6 ms·

On the very final page is a table of distances. From 8 parsec to 70 parsec, so 28 to 250 light years or 240 trillion kms to 2170 trillion kms away (-ish) M

On the very final page is a table of distances. From 8 parsec to 70 parsec, so 28 to 250 light years or 240 trillion kms to 2170 trillion kms away (-ish) Many are comparatively cold. While most seem to be 400 Celsius plus, one (couldn't find in the article, but mentioned elsewhere) seemed to be -10 Celsius. Roughly (waving my hands and talking vaguely here) about 10% plus minus in distance and temperature.

etangent 6y ago
So that's actually further away than the closest star systems. Got freaked out for a second, because having hard-to-see massive objects near your sun system is scary!
- mynegation 6y ago
  Nearest known brown dwarf (actually a binary) Luhman-16 is farther away than Proxima but not by much (relatively speaking). It would be interesting to know if a theoretical smallest coolest brown dwarf would be detectable with the current technology.
  - skykooler 6y ago
    The line between small brown dwarfs and large planets is blurry. A brown dwarf twice the size of Jupiter and twelve times its mass could probably get inside our Oort cloud and have evaded detection.
- garmaine 6y ago
  Why would it be scary?
  - ivalm 6y ago
    If a brown dwarf scatters into the solar system it might dramatically shift orbits potentially making earth uninhabitable. To say nothing of a direct hit on anything, even hitting the sun might strip atmosphere from earth, hitting any planet would create world ending debris fields
  - jvm___ 6y ago
    Because eventually that body would have gravitational effects on our stable system and could throw everything out of whack.
    - garmaine 6y ago
      If it were in our solar system then it would be in a gravitationally stable arrangement--because if it weren't it would have already thrown things out of whack in the last 4.5 billion years.
    - kabdib 6y ago
      The solar system is actually not stable in the long term. Early planetary development was violent and chaotic, and the planets shifted around a lot more than you might think. We can't project orbits out indefinitely, either; multiple studies show that our ability to go out more than a few hundred million years are suspect and very dependent on starting conditions, which can obviously be easily perturbed by unknown bodies. Since we get star-sized approaches at Oort Cloud distances on the order of every few million years, that probably puts an upper bound on things.
      - btilly 6y ago
        Our next such approach is https://en.wikipedia.org/wiki/Gliese_710 https://en.wikipedia.org/wiki/Gliese_710 in 1.281 million years. However the rate at which such encounters happen varies greatly. We are in an orbit bobs up and down from the galactic ecliptic with a period of roughly 60 million years. There are more encounters near the ecliptic, with very few encounters when we are above or below. We cross the ecliptic about every 30 million years, and last did so about 3 million years ago. So we are still in the dangerous period. It is not entirely a coincidence that the dinosaurs were wiped out 66 million years ago, during another relatively dangerous period.
  - adenozine 6y ago
    Could be an object at high speed, waiting for the right gravity assist directly into us? Could be a strange object with capability to disrupt the sun somehow? Why would an object hitherto unbeknownst to us and close to the sun NOT be scary?
    - garmaine 6y ago
      > Could be an object at high speed, waiting for the right gravity assist directly into us? An object larger than Jupiter doesn't change its course because of chance encounters with other random small bodies. > Could be a strange object with capability to disrupt the sun somehow? This doesn't make physical sense. > Why would an object hitherto unbeknownst to us and close to the sun NOT be scary? Because it's had no observable effect on us for the last 4.5 billion years of our solar system's existence, and we've postulated nothing that would change this stable dynamical relationship?
      - adenozine 6y ago
        Then I guess the morons with careers in astrophysics are investigating it for no reason then. Beyond your wildly unfounded and I daresay naive assumption that the objects have had no effect on the solar system, perhaps they need to hear YOUR postulations. If only they were reading all of your grayed out comments, I see your dismissive and arrogant condescending remarks are leading to such fruitful insights and conversations. /s Feel better soon
