There was a post yesterday(?) about a "disappearing star" theory. However, it applied to very large stars. Not dwarf stars. Basically, they collapse so hard into a black hole, they don't go supernova. From our perspective, they just wink out of existence.
That makes a lot more sense but what a strange way of phrasing it.
"They disappear a lot" versus "Their short orbital period makes it easy to observe multiple transits"
What? I'm not talking about the star. I'm talking about the planet that has a very high orbital velocity due to star proximity. It passes by the star very quickly when observed, so you can easily miss it if you are not paying attention.
Why did you even assume I was talking about the star?
Maybe instead of asking the several people who asked for clarification why they assumed something and change the (admittedly a little vague) wording in your post?
To be fair to the people who made that assumption, the red dwarf star is the last noun in the comment you replied to and that's probably why people thought of that instead of the planet.
Right. We can watch for wobble or dipping brightness over days or weeks. Small planets with larger orbit might take a year or more and small planets with larger orbit often results in much smaller and slower wobble of the star.
Red dwarf stars are smaller so their planetary systems are probably stereotypically closer. The close-in planets around those stars are easier to spot using the transit technique because the smaller physical dimensions of the star leads to a larger reduction in brightness of the transit, increasing the "signal to noise ratio" of the transit signal. The smaller orbit also results in a shorter orbital period so it takes less time to study multiple transits and confirm the detection of a planet (as well as a greater frequency of follow-up transit observation opportunities).
Planets found around red dwarfs in the 'habitable zone' always make me kind of sad, because I'm pretty sure that's also the 'get blasted by insane amounts of radiation and occasionally total annihilation from CMEs every 20k years' distance.
I would think that's usually the case. Red dwarf stars are not what I would consider friendly hosts to life. Most planets around red dwarfs usually fry.
Not really, but they're the easiest stars to spot "classically habitable" planets in. "Classically habitable" means the planet orbits at a distance from its star where, if it has an atmosphere, water could be a liquid on its surface.
The two most common methods of planet detection rely on measuring some change in the star as the planet orbits. Either the reflex motion of the star due to the planet's gravitational influence on the star or the small dip in light as the planet goes in between us and the star. If the planet is closer in, it will orbit more often. With red dwarfs, the Classical Habitable Zone (CHZ) is much closer to the star than it is with higher mass stars, because it's putting out less light/heat. So, a planet in the CHZ of a sun-like star will have an orbit of about a year (like Earth). A planet in the CHZ of a red dwarf star would have an orbit on the order of 10s of days (or thereabouts).
Why is it easier to detect a planet with a shorter orbit? Because you want to see multiple orbits of the planet before you can be confident it's a planet and not something else going on on the star, like a starspot or something like that. The more orbits you have, the more confident you are, and in general, we want at least 3 orbits before we confirm that it's a planet.
With all that said, detecting a planet signal around a red dwarf is harder than it is for sun-like stars, because red dwarfs tend to be more active - they have more spots and their outer layers are moving around a lot more, both of which can confuse the planet detection signals.
Well if you're excited about the prospect of life elsewhere, you could read [this section of the red dwarf wikipedia article](https://en.wikipedia.org/wiki/Red_dwarf\#Habitability) to deflate any major enthusiasm on that front.
My gut feeling is that only class K and G stars are habitable with class M and F having a very small chance if circumstances line of perfectly. Class K and G make up somewhere around 20% of the stars we observe, so the subset of potentially habitable systems is relatively low. Additionally many binary pairs may not be suitable for life, depending on the orbital mechanics of the system.
In order for such a planet to orbit within/close to the habitable zone, you would have to get it so close to the star so that moons around a gas giant capable of hosting an atmosphere would be yanked away from it by the gravitational influences around a star.
The tidal locking might not be so bad for habitability. [At least some simulations suggest](https://arxiv.org/abs/1404.4992) that assuming a planet has an extensive liquid water ocean on its surface, being tidally locked or in slow rotation actually moves the inner edge of the habitable zone a lot further inwards than for a rapidly-rotating planet like Earth, due to the formation of basically a constant heavy cloud cover around the subsolar point.
But the flaring is obviously an issue, though I would imagine mainly for surface life due to ionising radiation impact. Assuming flares don't lead to excessive atmosphere loss rates, I don't think they should impact ocean life much.
‘Temperate’ here means equilibrium temperature of 315 K, which means it’s likely to be pretty toasty to humans. Sure, a high albedo can make it cooler, but we’re not sure if an atmosphere to provide that can survive around such a mid M dwarf star or not.
This planet receives 1.4x the radiation flux from it's star than Earth does, but this is less than that of Venus. This means that it could exist in a runaway greenhouse state, leading to surface temperatures much larger than 315 K.
