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First atmosphere found on Earth-like planet in habitable zone of distant star

bbc.com

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Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#251

Post by jihadjihad »

PaulDavisThe1st wrote: post #138
dempedempe wrote: post #90

Earlier quoted context omitted.

Even if FTL is achievable (which I agree, highly unlikely), it's still extraordinarily slow on cosmic scales. The closest star is a little over 4 ly away! And probing the universe outside the Milky Way? Forget about it.

1. if FTL is achievable, then presumably it isn't limited to 1.00000000001 x C 2. I like to think about the size of the universe by always remembering that with the naked eye, on a good night, there's only a single object in the entire night sky that isn't in our galaxy (M3, the Andromeda Galaxy).

I think you mean M31 instead of M3, and assuming northern hemisphere viewing only. I think the Magellanic Clouds are visible in the southern hemisphere.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#252

Post by dTal »

rurban wrote: post #250
dTal wrote: post #87

Earlier quoted context omitted.

Even on that scale, major roads and agricultural grids are clearly visible. The mark of abstract intelligence is unmistakeable.

Well, they would see the I-35 out of Houston, but that would show them no sign of intelligence. Just signs of corruption

Heh, your flip remark leads to an interesting observation: I think the most obvious signature of "abstract intelligence" is suboptimality. An alien would look at an agricultural grid and wonder, what possible natural process would divide something into squares rather than hexagons? Even without knowing what they are or how they form, it's hard to imagine anything that would prefer such a high energy configuration. Such stupidity implies a system oddly bounded in its ability to optimize, which implies a feeble biological brain trying to do something "on purpose" rather than a natural process.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#253

Post by somenameforme »

lossolo wrote: post #196
somenameforme wrote: post #128

Earlier quoted context omitted.

Depends on who you mean as "we". The speed of light isn't a speed limit. If you can create a ship that is capable of 1g acceleration, it doesn't just stop accelerating as it reaches the speed of light relative to some stationary object, like Earth. Instead you start getting relativistic effects and things start getting very weird with time and distance doing some funky stuff. You keep zooming along just fine from you…

> If you can create a ship that is capable of 1g acceleration, it doesn't just stop accelerating as it reaches the speed of light For any object with nonzero rest mass, reaching exactly the speed of light in vacuum would require infinite energy.

This is incorrect. This is what an at-rest observer would perceive happening. What happens on the ship itself is very different.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#254

Post by jimbokun »

creesch wrote: post #144
jimbokun wrote: post #2

48 light years is in our back yard. Close enough that we could probably develop a probe to get there in the next few centuries and check it out. What are the current popular candidates for propulsion systems capable of accelerating to near the speed of light?

Just going to recycle this comment I made in reply to an almost identical comment as yours. I don't think you folks realize how big space actually is. The speed of light is 1079 252 848 km/h, the fastest space craft ever made was the Parker Solar probe (using a sling shot) clocking in at 692 000 km/h. So at that speed it would take, 1559 years to travel one light year. This planet sits at a distance of 48 light years…

I want to know what future technologies could accelerate an object to a significant fraction of the speed of light.

What kinds of scientific breakthroughs would be required? Could those breakthroughs be achieved in the next 2 or 3 centuries?

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#255

Post by jimbokun »

pandoro wrote: post #197
teaearlgraycold wrote: post #184

Earlier quoted context omitted.

If we’re talking about human technology available in a few hundred years, don’t discount far more exotic options. I’ve heard people talk of theoretical terrestrial lasers pushing on tiny probes. With an absolutely gigantic laser and magical material at the back of the probe that won’t instantly vaporize there’s enough energy to get something the size of a smartphone up to a reasonable proportion of the speed of light…

Exactly. Imagine what would be possible after a billion year of technological evolution, heck even just 100'000 years. We already know that space time metric engineering is theoretically possible within our current understanding of physics, we don't have either the technology or access to energy density necessary to do it. And that's only within our limited understanding of how the universe works.

Could you expand on what “space time metric engineering” is?

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#256

Post by jimbokun »

ianburrell wrote: post #133
somenameforme wrote: post #128

Earlier quoted context omitted.

Depends on who you mean as "we". The speed of light isn't a speed limit. If you can create a ship that is capable of 1g acceleration, it doesn't just stop accelerating as it reaches the speed of light relative to some stationary object, like Earth. Instead you start getting relativistic effects and things start getting very weird with time and distance doing some funky stuff. You keep zooming along just fine from you…

Relativistic starships are impossible because they require impossible amounts of fuel. "If you can create a ship that is capable of 1g acceleration" is doing a lot of heavy lifting. The rocket equation means you need to take along exponentially increasing amounts of fuel Even antimatter rockets top out at 50% of light speed. Laser boost like with Dyson Swarm could get similar speeds because time dilation slows down t…

50% of light speed would be fucking awesome.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#257

Post by jimbokun »

recursivecaveat wrote: post #163
fellowmartian wrote: post #65

Earlier quoted context omitted.

It’s highly unlikely we’re ever getting FTL. We should become comfortable with that and let go our fantasies. Let theoretical physicists chug away at this, we should get underway with projects that are possible with known science.

We are still so slow and have had space travel for so little time, we are almost certainly on the "wait" side of the wait equation: https://en.wikipedia.org/wiki/The_Wait_Equation

First time I’ve seen that equation.

I love it.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#258

Post by jjk166 »

kazinator wrote: post #242
mr_toad wrote: post #231

Earlier quoted context omitted.

The host star is described as very inactive, which probably accounts for the retention of atmosphere.

A really powerful magnetic field could help, also. Without our field, we would be in trouble, too.

This is false. Earth's magnetic field does not significantly impact atmospheric loss. For comparison, Venus is closer to the sun and has no magnetic field, but has a substantially thicker atmosphere than earth.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#259

Post by jjk166 »

tsoukase wrote: post #233

I think we should focus at the solution of Fermi paradox, especially the short time window factor. Life on earth evolved for billions of years, while one of it's creatures is capable to receive/send messages to space for only 50. That leads to a factor of billions/50 reduction at the calculated probability of alien life discovery. Multiply that with another billions/xxx at the receiver side, if they are similarly abl…

Considering we started our search for extra terrestrial intelligence 67 years ago, and we likely didn't go extinct in 2009, 50 years seems a rather pessimistic estimate.

Re: First atmosphere found on Earth-like planet in habitable zone of distant star

#260

Post by tonmoy »

jjk166 wrote: post #258
kazinator wrote: post #242

Earlier quoted context omitted.

A really powerful magnetic field could help, also. Without our field, we would be in trouble, too.

This is false. Earth's magnetic field does not significantly impact atmospheric loss. For comparison, Venus is closer to the sun and has no magnetic field, but has a substantially thicker atmosphere than earth.

I’m not 100% sure I follow what you mean, but here is a link from NASA saying our magnetosphere protects the atmosphere from erosion https://science.nasa.gov/science-research/earth-science/eart...
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