        thombat 6y ago
        New things are interesting, and astrophysicists like investigating interesting things. If these brown dwarfs posed the slightest threat to us they'd be even more interesting than they already are.
        adenozine 6y ago
        Sure, I guess it's just irksome to assume that they aren't dangerous PRIOR to investigation. I mean, you wouldn't assume a random plant in the jungle is safe to eat, right? There's a lot of safe objects in space. There's a lot of safe plants in the jungle. Still, truth must be uncovered day by day. That's all I was meaning to convey.
  - wcoenen 6y ago
    In the scifi short story "a pail of air", the Earth is yanked away from the Sun by a dark star passing through the solar system. The Earth cools until all of the atmospheric gasses turn into solids and fall to the ground as layers of ultra-cold snow. It's one of the pieces of fiction that left a deep impression on me. Harsh winter days still remind me of it. http://www.gutenberg.org/ebooks/51461 http://www.gutenberg.org/ebooks/51461
    - garmaine 6y ago
      I suggest basing your view of reality on facts, not fiction.
      - Rebelgecko 6y ago
        The fact is that 250 light-years is not "near" the sun. Unless you're an astronomer, there's no practical difference between something that is 2 light years or 2,000,000 light years away. Both distances are equally unattainable. Saying that something is near "the sun" (as opposed to a more generic area like "the solar system") makes it sound like it's much closer than it actually is. Imagine if the article said that the stars were near "Dallas Texas". It would be equally true (±0.001%), but IMO the extra specificity is misleading
        FalconSensei 6y ago
        Exactly. They are not specifically near 'our sun'. They are near our system. The title (because of the specificity), seems to say that they are in our solar system, or so close that you could consider it like that
        waheoo 6y ago
        Yup, super weird sentence. It reads as if it is either between us and the sun, or close enough that you'd see it roughly up to the same distance we are from the sun.
      - samatman 6y ago
- throwaway316943 6y ago
  Don’t worry, there could still be somewhat smaller less detectable objects nearby.
eloff 6y ago
It's amazing that we could detect an object that cold, that small, at those distances. How does that work?
- doctoboggan 6y ago
  From my understanding they took 2 pictures of the same spot at different times and then had volunteers (“citizen scientists”) look at those pictures to see if anything moved. You can see some examples of the kinds of pictures in the paper linked in another comment above.
- unzadunza 6y ago
  I had to look it up, because I'm curious too. It looks like volunteers are given images from NASA's Wide-field Infrared Survey Explorer (WISE) telescope. The volunteers then just look for moving objects. https://www.zooniverse.org/projects/marckuchner/backyard-worlds-planet-9/about/research https://www.zooniverse.org/projects/marckuchner/backyard-wor...
  - nitrogen 6y ago
    I was unable to find a table matching wavelengths to visible temperatures in a bit of searching. Closest I could find is the chromaticity diagram on Wikipedia's Black-body Radiation article, which puts 1000K around 0.7nm red light. The WISE article lists 22μm as its longest wavelength, though that might no longer be attainable since WISE is out of coolant. If one can find out what blackbody temperature has its peak at 22μm, then we could maybe see how close to the edge of WISE's temperature range the 400C (673K) and -10C (263K) dwarves are. https://en.m.wikipedia.org/wiki/Wide-field_Infrared_Survey_Explorer https://en.m.wikipedia.org/wiki/Wide-field_Infrared_Survey_E... ---- Edit: found it: https://commons.m.wikimedia.org/wiki/File:Blackbody_peak_wavelength_exitance_vs_temperature.svg https://commons.m.wikimedia.org/wiki/File:Blackbody_peak_wav... Looks like 20μm is a bit below 200K, so if I'm interpreting this right, WISE should have had no temperature-related problem (leaving aside brightness) spotting a -10C brown dwarf.
    - eloff 6y ago
messe 6y ago
> From 8 parsec to 70 parsec Really minor correction, but 7.1±1.4 is the lower bound. 1 parsec is a tad over 3 lightyears, so it's a somewhat significant difference when the distances are that small. EDIT: corrected my correction
- PenisBanana 6y ago
  Ah, yes. A parsec is about 3.3 light years. I misremembered as 3.7 or 3.8 light years.