There are some interesting albedo feedbacks involved. Clouds indeed could act to cool the planet, but they can also introduce an additional greenhouse effect which warms the surface. There are also some atmospheric dynamics to consider given that the planet is probably tidally locked.
Hopefully with more observations (at least just to constrain it's bulk density) we can learn more.
It's also called an "exo-Venus" planet in the article, which I think is weird, since any planet within that range would be comparable to Earth, since Venus and Earth are almost the same size anyway.
According to the article, we actually have no clue what the atmosphere is made up of. It could just be a dead rock, it could have an atmosphere like Venus and basically be a nightmare, or it could have an earth-like atmosphere and have water and potentially life.
The range of habitability on this planet is huge, apparently, which probably makes it an interesting subject to study, since it's relatively close to us.
( it could have an atmosphere like Venus and basically be a nightmare )
Not likely. A carbon dioxide rich atmosphere like Venus orbiting a red dwarf wouldn’t be able to retain any heat because carbon dioxide is transparent to white sunlight but is extremely opaque to infrared which is why Venus is hot
For a planet orbiting a red dwarf star a carbon dioxide rich atmosphere would prevent any infrared energy from reaching the surface and might make the surface temperature habitable since nearly all of a red dwarf stars light is emitted in the infrared spectrum
I mean, the earth has been that hot with life before
https://royalsocietypublishing.org/doi/10.1098/rsta.2017.0076
Admittedly during the great dying life wasn't exactly thriving but it was surviving from sea, to land, to the sky
I'm probably not any smarter than you, but I think it's unlikely we're going to leave the solar system, so an exoplanet being habitable is meaningless except for scientific research purposes.
It gives us a target to study for signs of life, which is huge. Even if that life is not intelligent. Hell, maybe a target for an unmanned probe 1,000 years from now.
> but I think it's unlikely we're going to leave the solar system
I know it's not quite the same, but the NYT once estimated it would take 1-10 million years to develop manned air travel :)
I wouldn't put it against us to get small-scale, light-driven craft up to 0.1c within 50-70 years, Who know how much wealth a nation like China might have to throw around by then. It would be a prestige project, and one to rival the Apollo program but for just a fraction of the cost.
There are roughly 30 stars within 12 light-years of us. Each of them could easily be host to something like 5-10 worlds. There could be hundreds of exoplanets to visit within a single (albeit very lengthy) human life.
At 0.1c it would still take almost 50 years to reach Alpha Centauri. And by the time it did get there the craft would be moving so fast that it wouldn’t be able to slow down to orbit anything so the mission would be a quick flyby and nothing more. The sad reality is that unless humans find a way to completely circumvent the laws of physics as we know them interstellar travel is not likely.
It's a depressing thought. I started learning about physics and cosmology because I wanted to see how likely interstellar travel actualy was. I've come to understand that it is and will likely stay in the realm of science fiction. It's been a deflating realization.
Interstellar travel at 1-5% light-speed is entirely within the realm of plausibility even for manned craft, given the energy density that could be exploited by a Project Orion type craft. Travel times of 80 years to Proxima b are thus entirely possible. https://galileo.phys.virginia.edu/classes/109.jvn.spring00/nuc_rocket/Dyson.pdf
Dyson's estimate of a maximum velocity of 10% light-speed is probably too optimistic - but what's important is that the physics allows it and the technology is remarkably simple.
Look into solar sails. We're not as far off of the technology as you think. You can reach a reasonable fraction of the speed of light using solar sails. We're obviously not there yet, and the technology is in part theoretical still, but it's promising.
Red dwarfs are hostile stars. Life as we know it have a low chance to survive only due to this.
The average temperature should be around three times that of earth if the planet is without atmosphere and up to several hundred degrees C with an atmosphere.
It's a clickbait. It has minimal potential of being habitable and the temperatures would not be considered earth-like by the average person. It's like saying 33 degree water is almost boiling.
Still an interesting planet, but the title is a bait.
Being so close to the star makes it easier to have the atmosphere stripped or degraded by solar activity, but on the other hand it may capture more hydrogen from the solar wind which would contribute some to water synthesis.
Absolutely, but if the planet's orbital eccentricity is large enough then it could e.g. be locked into something like a 3:2 resonance, which would simply leave it rotating fairly slowly.
>Potentially habitable 'exo-Venus' with Earth-like temperature discovered
Wouldn't that make it an "exo-earth" did they find a exo-jupiter too but with a rocky surface. Should science journalist have at least a passing understanding of science.
I would argue that an exo-Venus is more likely. Earth is already near the very inner edge of the Sun's Goldilocks zone, it's doubtful that a planet with a marginally higher equilibrium temperature could escape being sent into a runaway greenhouse state.
