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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

#341

Post by ttam »

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

I was gonna say this.

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

#342

Post by bryondowd »

purple-again wrote: post #227
criddell wrote: post #168

Earlier quoted context omitted.

That's essentially what blueprint said. You didn't have any trouble figuring out what blueprint was saying, right?

What's wrong with begs the question? It's a regular part of my vocabulary and I'm a southern American.

I think this article sums it up:

http://www.quickanddirtytips.com/education/grammar/begs-the-...

tldr: Begs the question is a formal term for when a conclusion is not supported by given arguments. Using it the way most people do is technically incorrect, but has become common enough that it is in the gray area where one can consider it the new correct usage.

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

#343

Post by ttam »

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/

Yeah, but Another Earth's main character is fascinated by astronomy and gets accepted to MIT

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

#344

Post by semi-extrinsic »

blueprint wrote: post #326

Physicists have got blinders on. Once we solve the gravity problem everything changes. I've been searching for a decade for scientists who can confirm my info but tbh most everyone seems to have abandoned themselves already.

> Once we solve the gravity problem

I have a feeling I'm going to regret asking, but here we go: what "gravity problem"?

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

#345

Post by tokipin »

stupidcar wrote: post #87
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?

Well, it's "at least" 500m, but is probably much more[1]: "Determining the ages of such small stars is difficult because they evolve so slowly over their lifetimes of trillions of years but it is estimated to be in excess of a half a billion years and is probably much more." And abiogenesis occurred on Earth within about 500m years of the Earth's formation, so life can clearly arise pretty quickly. It's complex, mult…

I'd be surprised if there isn't other microbe-like life in our own solar system. And the path from microbial to "complex" life is just a matter of whether the environment provides enough energy to support it (nearby sun + photosynthesis in our case). This is because cellular communities will always have certain niche advantages (homeostatis etc).

Complex life developed on Earth because it is advantageous in a physics/evolutionary sense, not because the universe accidentally slipped on a banana. Complex life is only an "accident" in that the search algorithm took a while to find the maxima. Otherwise it's just a matter of running the search long enough, and for that all you need is a star.

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

#346

Post by dgudkov »

DanBC wrote: post #44
e0m wrote: post #33

To get a spacecraft there it would take: Accelerating at 1g the 1st half, and decelerating at 1g the 2nd half, the traveler would experience 7.3 years of time. For observers it would take 41.8 years at a max speed of 0.998c If you had a near perfect hydrogen -> helium fusion engine, it'd take about 6 million tons of fuel (about the mass of the Pyramids of Egypt or 2,000 Saturn V rockets)

How much fuel would it take to get 6 million tons of fuel off Earth into the interstellar ship?

The best way would be to use a space elevator pipe for this. But it's still not feasible.

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

#347

Post by gozur88 »

JumpCrisscross wrote: post #34
ionwake wrote: post #17

Earlier quoted context omitted.

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

> 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…

It's not a given, though. We used to think Mercury is tidal locked, but that turns out not to be the case. These planets, as I understand it, are in similar orbits, so they may not be locked either.

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

#348

Post by civilian »

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

You can pick up Relentless on GOG :] https://www.gog.com/game/little_big_adventure

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

#349

Post by rlanday »

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 memorize.

Edit: actually I might be incorrect about this, the resolution is titled "Definition of a Planet in the Solar System", I'm not sure the IAU actually has a definition of what a "planet" would be outside the solar system, but they may be open to the idea that they exist :)

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

#350

Post by sand500 »

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?

I'm talking about radiation from other stars or what ever. Imagine if every star in the star field in front of you shifted from visible light to gamma.

I'm sure there is a study out there that describes the exact amount of radiation exposure you would receive at reletivistic velocities due to blue shifting.

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