6 ms·

Astronomers discover sonic boom from powerful unseen explosion

95 points by LinuxBender 8y ago

onychomys 8y ago
This is super cool, but I'm not convinced that "sonic boom" is really the right term for it.
- ajross 8y ago
  It's a shock wave. Physically it really is the same thing. You can reasonably discuss the idea of "pressure" and a speed of "sound" in the interstellar medium, and what happens when a discontinuity like rapidly heated gas from a GRB starts to propagate. It's not the term astronomers would use, but honestly it's not wrong. My quibble would be that despite it being a common term, "sonic boom" doesn't really convey much information to a novice reader. Most people are just going to hear that as "big boom" and not understand that a shock wave is something distinct from a regular noise.
- everdev 8y ago
  I thought there was no sound in space? "Boom" sounds like a sound to me.
  - sp332 8y ago
    Well, Earth is in space, and there's sound here. There's no sound in a vacuum. As soon as you start adding material, like an entire collapsing star's worth, you can have sound.
  - wahern 8y ago
    https://gizmodo.com/there-actually-is-sound-in-outer-space-1738420340 https://gizmodo.com/there-actually-is-sound-in-outer-space-1...
ChuckMcM 8y ago
I sometimes think that they answer to the Fermi paradox is that the universe is an exceptionally dangerous place. Even when intelligence evolves, it has to dodge a whole bunch of bullets from the universe randomly sterilizing chunks with GRBs.
- clubm8 8y ago
  >I sometimes think that they answer to the Fermi paradox is that the universe is an exceptionally dangerous place. Even when intelligence evolves, it has to dodge a whole bunch of bullets from the universe randomly sterilizing chunks with GRBs. Or maybe since all this started with the big bang, there's some other civilization at a similar level of development at the opposite end of the universe - so far away we'll never cross paths? Or maybe there's only 1 intelligent form of life per universe, but many universes?
  - ChuckMcM 8y ago
    If you have read Fermi's paradox you know that it deals with only the visible stars in our own galaxy. The question he posed is why hasn't one of those planets orbiting one of those stars already created a galactic civilization that colonized the Milky Way. It could be that we're the first/only group to achieve sentience in the galaxy but the probability of that being true is astonishingly small. (Hence the paradox) The conjecture is essentially a "negative space illuminator" which is to say it suggests there is some piece of information that exists but is not currently known that would resolve this apparent paradox. If we were to discover that events happened every 'n' million years or so that sterilized stars in a 'm' thousand light year radius, a function of these two components would tell us for what values of n and m that would cancel out the survival and thus emergence of intelligent species.
    - stickfigure 8y ago
      How about: The physical laws of the universe just don't allow a practical way for us to interact. "Space is big." Science fiction authors can imagine all sorts of ways we could communicate or travel across interstellar distances, but really we have no idea how to build them. Maybe there just isn't some new discovery to be had.
rashkov 8y ago
It is really astounding how much we can "see" what's going on out there by combining our models of the universe with our recordings of the electromagnetic waves arriving at earth.
pp19dd 8y ago
Science Daily altered one sentence from the originally regurgitated PR, and I think it thoughtlessly corrupted its entire meaning. SD: "The blast generates two jets of gamma rays which travel out..." PR: "The blast generates two jets which travel out ... The jets emit gamma rays,..." Implication from their creative edit is that the blast itself shot out gamma rays (photons) at light speed, whereas the paper's authors actually described something else, a decades-long process of ejecta compressing and interacting to create gamma emissions. "The long time baseline of this event offers the best available constraint in afterglow evolution as the bulk of shock-accelerated electrons become non-relativistic." My understanding is that the famous '91 OMG particle (proton?) was theorized to have been generated by an expanding shock wave, except unlike here the scientific community then spent some time doubting their readings and being unable to re-verify the phenomenon. Conversely this new study observed such an event spanning from 1975-2017 using 7 different instruments. Original PR: https://www.dunlap.utoronto.ca/astronomers-discover-sonic-boom-from-powerful-unseen-explosion/ https://www.dunlap.utoronto.ca/astronomers-discover-sonic-bo... Paper: https://arxiv.org/abs/1808.08964 https://arxiv.org/abs/1808.08964
- 8bitsrule 8y ago
  Here's the WP article on that OMG particle (one particle with the energy of a thrown baseball): https://en.wikipedia.org/wiki/Oh-My-God_particle https://en.wikipedia.org/wiki/Oh-My-God_particle Since then, over 70 more like it have been seen; most seem to arrive from the Ursa Major direction, "from a distinct source near our galaxy and not from sources spread all over the universe." https://www.sciencemag.org/news/2014/07/physicists-spot-potential-source-oh-my-god-particles https://www.sciencemag.org/news/2014/07/physicists-spot-pote...

