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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

#421

Post by Arizhel »

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…

You sound a little unhinged to be honest. If you're really worried that climate change on Earth is going to cause big problems for humans (which is not an unreasonable concern; climate change threatens to cause significant sea level rise which will cause big problems for people living in sea-level coastal cities), building self-sufficient colonies offworld is a rather extreme answer to that. A simpler answer is to simply move inland, and make sure your structures can handle extreme weather. That's a lot easier than trying to build an offworld colony.

The real reason to build an offworld colony is because you're worried about a big asteroid strike. But here again, it's a lot easier to just build observation systems to spot these threats, and weapons systems to handle these threats, than to build an offworld colony that's truly self-sufficient.

Finally, offworld colonies have gigantic problems with them: 1) people don't handle radiation well, and no place in the Solar System protects us from radiation the way the Earth does, so we'd probably have to burrow underground to mitigate it, and 2) we really don't know how well the human body can handle low-gravity conditions, but we do know that the human body does not handle zero-g well and that it causes massive health problems. There's no place in the Solar System with close to Earth-normal gravity, except for Venus which is a hellhole hot enough to melt lead (on the surface). Mars is only 1/3g, and the Moon is only 1/6g, and pretty much everything else is even less except the gas giants which obviously aren't livable.

Now what climate change and offworld colonies (in this system at least) have to do with our lack of understanding of gravity, I have no idea.

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

#422

Post by MrZongle2 »

yohann305 wrote: post #417

it's worth mentioning that the light we receiving took 39 years to arrive to the telescope. So anything we see happened 39 years ago. I thought it'd be nice to know...

No, it's 39 light-years away.

Meaning that anything there that we can observe happened 39 years ago. Not 39 billion or billion.

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

#423

Post by theossuary »

pbhatia wrote: post #419
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.

I'm pretty sure he meant a probe. Not a good idea to send a bunch of people to a planet we don't know is habitable (and probably isn't).

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

#424

Post by blueprint »

Arizhel wrote: post #415
blueprint wrote: post #374

Earlier quoted context omitted.

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…

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.

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

#425

Post by Arizhel »

drzaiusapelord wrote: post #291
blueprint wrote: post #72

Earlier quoted context omitted.

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. :\

The launch cost of launching the mass of the pyramids of gaza into orbit would bankrupt the richest economies. No your hypothetical engine won't be 100% efficient. This is completely unfeasible. Low mass spacecraft are our only real options. A nano-sized solar sail craft powered by the sun or lasers from Earth can hit up to 20% lightspeed theoretically and its launch costs would be affordable, if not relatively cheap…

>The launch cost of launching the mass of the pyramids of gaza into orbit would bankrupt the richest economies. No your hypothetical engine won't be 100% efficient. This is completely unfeasible.

Not necessarily. You don't need to launch the mass of the pyramids from Earth, you just need to find a source of fuel somewhere else in the Solar System that's in a shallower gravity well, like on the Moon. This is why a lot of people want to work on mining asteroids, and building mining/refining/manufacturing infrastructure offworld.

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

#426

Post by noobermin »

CWuestefeld wrote: post #265
noobermin wrote: post #121

Earlier quoted context omitted.

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.

One of the presenters is an old friend from college. Folks were offering him money to mention "Zod, our Galactic Overlord" on the air. I guess that didn't happen?

No unfortunately, I don't think they did. That would have been hilarious.

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

#427

Post by ccozan »

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?

So it possible to see Avatar like suspended rocks ? Somewhat orbiting some lagrangian point, which is very close to surface.

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

#428

Post by kristopolous »

tim333 wrote: post #142
JumpCrisscross wrote: post #86

Earlier quoted context omitted.

> about...2,000 Saturn V rockets Or about 670 BFRs [1]. It would take 6 cycles of tripling size and/or performance to get a single system with enough thrust to meet your 7/42 year schedule. The Saturn V first flew in 1967 [1]; SpaceX plans to launch its Interplanetary Transport System (ITS) in 2022 or 2024 [2]. That's an expected 60 years to triple performance. [1] http://waitbutwhy.com/2016/09/spacexs-big-fking-rock…

Though that kind of performance is probably not going to come about from improvements to chemical rockets but moving to fusion. There are some promising developments on fusion reactors (see Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte https://www.youtube.com/watch?v=KkpqA8yG9T4 ) Guess something like that with the 100 million C gas doing the propulsion maybe?

There may have to be some clever system where you don't take a lot of fuel with you.

Imagine a type of particle accumulator and aggregator - call it cosmic flypaper. If you're going say 100 km/s, things seemingly insignificant and rare you may be able to collect a lot of pretty quickly.

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

#429

Post by Arizhel »

sand500 wrote: post #192
delecti wrote: post #157

Earlier quoted context omitted.

Just going that fast isn't really risky at all (assuming you don't hit anything, which isn't actually a safe assumption). The tough part is making something capable of a constant 1g of acceleration for a 7 year trip. Most of the craft we make only accelerate for the first small percent of a trip. We can do accelerations that high, but not for very long, and we can't even manage acceleration for such a long duration e…

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.

>Just running into cosmic dust at the speed of light would not be fun.

That's why you need a navigational deflector dish. http://vignette1.wikia.nocookie.net/memoryalpha/images/b/b4/...

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

#430

Post by rlanday »

hughes wrote: post #356
rlanday wrote: post #349

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 memor…

Are you saying that they don't orbit their star because some of them gravitationally influence each other? Or are you saying that nothing outside of our solar system can be a planet? Either way, NASA should schedule another press release about taking celestial pedantry to a new level.

My understanding is that according to the IAU definition, a "planet" must orbit the sun and not any other star. Kind of reminds me of when people thought the solar system was the center of the universe.
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