Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Two potentially life-friendly planets found orbiting a nearby star

nationalgeographic.com

Post reply on HN
Print view View original

151–160 of 391 posts

Re: Two potentially life-friendly planets found orbiting a nearby star

#151

Post by petercooper »

tictoc wrote: post #50
lmm wrote: post #30

Earlier quoted context omitted.

> I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-) If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.

Imagine being the child born on the ship on a crash course to this new planet.

Imagine being the child born on the ship on a crash course to this new planet.

Here's one for you. What if WE are the children currently on a 'ship' (Earth) being sent somewhere..? ;-)

Re: Two potentially life-friendly planets found orbiting a nearby star

#152

Post by jniedrauer »

gameswithgo wrote: post #134
sametmax wrote: post #96

Earlier quoted context omitted.

I smiled as well but with a slowly but steadily accelerating ship we can reach half the light speed and get there in 50 years. It put things in the realm of "possible" which is amazing.

now do some napkin math on the reaction mass and energy you need to slowly accelerate that much for that long

And the energy transferred by an impact with a piece of dust at luminal speeds

Re: Two potentially life-friendly planets found orbiting a nearby star

#153

Post by onemoresoop »

corodra wrote: post #115
onemoresoop wrote: post #108

Earlier quoted context omitted.

Of course we’re far from it, if ever possible. I was just being playful on the whole premise of “colonizing” another earthlike planet

Oh, I'm not bashing you at all. You're absolutely correct. You bring up extremely important things to realize when discussing space travel. Especially long term missions. Political will being the reason why these missions haven't happened, as someone else mentioned, is total crap. It's just an easy excuse to not think of ACTUAL consequences and live in a scifi fantasy.

Yes I agree, we seem to be working on the wrong problems or get the priorities wrong. We keep on inventing newer technologies which come with newer problems while the ship is slowly but surely sinking. Sometimes I wonder what would it take for all of us to join a concerted effort to concentrate on the real problems we have. Technologies seem to veer into an escapist route, some way for us to run away from the problems we do have: virtual reality, leisure space travel, AGI, synthetic life, immortality.. I hope we'll eventually wake up in the last hour, at least to acknowledge where we've gone wrong.

Re: Two potentially life-friendly planets found orbiting a nearby star

#154

Post by entropea »

inetknght wrote: post #150
XorNot wrote: post #107

The note that it's an old star makes me worry though. If they're older then us, and habitable, were they inhabited? Our current era is a few hundred years of real, directed technological development. A few thousands years either side of that and who knows what we'd be looking at, but you imagine that - hopefully - the general progression of technology is forward. So if they were inhabited, what happened to them? Are…

> Are they exactly at our level of development? If so, then at just 12ly away, we could converse with them within (many of) our lifetimes.

What are the chances that would've already happened given how long we've been sending life made RF off the planet? A 24 year exchange isn't awful.

Re: Two potentially life-friendly planets found orbiting a nearby star

#156

Post by interfixus »

gameswithgo wrote: post #134
sametmax wrote: post #96

Earlier quoted context omitted.

I smiled as well but with a slowly but steadily accelerating ship we can reach half the light speed and get there in 50 years. It put things in the realm of "possible" which is amazing.

now do some napkin math on the reaction mass and energy you need to slowly accelerate that much for that long

Now do some napkin math on the amount of gears and levers you need to reach such calculating power, mr. Babbage.

Re: Two potentially life-friendly planets found orbiting a nearby star

#157

Post by isostatic »

cygx wrote: post #105
gambiting wrote: post #85

Earlier quoted context omitted.

Well, for the journey itself the problem has a simple solution - more shielding. Then of course we have to answer the question of how can we get ships into orbit when they are full of shielding, but that's not insurmountable. The bigger issue is actually living on mars - as romantic as that idea is, human habitation on the surface is really dumb, the radiation level is not insignificant, so anything long term would e…

Then of course we have to answer the question of how can we get ships into orbit when they are full of shielding, but that's not insurmountable. If regular travel becomes a reality, you wouldn't shield the launch vehicle, but the cycler[1]. [1] https://en.wikipedia.org/wiki/Mars_cycler

The benefit of using a cycler rather than a ship that travels orbit-to-orbit is that there is no need to accelerate/decelerate the mass of the ship, just the perishables (people and provisions for the voyage)

You would accelerate a small vessel (like a crew dragon or orion), intercept and dock with the much larger cycler, then enter the ship for your x-month trip.

