
Twenty times faster than the highest wind speeds recorded on Earth, the 5,400 MPH gales are caused by the distant world's proximity to its star. Though sightly larger than Jupiter, it orbits 180 times closer, whirling around HD189733 at a distance of 2.8 million miles.
In our solar system, even baking-hot Mercury has 36 million miles between it and the Sun.
Temperatures on HD189733b are thought to exceed 1,800 °C, but the presence of water increases hopes that it will be found on more Earthlike worlds. Read the rest
Pluto haze! In my brain. Lately, things, they don't seem the same.
Space truth, more awesome than fiction.
WASP-19b is an exoplanet whose atmosphere is probably super hot and super poisonous — filled with methane and hydrogen cyanide instead of water. This video explains how astronomers can even begin to guess at the composition of the atmospheres of far away worlds. (Bonus: A soothing elevator music soundtrack!) Read the rest
The Kepler space telescope seemed doomed to become space junk back in August, when it lost its ability to accurately and reliably point in any particular direction. Now NASA has a plan that could allow the telescope to keep working, great news given the fact that all the rest of its hardware is still in good order. Excelsior! Read the rest
This rocky world, 700 light years away, might have been another Earth. Twenty percent wider, with not quite twice the mass, its density is almost the same. At just 1.5m kilometers from its star, however, Kepler-78b's surface roasts at a caustic 2,000 degrees Celsius and completes three orbits in every Earth day Read the rest
Can I interest you in a summer home on COROT-7b? Sure, the estimated surface temperature is 4,580 degrees F, the year is only 20 hours long, and it's probably just lousy with volcanoes. But, when it rains on COROT-7b, it rains rocks. No takers? Just in case, you should check out Lee Billings' slideshow on fantastically horrible planets. Read the rest
Later this month, scientists will start sending the first continuous mass hailing beacon into outer space — a sort of "Hey, you! Yeah, you! Here we are!" message that researchers hope will attract the attention of any intelligent life that happens to exist in the Universe. They're aiming it at the Gliese 526 system, about 17.6 light years away. It's worth noting that this is different than Gliese 581, a system you probably remember hearing about from the search for Earth-like planets. The two systems aren't even closely related. The name comes from a 1957 survey of (relatively) nearby stars. Read the rest
Before you get excited, please note that said planet is not actually made of beer. In fact, it's probably a gas giant, like Jupiter, only way hotter owing to the fact that it sits much closer to its own sun. BEER, in this case, is a somewhat tortured acronym for "relativistic BEaming, Ellipsoidal, and Reflection/emission modulations", a new method of finding exoplanets that could help us spot worlds we might otherwise have missed. Ian O'Neill explains at Discovery.com. Read the rest
Last week, Rob told you how scientists announced that they'd found two Earth-like planets orbiting the star Kepler-62. One of those, Kepler-62e, now ranks as the most Earth-like exoplanet we've ever found. Of course, all of this is relative.
What I like about this chart is that it kind of shows you how "Earth-like" doesn't really mean, "Man, that is totally exactly like Earth." Instead, you should translate it more as, "Welp, this is about the closest to Earth that we've found so far." Even Kepler-62e, as you can see, is much larger than the Earth and Mars. And size matters when it comes to actual habitability. As does density — and we don't know what Kepler-62e is made of yet. It's also worth noting that #2 on this list, the infamous Gleise 581g, is really a planet candidate, rather than a planet. We aren't actually certain it exists, just yet.
Popular Science has a neat little breakdown explaining what life might be like on Kepler-62e, if we could go there. But it's worth keeping the context in mind on these Earth-like planets. Don't pack your bags just yet. Read the rest
At his Psychology Today blog, Michael Chorost delves into a question about exoplanets that I've not really thought much about before — how easy they would be to leave.
Many of the potentially habitable exoplanets that we've found — the ones we call "Earth-like" — are actually a lot bigger than Earth. That fact has an effect — both on how actually habitable those planets would be for us humans and how easily any native civilizations that developed could slip the surly bonds of gravity and make it to outer space.
The good news, says Chorost is that the change in surface gravity wouldn't be as large as you might guess, even for planets much bigger than Earth. The bad news: Even a relatively small increase in surface gravity can mean a big increase in how fast a rocket would have to be going in order to leave the planet. It starts with one equation — SG=M/R^2.
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Let’s try it with [exoplanet] HD 40307g, using data from the Habitable Exoplanet Catalog. Mass, 8.2 Earths. Radius, 2.4 times that of Earth. That gets you a surface gravity of 1.42 times Earth.
... it’s amazingly easy to imagine a super-Earth with a comfortable gravity. If a planet had eight Earth masses and 2.83 times the radius, its surface gravity would be exactly 1g. This is the “Fictional Planet” at the bottom of the table. Fictional Planet would be huge by Earth standards, with a circumference of 70,400 miles and an area eight times larger.
Earlier this week, we learned that there is (most likely) at least one planet orbiting the star Alpha Centauri B. If you want to get really in-depth on this discovery, how it was made, and what it means, you should be reading Paul Gilster's Centauri Dreams blog.
I wanted to highlight this image, specifically, in order to quote some particularly evocative writing that Gilster posted yesterday. Cue the stirring music:
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When planet-hunter Greg Laughlin (UC-Santa Cruz) took his turn at the recent press conference announcing the Alpha Centauri B findings, he used the occasion to make a unique visual comparison. One image showed the planet Saturn over the limb of the Moon. Think of this as the Galilean baseline, for when Galileo went to work on the heavens with his first telescope, the Moon was visually close at hand and Saturn a mysterious, blurry object with apparent side-lobes.
Laughlin contrasted that with [this image], showing the Alpha Centauri stars as viewed from Saturn, a spectacular vista including the planet and the tantalizing stellar neighbors beyond. Four hundred years after Galileo, we thus define what we can do — a probe of Saturn — and we have the image of a much more distant destination we’d like to know a lot more about. The findings of the Geneva team take us a giant step in that direction, revealing a small world of roughly Earth mass in a tight three-day orbit around a star a little smaller and a little more orange than the Sun.