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Seven earth-sized planets discovered circling a star 39 light years from Earth

nature.com

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Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#351

Post by joeyspn »

h4nkoslo wrote: post #41

Uh oh. The "great filter" hypothesis is essentially that the rarity of intelligent life has to be explained by some parameter of the Drake equation, and that whatever the "small" parameter is is either in our past or in our future. If the "great filter" is the rarity of habitable worlds, then clearly we don't need to fear it, since we already found one. But if habitable worlds aren't rare, then it's more likely it li…

The "Transcension Hypothesis" is a possible solution to the Fermi Paradox...

http://www.sciencedirect.com/science/article/pii/S0094576511...

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#352

Post by [deleted] »

tajen wrote: post #339
sand500 wrote: post #192

Earlier quoted context omitted.

If you go fast enough doesn't any incoming radiation just get blue shifted into gamma rays? Just running into cosmic dust at the speed of light would not be fun.

Isn't that the whole relativity theory: that if you emit a photon while at celerity 1c, it looks like it goes away at 1c both from you and from a still reference? hence blue is still blue at 1c?

[deleted]

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#353

Post by perlgeek »

biot wrote: post #210
JumpCrisscross wrote: post #92

Earlier quoted context omitted.

> it's difficult to constrain the life of the long-lived ultraviolet dwarf stars What's the upper bound on their estimate for TRAPIST-1's age?

The upper bound is the age of the universe.

This may sound a bit snarky, but it's actually quite a good boundary.

Current estimations for the age of the Universe are around 12 to 14 billion years, which isn't much compared to a trillion year life span of such a star.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#354

Post by dgudkov »

sampo wrote: post #223
r721 wrote: post #32

Wiki says "TRAPPIST-1 is an ultracool dwarf star that is approximately 8% the mass of and 11% the radius of the Sun. It has a temperature of 2550 K and is at least 500 million years old." https://en.wikipedia.org/wiki/TRAPPIST-1 Too young star for alien life hopes?

Earth is 4.5G years old, and the earliest undisputed microbial life fossils are 3.5G years old, so that gives 1000 million years. But we can also say that Earth was cool enough for liquid water 4.4G years ago, and there are some findings suggesting microbial life already 4.1G years ago. So only 300 million years, at maximum.

Moore's Law applied to DNA complexity hints that life could be way older than Earth itself: https://www.technologyreview.com/s/513781/moores-law-and-the...

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#355

Post by hulahoof »

mstade wrote: post #239
JumpCrisscross wrote: post #34

Earlier quoted context omitted.

> are there...hazards simply due to the proximity of a dim star Tidal locking [1]. Similar to how our moon shines at us ass first all the time, the planets around TRAPIST-1 would be expected to have one face locked to their star. Instead of an equatorial belt bookended with loops of temperate zones, as we have on Earth, we should expect, climatically, an "equatorial" face and a "polar" face separated by a tropic-to-t…

Fascinating! Also – off topic, but – this description reminded me of Twinsun[1], the planet in the game Little Big Adventure. It remains one of my fondest game memories of that era, despite all its weird bugs. I've thought about finding a copy and playing it again at some point, but I fear it might spoil my good memories of it.. [1]: http://lba.wikia.com/wiki/Twinsun

For what it's worth I did this a few years ago and was not disappointed - great to hear other people grew up with this game too!

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#356

Post by hughes »

rlanday wrote: post #349

Now technically, according to the International Astronomical Union, these bodies can't be planets since they don't orbit the sun: https://www.iau.org/static/resolutions/Resolution_GA26-5-6.p... "1. A planet is a celestial body that (a) is in orbit around the Sun" Makes me wonder how much this definition of a planet was motivated by the desire to be able to give elementary schoolers a nice small set of things to memor…

Are you saying that they don't orbit their star because some of them gravitationally influence each other?

Or are you saying that nothing outside of our solar system can be a planet?

Either way, NASA should schedule another press release about taking celestial pedantry to a new level.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#357

Post by hackuser »

flexie wrote: post #194
_lbaq wrote: post #131

Earlier quoted context omitted.

Very likely, since this happens between Mars and Earth: https://en.wikipedia.org/wiki/Martian_meteorite

Fascinating! Would vira or bacteria beable to survive travelling from Earth to Mars in or on a rock or vice versa?

IIRC, that is a serious hypothesis for how life began on earth, seeded from elsewhere (maybe not Mars).

But certainly someone here knows more than I do about it ...

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#358

Post by rorosaurus »

matwood wrote: post #298
ryandrake wrote: post #234

Earlier quoted context omitted.

To put that 60 years into perspective: It was 66 years between the first powered airplane flight and landing people on the moon.

These kinds of realizations make me sad that life is so relatively short.

It's also exciting, isn't it? That every generation is likely to experience some unique achievement?

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#359

Post by hackuser »

pcrh wrote: post #185
personlurking wrote: post #140

Earlier quoted context omitted.

> If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds... Makes me think of the film Another Earth http://imgur.com/a/01xlN

Melancholia by Lars von Trier is another great movie about the earth colliding with another planet. http://www.imdb.com/title/tt1527186/

An excellent, incredibly beautiful film, beyond the topical plot point.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#360

Post by kitrose »

cletusw wrote: post #7

Apparently finds are close enough to us that we should be able "to follow up, to see, for example with the James Webb Space Telescope that we're going to launch [next] year, the atmospheres and also to look at bio-signatures, if there are any" !

Can someone explain to me why we don't replicate some of these key platforms like the Hubble and James Webb ST?

It seems like the major limitation for discovery is getting enough observation time for whatever certain point in the sky that scientists are researching.

Why don't we launch a second copy of James Webb?

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