When you near mars, you get back into your dragon, and burn away from the cycler, entering into martian approach.

7 people in a Crew Dragon for 18-24 months would not be pleasant. 7 people in a flying space hotel would be far nicer.

You could presumably look at using a small asteroid to provide the bulk of the "cycler", offering plenty of shielding for the trip, you'd only have to get it into position once - far less fuel requirement.

My understanding though is Musk is planning on using BFR to go surface-to-surface, with maybe a refuel in earth orbit. I believe this is because of the amount of material that needs transporting to Mars for the first 20 years or so, and that mass can be used as useful shielding. Even if Mars becomes self sustaining and doesn't require a large amount of cargo:people ratio, I believe Musk is aiming for a much shorter transit time than 2 years.

Re: Two potentially life-friendly planets found orbiting a nearby star

#158

Post by iamgopal »

mabbo wrote: post #89

Being that close also offers us a better ability to examine it. The nearer the star, the more arc-seconds (or tiny fractions thereof) the star will appear in telescopes. 12ly is ridiculously close! It also tells us something interesting. If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitab…

One more benefit is, we are looking at very recent past instead of hundred and thousands year past in comparative other planted.

Re: Two potentially life-friendly planets found orbiting a nearby star

#159

Post by marcosdumay »

jerf wrote: post #17
sushibowl wrote: post #13

Earlier quoted context omitted.

This was indeed the prevailing wisdom for some time. However, more recent research is somewhat more optimistic. Even an atmosphere 10% as dense as that of earth can circulate heat to the dark side efficiently enough, given the right composition. The night side temperature could be within the parameters required to sustain some form of life. Furthermore, tidal locking is dependent on oceans and atmosphere, and can tak…

"However, more recent research is somewhat more optimistic." I am deeply skeptical of that "recent research", which AFAIK is "computer models, where we have zero capability to verify the computer models against even a single data point". The incentives to keep kicking the computer model until it provides something publishable, with no countervailing force provided by real data to be explained by the model, are just t…

Every new simulation is publishable. And every simulation that is more detailed than what came before will receive some attention after being published.

If physics has some bias they polish their models towards, it's on the direction of repeating the findings of the previous ones, not of changing them.

Re: Two potentially life-friendly planets found orbiting a nearby star

#160

Post by stcredzero »

XorNot wrote: post #107

The note that it's an old star makes me worry though. If they're older then us, and habitable, were they inhabited? Our current era is a few hundred years of real, directed technological development. A few thousands years either side of that and who knows what we'd be looking at, but you imagine that - hopefully - the general progression of technology is forward. So if they were inhabited, what happened to them? Are…

The note that it's an old star makes me worry though. If they're older than us, and habitable, were they inhabited?

Many dwarf stars have more solar flares than our sun, while their planets are closer. Teegarden's star is supposed to be very calm right now. I have no idea if that is likely to be true over most of the past 8 billion years. The amount of water they gather may be smaller, and their closer planets may not be able to retain water as well.

So if they were inhabited, what happened to them?

Let's say the origin of life is a million to one filter, and the successful development of sentience is another million to one filter. Those are actually pretty high odds for those two events, and the combination of those two togehter is enough to make it likely we're alone in the Milky Way.

One thing's for sure - if there's really 2 habitable planets, with liquid water, then we've got a hell of a target to point James Webb at when it launches - an infrared spectrum star should mean any plant life is well optimized to towards the redder end of the spectrum - we should see some type of chlorophyll.

Since most of the star's energy is emitted in the infrared, which is a more diffuse form of energy, does this limit the potential of photosynthetic organisms to gain a disruptive evolutionary advantage? (Maybe not. It's still free energy from the sky.)

Post reply on HN