etangent 6y ago

So that's actually further away than the closest star systems. Got freaked out for a second, because having hard-to-see massive objects near your sun system is scary!

mynegation 6y ago
Nearest known brown dwarf (actually a binary) Luhman-16 is farther away than Proxima but not by much (relatively speaking). It would be interesting to know if a theoretical smallest coolest brown dwarf would be detectable with the current technology.
- skykooler 6y ago
  The line between small brown dwarfs and large planets is blurry. A brown dwarf twice the size of Jupiter and twelve times its mass could probably get inside our Oort cloud and have evaded detection.
garmaine 6y ago
Why would it be scary?
- ivalm 6y ago
  If a brown dwarf scatters into the solar system it might dramatically shift orbits potentially making earth uninhabitable. To say nothing of a direct hit on anything, even hitting the sun might strip atmosphere from earth, hitting any planet would create world ending debris fields
- jvm___ 6y ago
  Because eventually that body would have gravitational effects on our stable system and could throw everything out of whack.
  - garmaine 6y ago
    If it were in our solar system then it would be in a gravitationally stable arrangement--because if it weren't it would have already thrown things out of whack in the last 4.5 billion years.
  - kabdib 6y ago
    The solar system is actually not stable in the long term. Early planetary development was violent and chaotic, and the planets shifted around a lot more than you might think. We can't project orbits out indefinitely, either; multiple studies show that our ability to go out more than a few hundred million years are suspect and very dependent on starting conditions, which can obviously be easily perturbed by unknown bodies. Since we get star-sized approaches at Oort Cloud distances on the order of every few million years, that probably puts an upper bound on things.
    - btilly 6y ago
      Our next such approach is https://en.wikipedia.org/wiki/Gliese_710 https://en.wikipedia.org/wiki/Gliese_710 in 1.281 million years. However the rate at which such encounters happen varies greatly. We are in an orbit bobs up and down from the galactic ecliptic with a period of roughly 60 million years. There are more encounters near the ecliptic, with very few encounters when we are above or below. We cross the ecliptic about every 30 million years, and last did so about 3 million years ago. So we are still in the dangerous period. It is not entirely a coincidence that the dinosaurs were wiped out 66 million years ago, during another relatively dangerous period.
- adenozine 6y ago
  Could be an object at high speed, waiting for the right gravity assist directly into us? Could be a strange object with capability to disrupt the sun somehow? Why would an object hitherto unbeknownst to us and close to the sun NOT be scary?
  - garmaine 6y ago
    > Could be an object at high speed, waiting for the right gravity assist directly into us? An object larger than Jupiter doesn't change its course because of chance encounters with other random small bodies. > Could be a strange object with capability to disrupt the sun somehow? This doesn't make physical sense. > Why would an object hitherto unbeknownst to us and close to the sun NOT be scary? Because it's had no observable effect on us for the last 4.5 billion years of our solar system's existence, and we've postulated nothing that would change this stable dynamical relationship?
    - adenozine 6y ago
      Then I guess the morons with careers in astrophysics are investigating it for no reason then. Beyond your wildly unfounded and I daresay naive assumption that the objects have had no effect on the solar system, perhaps they need to hear YOUR postulations. If only they were reading all of your grayed out comments, I see your dismissive and arrogant condescending remarks are leading to such fruitful insights and conversations. /s Feel better soon
      - thombat 6y ago
        New things are interesting, and astrophysicists like investigating interesting things. If these brown dwarfs posed the slightest threat to us they'd be even more interesting than they already are.
        adenozine 6y ago
        Sure, I guess it's just irksome to assume that they aren't dangerous PRIOR to investigation. I mean, you wouldn't assume a random plant in the jungle is safe to eat, right? There's a lot of safe objects in space. There's a lot of safe plants in the jungle. Still, truth must be uncovered day by day. That's all I was meaning to convey.
- wcoenen 6y ago
  In the scifi short story "a pail of air", the Earth is yanked away from the Sun by a dark star passing through the solar system. The Earth cools until all of the atmospheric gasses turn into solids and fall to the ground as layers of ultra-cold snow. It's one of the pieces of fiction that left a deep impression on me. Harsh winter days still remind me of it. http://www.gutenberg.org/ebooks/51461 http://www.gutenberg.org/ebooks/51461
  - garmaine 6y ago
    I suggest basing your view of reality on facts, not fiction.
    - Rebelgecko 6y ago
      The fact is that 250 light-years is not "near" the sun. Unless you're an astronomer, there's no practical difference between something that is 2 light years or 2,000,000 light years away. Both distances are equally unattainable. Saying that something is near "the sun" (as opposed to a more generic area like "the solar system") makes it sound like it's much closer than it actually is. Imagine if the article said that the stars were near "Dallas Texas". It would be equally true (±0.001%), but IMO the extra specificity is misleading
      - FalconSensei 6y ago
        Exactly. They are not specifically near 'our sun'. They are near our system. The title (because of the specificity), seems to say that they are in our solar system, or so close that you could consider it like that
        waheoo 6y ago
        Yup, super weird sentence. It reads as if it is either between us and the sun, or close enough that you'd see it roughly up to the same distance we are from the sun.
    - samatman 6y ago
throwaway316943 6y ago
Don’t worry, there could still be somewhat smaller less detectable objects nearby.

