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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

#381

Post by Symmetry »

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?

The spectrum of light depends on the frequency of the vibrations in the electromagnetic field, not the velocity of the wave. For both red and blue light the wave is traveling at 1c but the peaks of the wave are at 700 nanometers or 400 nanometers depending on the color. And under Special Relativity distances distort so that you do in fact see light shifted to higher frequencies/shorter wavelengths in the direction you're traveling.

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

#382

Post by ar15saveslives »

semaphoreP wrote: post #200
coryfklein wrote: post #149

I'm having a hard time finding more data on the density of matter in interstellar space. Wikipedia says > The density of matter in the interstellar medium can vary considerably: the average is around 10^6 particles per m3 but cold molecular clouds can hold 10^8–10^12 per m3 [1] But I imagine that interstellar gas would be easier to fly through than interstellar sand. Do we know the composition of matter in interstell…

It's almost all Hydrogen/Helium gas. Other larger atoms and molecules are known to exist in the interstellar medium, but it's primary gas. Also, a good way to remember the density is ~1 Hydrogen atom per cm^3.

We could catch it and use as a fuel or recoil mass!

(does napkin math)

Nope :-(

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

#383

Post by bcaulfield »

personlurking wrote: post #140
dmix wrote: post #6

My favourite part of the press release: > The planets also are very close to each other. 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, which would sometimes appear larger than the moon in Earth's sky. > In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water cou…

> 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

Except with multiple planets?

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

#384

Post by pwython »

kitrose wrote: post #360
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?

A Hubble or James Webb is easily a billion dollar effort, making it THE major limitation for discovery. No one is investing that sort of money for no return. Honestly, even if they did, it would be frowned upon considering the more important humanitarian investments at hand.

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

#385

Post by Symmetry »

wallace_f wrote: post #260
chris_va wrote: post #204

Earlier quoted context omitted.

You are technically travelling at 99.99999% of the speed of light right now, relative to something.

What determines my speed limit? Is it set at 0 here on earth? What if I travel to another galaxy, this one was going at .5c relative to me when I was on earth. Then after trillions of years, inflation causes all of the galaxies to separate beyond sight from me in this new galaxy. Now, the centre of this galaxy appears at rest. Does my velocity get "reset?"

Special relativity says that no matter what your velocity is relative to Earth you can proclaim that you're actually at rest and it's the other guy that's moving. So your velocity is always continuously being "reset". And in each of the frames of reference of everything in existence nothing else is traveling faster than the speed of light.

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

#386

Post by mysterydip »

bcaulfield wrote: post #10
dmix wrote: post #6

My favourite part of the press release: > The planets also are very close to each other. 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, which would sometimes appear larger than the moon in Earth's sky. > In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water cou…

So, basically, this is cooler than just about any world that's been depicted in sci-fi.

One of the games I'm working on (a sci-fi mech and space combat action rpg) actually is set in a solar system like this. Cool to see one in reality relatively close by! I think it provides a lot of interesting situations allowing for basically a "space opera in a solar system".

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

#387

Post by [deleted] »

DougWebb wrote: post #272
dmreedy wrote: post #70

Earlier quoted context omitted.

I guess J.J. Abrams is somewhat forgiven for this, then: http://vignette4.wikia.nocookie.net/startrek/images/2/29/Vul... [edited for direct .jpg]

I always thought that Firefly's scenario of a bunch of Earth-like worlds in close enough proximity to have regular trading ships flying between them was unrealistic. Now, not so much. This system even fits in with the "Abandon Earth en-mass, move to new set of worlds" backstory. So, what did J.J. know, and when did he know it? And for that matter, how did he know?

[deleted]

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

#388

Post by RileyJames »

kitrose wrote: post #360
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?

It looks like the James Webb cost $8.7B to launch. The Hubble $4.7B at launch and $10B through till 2010. So it seems cost is the limiting factor. Replicas might be cheaper, but they wouldn't be kickstarter cheap.

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

#389

Post by jameshart »

dmix wrote: post #6

My favourite part of the press release: > The planets also are very close to each other. 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, which would sometimes appear larger than the moon in Earth's sky. > In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water cou…

Importantly, that means there is basically no way that a civilization that developed on such a planet would not at some point endeavor to travel to those other planets.

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

#390

Post by dwaltrip »

dwaltrip wrote: post #82
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?

In the Q&A session they said it's difficult to constrain the age of the long-lived ultraviolet dwarf stars once they finish the active early phase, as their lifecycle progresses so slowly. They live for more than a trillion years, compared to stars like our sun which are larger and burn through their fuel in less than 10 billion years. It's somewhat counterintuitive, but the bigger a star is, the faster it uses up it…

Typo: Ultraviolet should be "ultracool". Darn autocorrect
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