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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

#431

Post by Balgair »

blueprint wrote: post #338
Balgair wrote: post #332

Earlier quoted context omitted.

The engineering issues are really tough, though surmountable. Currently, we just can't engineer the parts that will last that long in hard vacuum. Mostly because we can't test in that environment easily. Also, what do you do when all the light bulbs have burned out or gone haywire, what does that fault-tree look like for the billion and one parts on the craft? For a short journey of ~7 years, it's not a very big deal…

Yeah I'm to be honest just trying to awaken people to the priority being that we need to establish a self-sufficient colony somewhere other than Earth.

Well, HN is not the most optimal place to do that. There are not many of us on here and we all already know these things. 1600 Pennsylvania Pl. is a better bang for your buck.

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

#432

Post by [deleted] »

blueprint wrote: post #330
matwood wrote: post #295

Earlier quoted context omitted.

NASA is not standing still. Europa just went to the next stage for exploration. http://www.jpl.nasa.gov/news/news.php?feature=6755 It just takes a lot of time to plan and build ships for space travel.

You're completely missing my point. We've known about climate change for a long time. Since the 60s/70s, no? But nobody has been able to realize what it really is, because scientists do not understand gravity yet. I've been begging people to confirm this for themselves instead of believing what others say about it. If people really knew what global warming was they would have started working on ships decades ago. My…

[deleted]

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

#433

Post by UhUhUhUh »

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…

My thoughts exactly. The coolest skyscapes ever! On edit: This also reminds me of U. LeGuin's system in the dispossessed.

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

#434

Post by maverick_iceman »

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…

I'm wondering since these planets are so close to the parent star and to each other would it induce any gravitational instabilities?

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

#435

Post by stouset »

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)

At 0.125g/cm^3 of density, this amounts to a cube of liquid helium about 350 meters per side (43.5 million cubic meters).

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

#436

Post by joshuas »

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 speed doesn't change but the wavelength does. That's why we see light from other galaxies redshifted.

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

#438

Post by lutorm »

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…

It's not like there aren't people working on figuring out how gravity works: https://en.wikipedia.org/wiki/Quantum_gravity

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

#439

Post by Arizhel »

blueprint wrote: post #424
Arizhel wrote: post #415

Earlier quoted context omitted.

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…

FTL etc is a conversation for the future, like a few related topics; but no, the important thing right now I'm saying is that global warming is the first step of a process that we believe has got to be mediated by gravity, and that academia in general doesn't realize what's going on. This needs to be investigated in depth, and this is probably not the venue. You're welcome to contact me.

What the heck are you talking about? Global warming is simple and easily explained by the available evidence: too much carbon in the atmosphere increases the greenhouse effect. All the arguing is how much is "too much" and exactly how much of an effect it'll have. The gravitation of the planet hasn't changed significantly in eons; the atmosphere has because of all the pollution we dump into it.

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

#440

Post by maverick_iceman »

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. :\

Politics, specifically the PTBT[1]. Otherwise Project Orion[2] would be a reality now.

[1] https://en.wikipedia.org/wiki/Partial_Nuclear_Test_Ban_Treat...

[2] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

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