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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

#211

Post by logfromblammo »

ionwake wrote: post #165
gus_massa wrote: post #94

Earlier quoted context omitted.

> Not according to public research on theoretical designs that have been about for decades. Which ones? Do you have a link? The only one I remember is https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... but it's more a general idea that a detailed blueprint that only need some money to get built.

Thats the one I read. It sounds awesome. Srsly give me 5% of the GDP of the US and I'll put a monkey on Trappist within 5 years. Monkey time. *Im not being serious, I have no idea how much it would cost or if it would even work.

Give me 0.1%, and I'll put a vanOverbruggen "Suzanne" model into a photo-realistic virtual reality imitation of one of the Trappist planets, and I'll throw in reduced head-motion lag in the viewing headgear at no additional charge.

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

#213

Post by ryandrake »

delecti wrote: post #157
wallace_f wrote: post #128

Earlier quoted context omitted.

Is it plausible for anything we'd build to travel .998c and survive the journey?

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…

Also, and I'm not an astrophysicist, but I believe going fast _relative to Earth_ doesn't make it any more or less likely that you're going to hit anything. Moving at .998c relative to Earth and hitting something that is stationary relative to Earth is the same thing as not moving and being hit by something going .998c relative to you.

EDIT: Right, as chris_va pointed out, we're all traveling at .998c relative to something out there.

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

#214

Post by CoolGuySteve »

dexwiz wrote: post #62
jdormit wrote: post #39

Earlier quoted context omitted.

We don't have any spacecraft that can go that fast, do we?

No, but we probably could with enough fuel. The bigger issue is space dust. Hitting it at relativistic speeds would be like flying into a cosmic shotgun for the entire journey.

According to this paper, you can travel around 0.5 c before the radiation caused by colliding with interstellar hydrogen kills you: http://www.scirp.org/journal/PaperInformation.aspx?paperID=2...

"Going slow to avoid severe H irradiation sets an upper speed limit of v ~ 0.5 c. This velocity only gives a time dilation factor of about 15%, which would not substantially assist galaxy-scale voyages. Diffuse interstellar H atoms are the ultimate cosmic space mines and represent a formidable obstacle to interstellar travel."

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

#215

Post by logicallee »

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)

If we had a near-perfect hydrogen -> helium fusion engine, why would we want to stop at 2,000 saturn V rockets of mass? Hydrogen is cheap AF.

Also why would we only want to stop at helium, why not fuse any further?

Also why would you want to stop at 1g acceleration - why not 1.5g or 2g, say? Surely living in 2g environment is okay for that period?

However presumably there is no good reason for us to go there. Just because there are planets doesn't make it worth the trip.

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

#216

Post by phkahler »

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?

If you make the fuel on Mars it will take less effort to get it into orbit. It's also a bit further up the suns gravity well.

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

#217

Post by blueprint »

semaphoreP wrote: post #203
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. :\

A Russian billionaire is trying: https://breakthroughinitiatives.org/Initiative/3

I'm talking about establishing a self-sufficient colony somewhere other than Earth. We have a major crisis on our hands. And few are even willing to consider let alone research and confirm that we're talking about an extinction event much sooner than we thought, maybe on the order of just a couple years out. Problem is, we don't know. Bigger problem is, we're not doing anything about it.

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

#218

Post by dragonwriter »

wallace_f wrote: post #128
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.

Is it plausible for anything we'd build to travel .998c and survive the journey?

> Is it plausible for anything we'd build to travel .998c and survive the journey?

The first half is actually a bigger problem than the second half.

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

#220

Post by blueprint »

raspasov wrote: post #138
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. :\

It sounds like you have a startup idea on your hands : )

You've no idea. But for the first step, I need to find one or two very truthful physics grad students / electrical engineers who feel some responsibility for Earth or saving themselves. You wouldn't happen to know someone?
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