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

411–420 of 754 posts

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

#411

Post by rosser »

gydfi wrote: post #400
tajen wrote: post #318

Earlier quoted context omitted.

At that distance, gravity must be really fun. Tides are not only for water, such tides can also change the height of mountains, the balance of high-rise buildings, infer on volleyball rules, make you fart because of changes in atmospheric pressure, or... be leveraged to generate electricity. Those guys have simili-infinite energy at human scale.

Would they? I mean, we can see geological features on our moon, and our tides are orders of magnitude away from being rock-tearing events. I mean, the moon is small, but... how close do these planets approach, anyway?

Close enough that the perturbations these planets induced in one another's orbits allowed the team to estimate their masses at between 0.4 and 1.4 Earth-masses. In astronomical terms, that's very close.

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

#412

Post by fsloth »

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?

Roughly quoting Neal de Grasse Tyson: Since so many bacteria survive outer space there is a good chance it's because of - yes - survivor bias. If only because early earth was bombarded so often that fragments of the planet with microbes took of in a meteor strike and returned home after a while in space.

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

#413

Post by JesseObrien »

blueprint wrote: post #72
kcorbitt wrote: post #47

Earlier quoted context omitted.

That actually sounds... more plausible than I would have expected. Like, doable with technology I can imagine being within reach in the next 50 years even if we don't achieve any currently-unforseen breakthroughs.

Which begs the question, why haven't we at least even tried to have done anything like this already? Do we really need to repeatedly spend comparable amounts of money on yet another dramatic TV special about humans traveling to Mars, as narrated by a favored celebrity? We really are running out of time. And it almost seems like it's pre-determined to happen. :\

If you're curious on more than a surface level, this book is an excellent resource from an ex-astronaught on why things are lagging. "Safe Is Not An Option"

https://www.amazon.com/Safe-Not-Option-Rand-Simberg/dp/09891...

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

#414

Post by fsloth »

noobermin wrote: post #121
chrisabrams wrote: post #36

Earlier quoted context omitted.

I was essentially thinking the same thing. I wonder if an elevator could be built between all of them?

One of the callers (a biologist, so not a crackpot) on TV suggested that given how close the planets were, he wondered if it were possible for there to be cross contamination between the planets given how close they are to each other. He referred to them being part of the same "ecosystem." I'm not sure how feasible that is as a non-astrobiologist, but it is an interesting idea.

The survivability of several organisms has been actually tested https://en.wikipedia.org/wiki/List_of_microorganisms_tested_...

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

#415

Post by Arizhel »

blueprint wrote: post #374
semi-extrinsic wrote: post #344

Earlier quoted context omitted.

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

You're familiar with the fact that there is no proper, substantial, accepted model or principle of both gravity and EM that unify them, correct? And we don't knowingly have the ability to build technology that manipulates gravity (trivial interpretations aside). And we also don't know how our actions actually affect the dynamic field that is gravity. Cause the stress-energy tensor says it is dynamic. Or perhaps I'm j…

What exactly are you saying? That once we really figure out gravity, faster-than-light travel will become possible? I've been saying that for years, and I'm no physicist. It's fairly obvious that gravity is not well understood by our physics. All we really know is that it correlates to the presence of mass: lots of mass (like a planet) equals a noticeable amount of gravity. Unlike electromagnetism, where we have the ability to actually create it and manipulate it at will, we have no such ability with gravity (aside from just moving mass around, which has little effect since gravitational force is so weak). So yeah, I've thought for a long time that understanding gravity is the key to warp drive, just because it's such an obvious blind spot. But I'm not sure how this is helpful; merely noticing that our understanding of gravity is poor doesn't actually help us understand it any better.

What we need is to discover a physical effect whereby we can significantly manipulate gravity at will. Figure that out and you'll change everything.

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

#416

Post by aetherson »

gozur88 wrote: post #347
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…

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.

Well, Mercury is in a tidally locked orbit of sorts. Its rotation is resonant with its orbit -- it experiences two days every three years, and this isn't a coincidence, it's a relatively stable outcome of its tidal forces with the sun.

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

#419

Post by pbhatia »

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)

Is that just for the rockets? We would definitely need much more than that considering we would also need to carry at least a city's worth of infrastructure, supplies, settlers, etc.
Post reply on HN