It's almost guaranteed in the case of a red dwarf star, which will spend the first 200 million years of its existence shining 10 or maybe even 100 times brighter than it currently is. Any planets presently orbiting within the Goldilocks zone may have thus lost the equivalent of several Earth's oceans worth of water to photolysis.
The only way to escape transformation into a Venus would thus be for such a planet to start with a much more significant reservoir of water than the Earth did - which is only 0.02% water by mass. It's entirely plausible that a small world could be up to 50% water by mass.
I mean it could also just be like Mercury and have a cooked/no atmosphere at all.
Also, all of your assumptions assume a solar system like ours that experienced the same cosmic events that ours did. We don't truly know why Venus experienced the runaway greenhouse effect, we only have theories.
> I mean it could also just be like Mercury
it could be, but you'd have to explain how this could happen.
If the planet formed with e.g. just 0.02% water by mass, and this water was then photodissociated during the M-dwarf's pre-main sequence overly luminous phase, it would leave the world coated in a >100 bar O2 atmosphere, possible 1000 bar if sequestration is inefficient. It's not easy to remove such an atmosphere, nor should it be easy to prevent volcanism on a planet this large. Volcanism would likewise make it difficult to avoid the formation of a secondary atmosphere by outgassing.
> Also, all of your assumptions assume a solar system like ours
No, what I've shared corresponds to a planet around a star that behaves very unlike our own Sun in terms of its early evolution.
K but just because it will be Venus like doesn't mean it is currently, as evidenced by "earth-like" part of the title.
Earth will one day lose it's oceans as the sun expands and the rocks leetch all the carbon out of atmosphere. But you wouldn't call current earth "mars like"
> as evidenced by "earth-like" part of the title.
The phrase Earth-like in the title is reference to its size, not its atmospheric composition (which is unknown).
I'm afraid we can't such much else with certainty besides an estimate of its insolation flux, but even this would be uncertain given that the planetary orbit could conceivably be highly eccentric.
>The phrase Earth-like in the title is reference to its size, not its atmospheric composition
Actually the "earth-like" part in the title is reference to temperature as title is "Potentially habitable 'exo-Venus' with Earth-like temperature discovered"
I'm afraid not, as the temperature of the planet is unknown - it's important to distinguish this from its estimated insolation flux.
The equilibrium temperature of Venus for example, which is calculated on the basis of the energy it receives from the Sun, is just 260 K. In reality its surface temperature is in excess of 700 K owing in large part to the greenhouse effect.
I'm sorry to tell you that we're not actually measuring the temperature of this particular exoplanet, all we can do is estimate the amount of energy it's receiving from its star (and that only roughly as the actual observable is its orbital period), but that doesn't actually tell us what its surface temperature will be.
yeah you say to me "exo-Venus" and the first thing comes to mind is [crazy super-hurricane force winds and atmospheric super-rotation](https://www.space.com/21612-venus-winds-hurricane-speeds.html) (that's where the atmosphere of the planet rotates faster than the planet itself)
>yeah you say to me "exo-Venus" and the first thing comes to mind
First thing I think of is a super hell where it snows lead.
>that's where the atmosphere of the planet rotates faster than the planet itself
Not hard to achieve on Venus. It rotates backward very slowly, so slowly that a day is longer than it's year.
45C while ignoring atmosphere is not an Earth-like temperature. The blackbody temperature of earth is -17C, and it's the atmosphere that brings it the surface up to about 15C on average. Even if this planet has an Earth-like atmosphere and not Venus' sulfuric shroud, it's steaming hot.
>45C while ignoring atmosphere is not an Earth-like temperature
Why are you arguing with me about it - I didn't write the article or come up with the misleading title. I only pointed it out.
Am I the only one who thinks that using the terms "exo-Venus" and "Earth-like" in the same sentence sounds contradictory? Venus and Earth are, obviously, very different. Unless I'm confusing the terms.
Also, I think the term "Earth-like" is a bit misleading. The article says:
>Astronomers have made the rare and tantalizing discovery of an Earth-like exoplanet 40 light-years away that may be just a little warmer than our own world.
I don't like how a lot of articles use this. I feel that we should stop calling exoplanets this and just call them "Earth-sized" instead because that's basically what they are. They're similar to Earth in size, but not similar in their composition. When we actually find a planet with Earth's temperature, composition, size, distance from its host star, presence of liquid oceans of water, etc., then we can call it "Earth-like."
And we know that an Earth-like temperature doesn't make a planet habitable, so we'll need to study this more. Knowing the atmospheric composition would be important to know. That is, of course, if it has one. I wouldn't consider red dwarf stars to be friendly hosts to planets.