95 points by LinuxBender 8y ago

onychomys 8y ago

This is super cool, but I'm not convinced that "sonic boom" is really the right term for it.

ajross 8y ago
It's a shock wave. Physically it really is the same thing. You can reasonably discuss the idea of "pressure" and a speed of "sound" in the interstellar medium, and what happens when a discontinuity like rapidly heated gas from a GRB starts to propagate. It's not the term astronomers would use, but honestly it's not wrong. My quibble would be that despite it being a common term, "sonic boom" doesn't really convey much information to a novice reader. Most people are just going to hear that as "big boom" and not understand that a shock wave is something distinct from a regular noise.
everdev 8y ago
I thought there was no sound in space? "Boom" sounds like a sound to me.
- sp332 8y ago
  Well, Earth is in space, and there's sound here. There's no sound in a vacuum. As soon as you start adding material, like an entire collapsing star's worth, you can have sound.
- wahern 8y ago
  https://gizmodo.com/there-actually-is-sound-in-outer-space-1738420340 https://gizmodo.com/there-actually-is-sound-in-outer-space-1...

ChuckMcM 8y ago

I sometimes think that they answer to the Fermi paradox is that the universe is an exceptionally dangerous place. Even when intelligence evolves, it has to dodge a whole bunch of bullets from the universe randomly sterilizing chunks with GRBs.

clubm8 8y ago
>I sometimes think that they answer to the Fermi paradox is that the universe is an exceptionally dangerous place. Even when intelligence evolves, it has to dodge a whole bunch of bullets from the universe randomly sterilizing chunks with GRBs. Or maybe since all this started with the big bang, there's some other civilization at a similar level of development at the opposite end of the universe - so far away we'll never cross paths? Or maybe there's only 1 intelligent form of life per universe, but many universes?
- ChuckMcM 8y ago
  If you have read Fermi's paradox you know that it deals with only the visible stars in our own galaxy. The question he posed is why hasn't one of those planets orbiting one of those stars already created a galactic civilization that colonized the Milky Way. It could be that we're the first/only group to achieve sentience in the galaxy but the probability of that being true is astonishingly small. (Hence the paradox) The conjecture is essentially a "negative space illuminator" which is to say it suggests there is some piece of information that exists but is not currently known that would resolve this apparent paradox. If we were to discover that events happened every 'n' million years or so that sterilized stars in a 'm' thousand light year radius, a function of these two components would tell us for what values of n and m that would cancel out the survival and thus emergence of intelligent species.
  - stickfigure 8y ago
    How about: The physical laws of the universe just don't allow a practical way for us to interact. "Space is big." Science fiction authors can imagine all sorts of ways we could communicate or travel across interstellar distances, but really we have no idea how to build them. Maybe there just isn't some new discovery to be had.

rashkov 8y ago

It is really astounding how much we can "see" what's going on out there by combining our models of the universe with our recordings of the electromagnetic waves arriving at earth.

pp19dd 8y ago

Science Daily altered one sentence from the originally regurgitated PR, and I think it thoughtlessly corrupted its entire meaning. SD: "The blast generates two jets of gamma rays which travel out..." PR: "The blast generates two jets which travel out ... The jets emit gamma rays,..." Implication from their creative edit is that the blast itself shot out gamma rays (photons) at light speed, whereas the paper's authors actually described something else, a decades-long process of ejecta compressing and interacting to create gamma emissions. "The long time baseline of this event offers the best available constraint in afterglow evolution as the bulk of shock-accelerated electrons become non-relativistic." My understanding is that the famous '91 OMG particle (proton?) was theorized to have been generated by an expanding shock wave, except unlike here the scientific community then spent some time doubting their readings and being unable to re-verify the phenomenon. Conversely this new study observed such an event spanning from 1975-2017 using 7 different instruments. Original PR: https://www.dunlap.utoronto.ca/astronomers-discover-sonic-boom-from-powerful-unseen-explosion/ https://www.dunlap.utoronto.ca/astronomers-discover-sonic-bo... Paper: https://arxiv.org/abs/1808.08964 https://arxiv.org/abs/1808.08964

8bitsrule 8y ago
Here's the WP article on that OMG particle (one particle with the energy of a thrown baseball): https://en.wikipedia.org/wiki/Oh-My-God_particle https://en.wikipedia.org/wiki/Oh-My-God_particle Since then, over 70 more like it have been seen; most seem to arrive from the Ursa Major direction, "from a distinct source near our galaxy and not from sources spread all over the universe." https://www.sciencemag.org/news/2014/07/physicists-spot-potential-source-oh-my-god-particles https://www.sciencemag.org/news/2014/07/physicists-spot-pote...