Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

nature.com

Post reply on HN
Print view View original

21–30 of 754 posts

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

#21

Post by vkou »

ionwake wrote: post #5
bcaulfield wrote: post #2

Let's go

It's a Trap ;) On a serious note, if we can travel close to the speed of light , say 95%, using for example, nuclear rockets, how long would it take to arrive ? ( from the travellers perspective )

At a constant 1g of acceleration, you could travel there, from the traveler's point of view, in ~2-3 years. (And in ~40 years from a stationary observer's point of view.)

Mind you, a constant 1g acceleration (Or accelerating any human-carrying spaceship to relativistic speeds, really,) is about as plausible as a spaceship driven by pixie dust and unicorn farts.

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

#23

Post by bpodgursky »

kchoudhu wrote: post #14
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…

Is this an orbitally stable arrangement?

Yeah, they are all resonant.

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

#24

Post by 6502nerdface »

> Gillon says that the six inner planets probably formed farther away from their star and then migrated inward. Now, they are so close to each other that their gravitational fields interact, nudging one another in ways that enabled the team to estimate each planet's mass. They range from around 0.4 to 1.4 times the mass of the Earth.

Given that these planets are so close to each other, and interacting with each other gravitationally, how likely is it that their orbital arrangement is stable over geological time?

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

#25

Post by cgriswald »

jff wrote: post #18
petrikapu wrote: post #12

Three of those discovered planets are in habitable zone https://www.dropbox.com/s/bdeog7ta7i4rb7c/alien%20planets.pn...

Are you basing that statement purely on the appearance of the planets in the artist's conception you linked, or was it stated in another article somewhere?

It was stated by the scientists at the NASA press release. They also stated that all seven of the planets have the potential for liquid water depending on (unspecified) circumstances.

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

#26

Post by batbomb »

rubicon33 wrote: post #9

I was reading up about earth alternatives recently, and upon realizing the distance was always going to limit us, no matter how perfect the planet, I realized we need to travel at the speed of light. I think our "best shot" at that right now, is to digitize humans. If we could store consciousness in binary, we could then transmit it at the speed of light (like we do with data every day!). You'd need a receiver on the…

I think the magic speed is actually 10% the speed of light.

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

#27

Post by imglorp »

NickBusey wrote: post #13
rubicon33 wrote: post #9

I was reading up about earth alternatives recently, and upon realizing the distance was always going to limit us, no matter how perfect the planet, I realized we need to travel at the speed of light. I think our "best shot" at that right now, is to digitize humans. If we could store consciousness in binary, we could then transmit it at the speed of light (like we do with data every day!). You'd need a receiver on the…

Why not just make that first payload contain actual humans? Seems a helluva lot simpler.

Yup, for several hundred thousand year's journey. No problem. :-)

I would just hope my emacs session will stay up that long.

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

#28

Post by petrikapu »

jff wrote: post #18
petrikapu wrote: post #12

Three of those discovered planets are in habitable zone https://www.dropbox.com/s/bdeog7ta7i4rb7c/alien%20planets.pn...

Are you basing that statement purely on the appearance of the planets in the artist's conception you linked, or was it stated in another article somewhere?

It was said by one of the scientist in live Nasa TV broadcast https://www.nasa.gov/multimedia/nasatv/

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

#29

Post by robin_reala »

rubicon33 wrote: post #20
NickBusey wrote: post #13

Earlier quoted context omitted.

Why not just make that first payload contain actual humans? Seems a helluva lot simpler.

You could, and probably would. But, how would you send everyone else? That 'traditional' method (carbon based fuels to propel a heavy payload) is extremely expensive, and slow. So if you ever wanted to send more than just 1 payload, you'd quickly reach resource limitations (namely cost, and time).

Why would you need to send more? Humans are natural von Neumann machines.

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

#30

Post by rm_-rf_slash »

ionwake wrote: post #17
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…

Out of interest , although dimmer, are there any potential hazards simply due to the proximity of a dim star?

Actually they are fewer. A dim star has less high energy radiation and a lower probability of harmful solar flares.
Post reply on HN