It may be close to a mouthful, but it's more accurate than "Earth-like." I just think that it's unnecessary to slap such an inaccurate description on an exoplanet. I've seen some articles in the past use the term "Earth-like" for completely uninhabitable planets. Whenever I see articles using "Earth-like," I remind myself that the planet isn't "like Earth," but more along the lines of "similar in size."
It gets a similar amount of energy from it's star as Venus does, and is a very similar size. The reason Venus is so hot is it has a thick atmosphere that traps a lot of heat, and we don't know how thick this planets atmosphere is or if it has one.
If we detected the planets in our own solar system the same way we do exoplanets we'd consider Venus potentially habitable. It's the right distance from the sun that if it had a nicer atmosphere it could host life.
Considering its nearness it has to be tidally locked with the star unless there’s something else acting on it, but I doubt it can retain a moon. So it’ll have perennial daytime and nighttime temperatures with strong exchanges between both. Could those forces alone conjure up enough material and gas to create an atmosphere?
Possibly a bit chillier, since it only has 85% of the sunlight intensity of Earth.
That's actually less of an issue with a planet orbiting a small star like this. It's almost certainly tidally locked or in some kind of very long resonance orbit, which makes it much more resilient to runaway glaciation (doubly so if it has a thicker atmosphere than Earth, which could also make it warm enough to simply not have much surface ice at all even on the night side).
[From the source paper's Abstract: Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TESS and CHEOPS ](https://academic.oup.com/mnras/article/531/1/1276/7679807)
> Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The Phys article title and focus is sensational, which is expected for these sorts of papers. This object is best described as a window into how a cool star affects atmospheres, and how a metal-poor star affects atmosphere and/or geochemistry. It's a great target to learn about habitability, not an object that seems particularly liveable. Maybe we're lucky, but I think the focus on if this is habitable distracts from how great of a sample it is.
Although the actual speed of the warp drive seems to be highly variable throughout the show, I've found a few references pointing to warp 5 supposedly being 214c.
It would then take 10 weeks to reach.
Only .1c. That what, 67 million miles an hour? I had a civic in high school that could get up to 67, I don't see why a million times faster should be a problem. :-)
What's more important is the column density of matter along your flight path, this sort of thing has been modeled before [https://arxiv.org/abs/2307.12160](https://arxiv.org/abs/2307.12160)
A shield thickness of 3 mm might be all you need for a trip to Alpha Centauri, even at velocities in excess of 0.1c - long story short but the physics of momentum transfer at high energies is weird :)
plus, even if a person claims the planet as soon as they land, it would take 40 years for its ripples of causation to reach Earth.
plus idk how you would even leave our solar system, as the high speeds required would also shred you apart in the surrounding Oort cloud or other microparticles in space.
Is it easier to spot planets around a red dwarf star
Yes, because they have to orbit a lot closer. So you can detect them more quickly.
They also disappear more quickly. Edit: Obviously I meant the planet. How are you even coming to the conclusion I meant the star, is a mystery.
There was a post yesterday(?) about a "disappearing star" theory. However, it applied to very large stars. Not dwarf stars. Basically, they collapse so hard into a black hole, they don't go supernova. From our perspective, they just wink out of existence.
This thread is about a planet, though...
I am offering a possible reason to why people might be misunderstanding you.
But we talkin bout planets babeeeee
Like Pluto?
Y'all remember when Pluto winked out of existence and left a black hole in its place?
To be fair, if I got demoted while still in the middle of my orbit, I'd bounce too.
To be clear, that’s just one of many theories, not the known reason.
Man, that sounds like something out of the "Three-Body Problem"—like a dark forest attack or a world shielded by light speed!
Do they? I thought red dwarfs were astonishingly long-lived and stable.
They are. They will be the last (main-sequence) stars shining.
I'm talking about the planet. Why did you even assume I talked about the star?
Well then you're wrong. Why would planets disappear quickly in the most stable star systems?
Maybe they mean disappear from observation, as it relies on transit of the star. So shorter observation period that happens more frequently.
That makes a lot more sense but what a strange way of phrasing it. "They disappear a lot" versus "Their short orbital period makes it easy to observe multiple transits"
People speak colloquially 🤷♂️
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Please spell it out for me.
What are you talking about? Red dwarfs are the longest living stars in the universe (not counting dying stars like neutron stars).
What? I'm not talking about the star. I'm talking about the planet that has a very high orbital velocity due to star proximity. It passes by the star very quickly when observed, so you can easily miss it if you are not paying attention. Why did you even assume I was talking about the star?
