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Astronomers Detect Four Earth-Sized Planets Orbiting The Nearest Sun-Like Star (ucsc.edu)
Tim Stephens reports via The University of California in Santa Cruz: A new study by an international team of astronomers reveals that four Earth-sized planets orbit the nearest sun-like star, tau Ceti, which is about 12 light years away and visible to the naked eye. These planets have masses as low as 1.7 Earth mass, making them among the smallest planets ever detected around nearby sun-like stars. Two of them are super-Earths located in the habitable zone of the star, meaning they could support liquid surface water. The planets were detected by observing the wobbles in the movement of tau Ceti. This required techniques sensitive enough to detect variations in the movement of the star as small as 30 centimeters per second. The outer two planets around tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets.
Fir those who wonder, 30 cm/s is roughly 10km/h, so about the speed of a jogger.
Interesting. When can we have a probe there to take a closer look?
Tau Ceti III is also known as Kaferia, home to the insectoid Kaferians.
Our best bet to get a closer look any sooner is to use our Sun as a gravitational lens. It is still a challenge, because we would need to put a telescope at the correct side of the Sun at about 550 AU, far beyond the orbit of Pluto, but it is much closer to our technological reach than actual interstellar probes. NASA is thinking about this project: https://www.technologyreview.c...
Wow, it appears like we are really getting close to being able to answer the question: are we alone in the Universe?
I'm amazed that they were able to detect the "wobbles" using (relatively) inexpensive ground-based telescopes. Just a little bit of improvement and they'll be able to detect earth sized planets (although maybe 1.7x mass isn't too bad; I think the surface gravity might be just a little higher depending on the density).
Soon, a space based telescope (the James Web ST?) may, with these super-sensitive instruments, be able to take the next crucial step and determine the composition of their atmospheres. If they detect free oxygen or other products of biological (or even industrial!) by-products, we'll know that there's life elsewhere in the universe! Maybe we'll find out sooner this way than a similar positive result coming from a probe we send to Mars, Europa, Enceladus or Titan.
Of course, although I'm hoping that we'll see a biological signal, I really really doubt we'll see something that is the product of a technological civilization. Unfortunately, we still don't know the answer to Fermi's paradox. (I really wish the Chinese would take their new giant radio telescope and dedicate it to looking for signals). Until we hear from someone; we'll have to assume that maybe (intelligent) life in the Universe is rare.
I hope it's not because intelligent life usually kills itself off (like we seem to be doing: https://www.nytimes.com/2017/0...
Full disclosure: in my partially misspent youth I worked on S.E.T.I. :)
Because that's where Durand Durand hides!
So any planet detected outside our solar system that just happens to be around the size of our own is deemed an "Earth" planet now?
"probably reduces their habitability due to intensive bombardment by asteroids and comets. "
So lots of more water and minerals raining down from the sky.
Good business in the future.
Yay! We have somewhere to go when Earth is totally trashed!
Damping absorbs vibrations. Dampening is caused by moisture.
FTA:
Unlike more common smaller stars, such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked,
What does size/brightness have to do with it? Pluto isn't tidally locked to the sun...
KAAAAAAHN!......KAAAAAAHN!
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This one for example.
Starshade
. . . and re-use the mass to create something akin to an Dyson Sphere. I'd suggest a Ringworld, but the mechanical properties of Niven's "scrith" simply aren't possible, at least with any level of material science we currently have or are likely to have. . .
Just gotta be. Too soon?
I would like to see a project to begin firing off "seed bags" to every planet we can point a barrel at. Sure, most won't survive but it very well may be one way we can tell what is out there way down the road.
Suppose we found say, these 4 rocky planets, but life hadn't been kickstarted. It seems like it would be our duty to help them thrive. Within 100 years of crash down, we could theoretically see the possible beginning of a planet that could host life like ours.
By searching the cosmos, over the thousands of planets we "seeded", we then could narrow down our search for "habitable" planets by simply looking at the atmosphere, vs. trying to get a close up picture of alien ants. This would certainly shorten the time to search for a planet to use as a base for further exploration.
If life is so different, there may not be any collateral damage to another planet. All of the other planets do not need to be "spared" human involvement. Save a few for the scientists and lets begin colonization on the microbial level.
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To Infinity and Beyond! - B.L.
I wonder about the definition of "sun-like star". Alpha Centauri is much closer than Tau Ceti, and it is almost a twin of the Sun. On the other hand, Alpha Centauri is part of a triple-star system, and Tau Ceti is a lone star, like the Sun. Take your pick!
"...probably reduces their habitability due to intensive bombardment..."
This puts this system into the same portion of system lifecycle as our Solar System's Late Heavy Bombardment. This is not "reduced habitability", this is "no habitability".
An LHB regularly melts the entire surface of the planet, the impacts are so severe. It is astonishing to suggest that there is any niche for life, at all, under such circumstances. How about a moon of the planet though? No, any moons would be subject to the same bombardment. In fact impacts may be with objects the size of moons or even planetismals. Such impacts could destabilize a moon's orbit causing yet more chaos and destruction.
An LHB phase is bad news for life no matter how you cut it.
We are only getting close if we aren't alone in the universe AND if life isn't rare.
It is pretty hard to prove we 'are alone', so believing we are not is more an act of faith then anything else, until there is evidence. Of which we only have suggestive not positive evidence.
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