eloff 6y ago

It's amazing that we could detect an object that cold, that small, at those distances. How does that work?

doctoboggan 6y ago
From my understanding they took 2 pictures of the same spot at different times and then had volunteers (“citizen scientists”) look at those pictures to see if anything moved. You can see some examples of the kinds of pictures in the paper linked in another comment above.
unzadunza 6y ago
I had to look it up, because I'm curious too. It looks like volunteers are given images from NASA's Wide-field Infrared Survey Explorer (WISE) telescope. The volunteers then just look for moving objects. https://www.zooniverse.org/projects/marckuchner/backyard-worlds-planet-9/about/research https://www.zooniverse.org/projects/marckuchner/backyard-wor...
- nitrogen 6y ago
  I was unable to find a table matching wavelengths to visible temperatures in a bit of searching. Closest I could find is the chromaticity diagram on Wikipedia's Black-body Radiation article, which puts 1000K around 0.7nm red light. The WISE article lists 22μm as its longest wavelength, though that might no longer be attainable since WISE is out of coolant. If one can find out what blackbody temperature has its peak at 22μm, then we could maybe see how close to the edge of WISE's temperature range the 400C (673K) and -10C (263K) dwarves are. https://en.m.wikipedia.org/wiki/Wide-field_Infrared_Survey_Explorer https://en.m.wikipedia.org/wiki/Wide-field_Infrared_Survey_E... ---- Edit: found it: https://commons.m.wikimedia.org/wiki/File:Blackbody_peak_wavelength_exitance_vs_temperature.svg https://commons.m.wikimedia.org/wiki/File:Blackbody_peak_wav... Looks like 20μm is a bit below 200K, so if I'm interpreting this right, WISE should have had no temperature-related problem (leaving aside brightness) spotting a -10C brown dwarf.
  - eloff 6y ago

messe 6y ago

> From 8 parsec to 70 parsec Really minor correction, but 7.1±1.4 is the lower bound. 1 parsec is a tad over 3 lightyears, so it's a somewhat significant difference when the distances are that small. EDIT: corrected my correction

PenisBanana 6y ago
Ah, yes. A parsec is about 3.3 light years. I misremembered as 3.7 or 3.8 light years.