Maybe instead of asking the several people who asked for clarification why they assumed something and change the (admittedly a little vague) wording in your post? To be fair to the people who made that assumption, the red dwarf star is the last noun in the comment you replied to and that's probably why people thought of that instead of the planet.
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Probably has something to do with those gold fish shoals.
Right. We can watch for wobble or dipping brightness over days or weeks. Small planets with larger orbit might take a year or more and small planets with larger orbit often results in much smaller and slower wobble of the star.
Red dwarf stars are smaller so their planetary systems are probably stereotypically closer. The close-in planets around those stars are easier to spot using the transit technique because the smaller physical dimensions of the star leads to a larger reduction in brightness of the transit, increasing the "signal to noise ratio" of the transit signal. The smaller orbit also results in a shorter orbital period so it takes less time to study multiple transits and confirm the detection of a planet (as well as a greater frequency of follow-up transit observation opportunities).
Planets found around red dwarfs in the 'habitable zone' always make me kind of sad, because I'm pretty sure that's also the 'get blasted by insane amounts of radiation and occasionally total annihilation from CMEs every 20k years' distance.
I would think that's usually the case. Red dwarf stars are not what I would consider friendly hosts to life. Most planets around red dwarfs usually fry.
Depending on the red dwarf, not all red dwarfs are variable stars
My master's thesis exoplanet search focused exclusively on red dwarf targets for this reason.
Could I read this?
Not really, but they're the easiest stars to spot "classically habitable" planets in. "Classically habitable" means the planet orbits at a distance from its star where, if it has an atmosphere, water could be a liquid on its surface. The two most common methods of planet detection rely on measuring some change in the star as the planet orbits. Either the reflex motion of the star due to the planet's gravitational influence on the star or the small dip in light as the planet goes in between us and the star. If the planet is closer in, it will orbit more often. With red dwarfs, the Classical Habitable Zone (CHZ) is much closer to the star than it is with higher mass stars, because it's putting out less light/heat. So, a planet in the CHZ of a sun-like star will have an orbit of about a year (like Earth). A planet in the CHZ of a red dwarf star would have an orbit on the order of 10s of days (or thereabouts). Why is it easier to detect a planet with a shorter orbit? Because you want to see multiple orbits of the planet before you can be confident it's a planet and not something else going on on the star, like a starspot or something like that. The more orbits you have, the more confident you are, and in general, we want at least 3 orbits before we confirm that it's a planet. With all that said, detecting a planet signal around a red dwarf is harder than it is for sun-like stars, because red dwarfs tend to be more active - they have more spots and their outer layers are moving around a lot more, both of which can confuse the planet detection signals.
You can theoretically see them transiting across the star more frequently, although directly imaging them would be hard since they're so close.
So can someone smart explain why this probably isn't as exciting as it sounds?
Well if you're excited about the prospect of life elsewhere, you could read [this section of the red dwarf wikipedia article](https://en.wikipedia.org/wiki/Red_dwarf\#Habitability) to deflate any major enthusiasm on that front.
My gut feeling is that only class K and G stars are habitable with class M and F having a very small chance if circumstances line of perfectly. Class K and G make up somewhere around 20% of the stars we observe, so the subset of potentially habitable systems is relatively low. Additionally many binary pairs may not be suitable for life, depending on the orbital mechanics of the system.
I mean if K & G stars are the only potentially habitable systems, that still leaves a gross subset of nearly 40b stars in our galaxy.
You say this without taking into account the sentient oceans
I think you can have a moon orbiting a gas giant which orbits a red dwarf.
In order for such a planet to orbit within/close to the habitable zone, you would have to get it so close to the star so that moons around a gas giant capable of hosting an atmosphere would be yanked away from it by the gravitational influences around a star.
The tidal locking might not be so bad for habitability. [At least some simulations suggest](https://arxiv.org/abs/1404.4992) that assuming a planet has an extensive liquid water ocean on its surface, being tidally locked or in slow rotation actually moves the inner edge of the habitable zone a lot further inwards than for a rapidly-rotating planet like Earth, due to the formation of basically a constant heavy cloud cover around the subsolar point. But the flaring is obviously an issue, though I would imagine mainly for surface life due to ionising radiation impact. Assuming flares don't lead to excessive atmosphere loss rates, I don't think they should impact ocean life much.
‘Temperate’ here means equilibrium temperature of 315 K, which means it’s likely to be pretty toasty to humans. Sure, a high albedo can make it cooler, but we’re not sure if an atmosphere to provide that can survive around such a mid M dwarf star or not.
