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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

#121

Post by noobermin »

chrisabrams wrote: post #36
bcaulfield wrote: post #10

Earlier quoted context omitted.

So, basically, this is cooler than just about any world that's been depicted in sci-fi.

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.

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

#122

Post by hughes »

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…

> trillions of years

This is off by several orders of magnitude. Like estimating the age of your neighbor to be somewhere around 400,000 years old.

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

#123

Post by bsmith89 »

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)

For anyone (like me) who wants to adjust the parameters while not having to deal with calculus, this[1] "Space travel calculator" works great.

[1]: http://nathangeffen.webfactional.com/spacetravel/spacetravel...

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

#124

Post by antognini »

rm_-rf_slash wrote: post #30
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?

Actually they are fewer. A dim star has less high energy radiation and a lower probability of harmful solar flares.

That's backwards. Red dwarfs have extremely powerful flares relative to their luminosity. So much so that it's unlikely that life would survive on the surface of an orbiting planet. (Though life would probably survive underwater.)

https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_syst...

https://en.wikipedia.org/wiki/Flare_star

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

#125

Post by semaphoreP »

twoodfin wrote: post #105
cletusw wrote: post #7

Apparently finds are close enough to us that we should be able "to follow up, to see, for example with the James Webb Space Telescope that we're going to launch [next] year, the atmospheres and also to look at bio-signatures, if there are any" !

Optically? That's nuts! Anyone know how this would work? Can we really expect Webb to measure light diffraction/refraction through a few miles of atmosphere on a planet 40 ly away?

It'll be in the near-infrared, but the light won't be separated from the star. How they observe the atmosphere is that when the exoplanets transit, they block out different amounts of light at different wavelengths. From that, one can deduce an atmospheric spectrum.

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

#126

Post by xigency »

aaronblohowiak wrote: post #112
jdormit wrote: post #39

Earlier quoted context omitted.

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

I think we do if you look at it in terms of acceleration. As I understand it, In space there is almost 0 friction so "fast" is more about acceleration than "top speed". In this view, 1g isn't that fast.

About as "fast" as a helicopter at a stable altitude, or to fit with the no-atmosphere bit, a stationary jetpack or lunar lander (on Earth).

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

#127

Post by John23832 »

actsasbuffoon wrote: post #114
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)

It would take 37 days at warp 6 (assuming we're using the new warp factors established in The Next Generation). I have no idea how much dilithium crystal would be required though.

Why can't I up vote more?

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

#128

Post by wallace_f »

kcorbitt wrote: post #47
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)

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?

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

#129

Post by marssaxman »

VikingCoder wrote: post #97
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 many Saturn V rockets have we launched in total?

Thirteen: the last was Skylab.
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