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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

#41

Post by h4nkoslo »

Uh oh.

The "great filter" hypothesis is essentially that the rarity of intelligent life has to be explained by some parameter of the Drake equation, and that whatever the "small" parameter is is either in our past or in our future.

If the "great filter" is the rarity of habitable worlds, then clearly we don't need to fear it, since we already found one. But if habitable worlds aren't rare, then it's more likely it lies in our future (e.g. global thermonuclear war, plague, difficulty of space travel, etc).

Thus things like discovery of exoplanets, bacteria on mars, etc should make us rather concerned.

https://en.m.wikipedia.org/wiki/Great_Filter

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

#42

Post by mtgx »

eb0la wrote: post #3

At Voyager-I speed (17km/s) we need just 688k years to get there. Not bad considering the humble satelite doesn't accelerate anymore.

I doubt we'll attempt serious inter-stellar travel before we figure out antimatter or black hole-powered engines. So we may have to wait a century or two.

This century we should be more worried about making fusion-powered intra-solar system travel a common thing, and about establishing large colonies on Mars and several moons.

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

#44

Post by DanBC »

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?

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

#45

Post by jobu »

The article mentions the star being an ultra-cool dwarf star, but doesn't give an explanation of what that means. Here's some info from Wikipedia that I found useful:

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. In comparison, the Sun is about 4.6 billion years old and has a temperature of 5778 K.

Due to its mass, the star has the ability to live for up to 4–5 trillion years ...

https://en.wikipedia.org/wiki/TRAPPIST-1

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

#46

Post by ionwake »

vkou wrote: post #21
ionwake wrote: post #5

Earlier quoted context omitted.

It's a Trap ;) On a serious note, if we can travel close to the speed of light , say 95%, using for example, nuclear rockets, how long would it take to arrive ? ( from the travellers perspective )

At a constant 1g of acceleration, you could travel there, from the traveler's point of view, in ~2-3 years. (And in ~40 years from a stationary observer's point of view.) Mind you, a constant 1g acceleration (Or accelerating any human-carrying spaceship to relativistic speeds, really,) is about as plausible as a spaceship driven by pixie dust and unicorn farts.

Not according to public research on theoretical designs that have been about for decades . Unless you consider them unicorn farts! I'm only a coder though so I have no knowledge of this domain tho. I think the problem is simply it's too expensive to build space ships that probably won't work at all :( wasnt NASAs budget slashed ?

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

#47

Post by kcorbitt »

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.

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

#49

Post by autokad »

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)

2000 saturn v rockets sounds possible

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

#50

Post by Sharlin »

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?

They are still in separate orbits so the straight line between any two varies greatly in length... not to mention intersecting the star regularly.
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