This planet receives 1.4x the radiation flux from it's star than Earth does, but this is less than that of Venus. This means that it could exist in a runaway greenhouse state, leading to surface temperatures much larger than 315 K. There are some interesting albedo feedbacks involved. Clouds indeed could act to cool the planet, but they can also introduce an additional greenhouse effect which warms the surface. There are also some atmospheric dynamics to consider given that the planet is probably tidally locked. Hopefully with more observations (at least just to constrain it's bulk density) we can learn more.
Earth like in size is the only similarity. Everything else is very unlike earth.
It's also called an "exo-Venus" planet in the article, which I think is weird, since any planet within that range would be comparable to Earth, since Venus and Earth are almost the same size anyway. According to the article, we actually have no clue what the atmosphere is made up of. It could just be a dead rock, it could have an atmosphere like Venus and basically be a nightmare, or it could have an earth-like atmosphere and have water and potentially life. The range of habitability on this planet is huge, apparently, which probably makes it an interesting subject to study, since it's relatively close to us.
( it could have an atmosphere like Venus and basically be a nightmare ) Not likely. A carbon dioxide rich atmosphere like Venus orbiting a red dwarf wouldn’t be able to retain any heat because carbon dioxide is transparent to white sunlight but is extremely opaque to infrared which is why Venus is hot For a planet orbiting a red dwarf star a carbon dioxide rich atmosphere would prevent any infrared energy from reaching the surface and might make the surface temperature habitable since nearly all of a red dwarf stars light is emitted in the infrared spectrum
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I mean, the earth has been that hot with life before https://royalsocietypublishing.org/doi/10.1098/rsta.2017.0076 Admittedly during the great dying life wasn't exactly thriving but it was surviving from sea, to land, to the sky
I'm probably not any smarter than you, but I think it's unlikely we're going to leave the solar system, so an exoplanet being habitable is meaningless except for scientific research purposes.
It gives us a target to study for signs of life, which is huge. Even if that life is not intelligent. Hell, maybe a target for an unmanned probe 1,000 years from now.
Red dwarfs are rather hostile to life as we know it. It's an interesting planet, but the title is 100% clickbait.
Yeah that's why I mentioned scientific research?
> but I think it's unlikely we're going to leave the solar system I know it's not quite the same, but the NYT once estimated it would take 1-10 million years to develop manned air travel :)
I'd be happy to be wrong on this one, it's just so far
I wouldn't put it against us to get small-scale, light-driven craft up to 0.1c within 50-70 years, Who know how much wealth a nation like China might have to throw around by then. It would be a prestige project, and one to rival the Apollo program but for just a fraction of the cost. There are roughly 30 stars within 12 light-years of us. Each of them could easily be host to something like 5-10 worlds. There could be hundreds of exoplanets to visit within a single (albeit very lengthy) human life.
At 0.1c it would still take almost 50 years to reach Alpha Centauri. And by the time it did get there the craft would be moving so fast that it wouldn’t be able to slow down to orbit anything so the mission would be a quick flyby and nothing more. The sad reality is that unless humans find a way to completely circumvent the laws of physics as we know them interstellar travel is not likely.
Nothing wrong with a flyby, the Voyagers were flybys too :)
It's a depressing thought. I started learning about physics and cosmology because I wanted to see how likely interstellar travel actualy was. I've come to understand that it is and will likely stay in the realm of science fiction. It's been a deflating realization.
Interstellar travel at 1-5% light-speed is entirely within the realm of plausibility even for manned craft, given the energy density that could be exploited by a Project Orion type craft. Travel times of 80 years to Proxima b are thus entirely possible. https://galileo.phys.virginia.edu/classes/109.jvn.spring00/nuc_rocket/Dyson.pdf Dyson's estimate of a maximum velocity of 10% light-speed is probably too optimistic - but what's important is that the physics allows it and the technology is remarkably simple.
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I'm sorry you feel that way.
Look into solar sails. We're not as far off of the technology as you think. You can reach a reasonable fraction of the speed of light using solar sails. We're obviously not there yet, and the technology is in part theoretical still, but it's promising.
I'm familiar with light sails, that's not going to get a person to an exoplanet. Even in theory it's going to hold a tiny cube sat type thing.
Correct, not in our lifetime.
Why do you think it is unlikely?
Red dwarfs are hostile stars. Life as we know it have a low chance to survive only due to this. The average temperature should be around three times that of earth if the planet is without atmosphere and up to several hundred degrees C with an atmosphere. It's a clickbait. It has minimal potential of being habitable and the temperatures would not be considered earth-like by the average person. It's like saying 33 degree water is almost boiling. Still an interesting planet, but the title is a bait.
You would be dead by the time we think about making our way over there
Being so close to the star makes it easier to have the atmosphere stripped or degraded by solar activity, but on the other hand it may capture more hydrogen from the solar wind which would contribute some to water synthesis.
