3 ms·

A Multiwavelength Look at Proxima Centauri's Flares

57 points by JPLeRouzic 2y ago

lifeisstillgood 2y ago
I sometimes liken our civilisation as a reed mat floating across the pacific but with ants on it who have invented telescopes, and are trying their best to work out what sales are on at 5th Avenue - I love that we are “concerned” about atmospheric stripping millions of miles away - it gives me hope for those ants floating around
- wil421 2y ago
  What if we are the only ants in the ocean?
  - imglorp 2y ago
    Isn't that super unlikely? It seems like there are planets in most star systems. Even given what's been called a "gross underestimation" of 10^24 stars in the (observable) universe, even if you define some habitable zone based on our n=1 experience, even if you take some away based on the OP paper saying flares might make things a little harder at Prox, then that's still many Sagans* worth of planets, each of which gets a shot at growing telescope builders. That's a lot of chances. * "billions and billions"
    - dylan604 2y ago
      Even if...we'd still be too far away to communicate in any meaningful way. If today we were to send a message equivalent to a signal flare, it would not be received within any of our lifetimes and some within any of our species' lifetime.
      - Alive-in-2025 2y ago
        That's true. But there's a separate question, why no radio frequency evidence of other stars. I want to see some estimates of the liklihood of radio freq of some kind of communication in just our galaxy. How many stars might have earth-distanced planets from a sun - 6 billion in just our galaxy! Details below from a paper. If there were this many, I hope in my lifetime we hear from some, just evidence of other intelligent life. Here's a paper that estimates the presence of these planets from the Kepler space observatory. https://www.icds.psu.edu/how-many-earth-like-planets-are-around-sun-like-stars/ https://www.icds.psu.edu/how-many-earth-like-planets-are-aro... From 2019, it says using data from Kepler, they estimate that a close to earth sized planet (3/4 to 1.5 size of the earth) was in an orbit that could potentially have water vapor from a sun, orbital periods 327 to 500 days, with fairly large error bars: * somewhere in the range of 1 of every 33 stars to as high as one such planet for every 1 out of 2 stars in our galaxy. That's a large range, but given we have at least 200 billion stars in just our own Galaxy, that lower bound is about 6 billion stars with somewhat close to earth-distance planets, in just our galaxy. If this is over estimating by a million times, that's still 6 million planets in the earth like orbiting range. So let's make some noise, aliens. This source says estimates are 200 to 400 billion stars in the milky way. https://bigthink.com/starts-with-a-bang/how-many-stars-milky-way/ https://bigthink.com/starts-with-a-bang/how-many-stars-milky...
        dylan604 2y ago
        The universe is ~14 billion years old. We didn't come along until a few million years ago, and then it took just until a hundred to two hundred years ago to be able to actually broadcast our existence. So if some other civilization had a similar timeline but much earlier, their signal could have come and gone by the time we could detect it. Their star could have also already reached the point where it destroyed its planet the civilization was located, so we'd never know about them. It's the same fate our planet has in store for it as well. If there's any civilization that comes after Earth's demise, they'd never know we were here either.
        Alive-in-2025 2y ago
        Agree that other people could well have vanished by the time we randomly wander into their signals. The same is true for our radio. But I'm trying to focus on something else, the existence of other intelligent life is the key thing I hope to see. And we could destroy ourselves this afternoon of course. I don't care as much about do they exist still - that's icing on the cake. It's the idea that we aren't alone, that's the key to me. I'm certain there have been other intelligent civilizations in the universe because of the size, etc. We need evidence to know for sure.
    - pfdietz 2y ago
      > Isn't that super unlikely? We don't know enough to say whether it is unlikely or not. Pointing to lots of stars and waving your hands doesn't represent an argument.
indoordin0saur 2y ago
Been reading this gem of a blog for years. Happy to see it get some attention here.
0hijinks 2y ago
> Small M-dwarf stars ... operate through convection ... likened to what we see in a boiling cauldron of water. > Larger stars like the Sun show a mix of radiative transfer – photons being absorbed and reabsorbed as they make their way to the surface – and convection. > That enhances M-dwarf flare activity as their plasma is twisted and rotated, producing magnetic fields that snap open only to reconnect. This is the first post I've seen targeted toward generic geeks that explained it that way. It makes total sense, is really cool, and I'm glad they wrote this article.
- pfdietz 2y ago
  M dwarf stars, being fully convective (at least, the ones lighter than 0.35 Msun), cycle their entire material content through their cores. This is unlike the Sun, where the core is effectively isolated from overlying layers, and will run out of hydrogen while those outer layers still contain a great deal of it. As a result, and due to their low luminosity, M dwarf stars can go on burning hydrogen for a very long time, perhaps as long as 12 trillion years for a 0.1 Msun star, much longer than the universe has existed so far.