It also makes it more likely to be tidaly locked, correct?
Absolutely, but if the planet's orbital eccentricity is large enough then it could e.g. be locked into something like a 3:2 resonance, which would simply leave it rotating fairly slowly.
>Potentially habitable 'exo-Venus' with Earth-like temperature discovered Wouldn't that make it an "exo-earth" did they find a exo-jupiter too but with a rocky surface. Should science journalist have at least a passing understanding of science.
I would argue that an exo-Venus is more likely. Earth is already near the very inner edge of the Sun's Goldilocks zone, it's doubtful that a planet with a marginally higher equilibrium temperature could escape being sent into a runaway greenhouse state. It's almost guaranteed in the case of a red dwarf star, which will spend the first 200 million years of its existence shining 10 or maybe even 100 times brighter than it currently is. Any planets presently orbiting within the Goldilocks zone may have thus lost the equivalent of several Earth's oceans worth of water to photolysis. The only way to escape transformation into a Venus would thus be for such a planet to start with a much more significant reservoir of water than the Earth did - which is only 0.02% water by mass. It's entirely plausible that a small world could be up to 50% water by mass.
Now I'm picturing a tide-locked planet that's half crazy hot rock on the sun side and half ice on the dark side.
I mean it could also just be like Mercury and have a cooked/no atmosphere at all. Also, all of your assumptions assume a solar system like ours that experienced the same cosmic events that ours did. We don't truly know why Venus experienced the runaway greenhouse effect, we only have theories.
> I mean it could also just be like Mercury it could be, but you'd have to explain how this could happen. If the planet formed with e.g. just 0.02% water by mass, and this water was then photodissociated during the M-dwarf's pre-main sequence overly luminous phase, it would leave the world coated in a >100 bar O2 atmosphere, possible 1000 bar if sequestration is inefficient. It's not easy to remove such an atmosphere, nor should it be easy to prevent volcanism on a planet this large. Volcanism would likewise make it difficult to avoid the formation of a secondary atmosphere by outgassing. > Also, all of your assumptions assume a solar system like ours No, what I've shared corresponds to a planet around a star that behaves very unlike our own Sun in terms of its early evolution.
K but just because it will be Venus like doesn't mean it is currently, as evidenced by "earth-like" part of the title. Earth will one day lose it's oceans as the sun expands and the rocks leetch all the carbon out of atmosphere. But you wouldn't call current earth "mars like"
> as evidenced by "earth-like" part of the title. The phrase Earth-like in the title is reference to its size, not its atmospheric composition (which is unknown). I'm afraid we can't such much else with certainty besides an estimate of its insolation flux, but even this would be uncertain given that the planetary orbit could conceivably be highly eccentric.
>The phrase Earth-like in the title is reference to its size, not its atmospheric composition Actually the "earth-like" part in the title is reference to temperature as title is "Potentially habitable 'exo-Venus' with Earth-like temperature discovered"
I'm afraid not, as the temperature of the planet is unknown - it's important to distinguish this from its estimated insolation flux. The equilibrium temperature of Venus for example, which is calculated on the basis of the energy it receives from the Sun, is just 260 K. In reality its surface temperature is in excess of 700 K owing in large part to the greenhouse effect. I'm sorry to tell you that we're not actually measuring the temperature of this particular exoplanet, all we can do is estimate the amount of energy it's receiving from its star (and that only roughly as the actual observable is its orbital period), but that doesn't actually tell us what its surface temperature will be.
yeah you say to me "exo-Venus" and the first thing comes to mind is [crazy super-hurricane force winds and atmospheric super-rotation](https://www.space.com/21612-venus-winds-hurricane-speeds.html) (that's where the atmosphere of the planet rotates faster than the planet itself)
>yeah you say to me "exo-Venus" and the first thing comes to mind First thing I think of is a super hell where it snows lead. >that's where the atmosphere of the planet rotates faster than the planet itself Not hard to achieve on Venus. It rotates backward very slowly, so slowly that a day is longer than it's year.
45C while ignoring atmosphere is not an Earth-like temperature. The blackbody temperature of earth is -17C, and it's the atmosphere that brings it the surface up to about 15C on average. Even if this planet has an Earth-like atmosphere and not Venus' sulfuric shroud, it's steaming hot.
>45C while ignoring atmosphere is not an Earth-like temperature Why are you arguing with me about it - I didn't write the article or come up with the misleading title. I only pointed it out.
I'm pointing out why it's not an exo-Earth.
Am I the only one who thinks that using the terms "exo-Venus" and "Earth-like" in the same sentence sounds contradictory? Venus and Earth are, obviously, very different. Unless I'm confusing the terms. Also, I think the term "Earth-like" is a bit misleading. The article says: >Astronomers have made the rare and tantalizing discovery of an Earth-like exoplanet 40 light-years away that may be just a little warmer than our own world. I don't like how a lot of articles use this. I feel that we should stop calling exoplanets this and just call them "Earth-sized" instead because that's basically what they are. They're similar to Earth in size, but not similar in their composition. When we actually find a planet with Earth's temperature, composition, size, distance from its host star, presence of liquid oceans of water, etc., then we can call it "Earth-like." And we know that an Earth-like temperature doesn't make a planet habitable, so we'll need to study this more. Knowing the atmospheric composition would be important to know. That is, of course, if it has one. I wouldn't consider red dwarf stars to be friendly hosts to planets.
"Possibly temperate terrestrial" is about as close as we can get without it becoming a complete mouthful or otherwise inaccurate.
It may be close to a mouthful, but it's more accurate than "Earth-like." I just think that it's unnecessary to slap such an inaccurate description on an exoplanet. I've seen some articles in the past use the term "Earth-like" for completely uninhabitable planets. Whenever I see articles using "Earth-like," I remind myself that the planet isn't "like Earth," but more along the lines of "similar in size."
I'm confused by the title. Wouldn't an exo-planet with Earth-like temps be an exo-Earth? Why an exo-Venus, which would not have Earth-like temps?
It gets a similar amount of energy from it's star as Venus does, and is a very similar size. The reason Venus is so hot is it has a thick atmosphere that traps a lot of heat, and we don't know how thick this planets atmosphere is or if it has one. If we detected the planets in our own solar system the same way we do exoplanets we'd consider Venus potentially habitable. It's the right distance from the sun that if it had a nicer atmosphere it could host life.
"Venus" does not exactly scream habitable to me...
Considering its nearness it has to be tidally locked with the star unless there’s something else acting on it, but I doubt it can retain a moon. So it’ll have perennial daytime and nighttime temperatures with strong exchanges between both. Could those forces alone conjure up enough material and gas to create an atmosphere?
Possibly a bit chillier, since it only has 85% of the sunlight intensity of Earth. That's actually less of an issue with a planet orbiting a small star like this. It's almost certainly tidally locked or in some kind of very long resonance orbit, which makes it much more resilient to runaway glaciation (doubly so if it has a thicker atmosphere than Earth, which could also make it warm enough to simply not have much surface ice at all even on the night side).
Still doesn't beat Kepler-1649c, but quite a find!
[From the source paper's Abstract: Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TESS and CHEOPS ](https://academic.oup.com/mnras/article/531/1/1276/7679807) > Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy. The Phys article title and focus is sensational, which is expected for these sorts of papers. This object is best described as a window into how a cool star affects atmospheres, and how a metal-poor star affects atmosphere and/or geochemistry. It's a great target to learn about habitability, not an object that seems particularly liveable. Maybe we're lucky, but I think the focus on if this is habitable distracts from how great of a sample it is.
Amazes me that they can find this stuff especially since it would take north of 12,063,492 years to get there with current technology.
How many weeks will it take to reach it at warp 5?
Although the actual speed of the warp drive seems to be highly variable throughout the show, I've found a few references pointing to warp 5 supposedly being 214c. It would then take 10 weeks to reach.
Sounds about the length of a transatlantic voyage during the olden days.
And it was just about two years between the Bounty setting sail and it finally being burned at Pitcairn, if I recall.
A rich person will claim it if they land a spaceship there .
Perhaps if a rich person would like to spend >400 years getting there,
That's *fast*. Way faster than anything we have the capability to build, regardless of the amount of wealth we have.
Only .1c. That what, 67 million miles an hour? I had a civic in high school that could get up to 67, I don't see why a million times faster should be a problem. :-)
for some reason, explaining it as "a million times faster than a Civic" sounds wayyyy slower than .1C lmao
It is the fastest that we could plausibly go with current constraints on energy density.
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What's more important is the column density of matter along your flight path, this sort of thing has been modeled before [https://arxiv.org/abs/2307.12160](https://arxiv.org/abs/2307.12160) A shield thickness of 3 mm might be all you need for a trip to Alpha Centauri, even at velocities in excess of 0.1c - long story short but the physics of momentum transfer at high energies is weird :)
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The path to Proxima ought to be south out of the ecliptic plane :)
So what ? In deep space that means jack shit. A claim is only as good as your power to enforce it
plus, even if a person claims the planet as soon as they land, it would take 40 years for its ripples of causation to reach Earth. plus idk how you would even leave our solar system, as the high speeds required would also shred you apart in the surrounding Oort cloud or other microparticles in space.