57 points by JPLeRouzic 2y ago

I sometimes liken our civilisation as a reed mat floating across the pacific but with ants on it who have invented telescopes, and are trying their best to work out what sales are on at 5th Avenue - I love that we are “concerned” about atmospheric stripping millions of miles away - it gives me hope for those ants floating around

wil421 2y ago
What if we are the only ants in the ocean?
- imglorp 2y ago
  Isn't that super unlikely? It seems like there are planets in most star systems. Even given what's been called a "gross underestimation" of 10^24 stars in the (observable) universe, even if you define some habitable zone based on our n=1 experience, even if you take some away based on the OP paper saying flares might make things a little harder at Prox, then that's still many Sagans* worth of planets, each of which gets a shot at growing telescope builders. That's a lot of chances. * "billions and billions"
  - dylan604 2y ago
    Even if...we'd still be too far away to communicate in any meaningful way. If today we were to send a message equivalent to a signal flare, it would not be received within any of our lifetimes and some within any of our species' lifetime.
    - Alive-in-2025 2y ago
      That's true. But there's a separate question, why no radio frequency evidence of other stars. I want to see some estimates of the liklihood of radio freq of some kind of communication in just our galaxy. How many stars might have earth-distanced planets from a sun - 6 billion in just our galaxy! Details below from a paper. If there were this many, I hope in my lifetime we hear from some, just evidence of other intelligent life. Here's a paper that estimates the presence of these planets from the Kepler space observatory. https://www.icds.psu.edu/how-many-earth-like-planets-are-around-sun-like-stars/ https://www.icds.psu.edu/how-many-earth-like-planets-are-aro... From 2019, it says using data from Kepler, they estimate that a close to earth sized planet (3/4 to 1.5 size of the earth) was in an orbit that could potentially have water vapor from a sun, orbital periods 327 to 500 days, with fairly large error bars: * somewhere in the range of 1 of every 33 stars to as high as one such planet for every 1 out of 2 stars in our galaxy. That's a large range, but given we have at least 200 billion stars in just our own Galaxy, that lower bound is about 6 billion stars with somewhat close to earth-distance planets, in just our galaxy. If this is over estimating by a million times, that's still 6 million planets in the earth like orbiting range. So let's make some noise, aliens. This source says estimates are 200 to 400 billion stars in the milky way. https://bigthink.com/starts-with-a-bang/how-many-stars-milky-way/ https://bigthink.com/starts-with-a-bang/how-many-stars-milky...
      - dylan604 2y ago
        The universe is ~14 billion years old. We didn't come along until a few million years ago, and then it took just until a hundred to two hundred years ago to be able to actually broadcast our existence. So if some other civilization had a similar timeline but much earlier, their signal could have come and gone by the time we could detect it. Their star could have also already reached the point where it destroyed its planet the civilization was located, so we'd never know about them. It's the same fate our planet has in store for it as well. If there's any civilization that comes after Earth's demise, they'd never know we were here either.
        Alive-in-2025 2y ago
        Agree that other people could well have vanished by the time we randomly wander into their signals. The same is true for our radio. But I'm trying to focus on something else, the existence of other intelligent life is the key thing I hope to see. And we could destroy ourselves this afternoon of course. I don't care as much about do they exist still - that's icing on the cake. It's the idea that we aren't alone, that's the key to me. I'm certain there have been other intelligent civilizations in the universe because of the size, etc. We need evidence to know for sure.
  - pfdietz 2y ago
    > Isn't that super unlikely? We don't know enough to say whether it is unlikely or not. Pointing to lots of stars and waving your hands doesn't represent an argument.

indoordin0saur 2y ago

Been reading this gem of a blog for years. Happy to see it get some attention here.

0hijinks 2y ago

> Small M-dwarf stars ... operate through convection ... likened to what we see in a boiling cauldron of water. > Larger stars like the Sun show a mix of radiative transfer – photons being absorbed and reabsorbed as they make their way to the surface – and convection. > That enhances M-dwarf flare activity as their plasma is twisted and rotated, producing magnetic fields that snap open only to reconnect. This is the first post I've seen targeted toward generic geeks that explained it that way. It makes total sense, is really cool, and I'm glad they wrote this article.

pfdietz 2y ago
M dwarf stars, being fully convective (at least, the ones lighter than 0.35 Msun), cycle their entire material content through their cores. This is unlike the Sun, where the core is effectively isolated from overlying layers, and will run out of hydrogen while those outer layers still contain a great deal of it. As a result, and due to their low luminosity, M dwarf stars can go on burning hydrogen for a very long time, perhaps as long as 12 trillion years for a 0.1 Msun star, much longer than the universe has existed so far.