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Aug 11 15 9:46 PM
If dark matter is the most abundant form of mass, and has gravity, where are all the dark matter structures?“All enterprises that are entered into with indiscreet zeal may be pursued with great vigor at first, but are sure to collapse in the end.” -TacitusI can’t believe it’s been 100 editions, already, of our Ask Ethan series. Each week, you submit your questions and suggestions, and I choose my favorite to showcase and answer for the world. There were some very difficult ones to turn down this week, but I couldn’t say no to Jerry Mason’s submission:If dark matter has gravity, why doesn’t it form black holes or other structures?Dark matter sure does have gravity, and it sure doesn’t form black holes, dark matter stars, planets, or dark atoms. So why is this?Image credit: RHIC collaboration, Brookhaven, via http://www.bnl.gov/newsroom/news.php?a=11403.Imagine the Universe as it might have been back in the very, very early stages, before there were any black holes, stars, planets or atoms. All we had was a hot, dense, expanding “sea” of matter and radiation of all the different types allowed. By time the Universe has aged to be a few minutes old, the atomic nuclei are there, all the electrons are there, all the neutrinos and photons are there, and all the dark matter is there, too.They’re all flying around at incredible speeds, sure, but they’re also all exerting forces on one another. It’s true that they all feel the gravitational force (even photons, thanks to Einstein’s energy-mass equivalence), but gravity isn’t the only thing that matters here.
If dark matter is the most abundant form of mass, and has gravity, where are all the dark matter structures?
“All enterprises that are entered into with indiscreet zeal may be pursued with great vigor at first, but are sure to collapse in the end.” -Tacitus
I can’t believe it’s been 100 editions, already, of our Ask Ethan series. Each week, you submit your questions and suggestions, and I choose my favorite to showcase and answer for the world. There were some very difficult ones to turn down this week, but I couldn’t say no to Jerry Mason’s submission:
If dark matter has gravity, why doesn’t it form black holes or other structures?
Dark matter sure does have gravity, and it sure doesn’t form black holes, dark matter stars, planets, or dark atoms. So why is this?
Imagine the Universe as it might have been back in the very, very early stages, before there were any black holes, stars, planets or atoms. All we had was a hot, dense, expanding “sea” of matter and radiation of all the different types allowed. By time the Universe has aged to be a few minutes old, the atomic nuclei are there, all the electrons are there, all the neutrinos and photons are there, and all the dark matter is there, too.
They’re all flying around at incredible speeds, sure, but they’re also all exerting forces on one another. It’s true that they all feel the gravitational force (even photons, thanks to Einstein’s energy-mass equivalence), but gravity isn’t the only thing that matters here.
Read more @ https://medium.com/starts-with-a-bang/ask-ethan-100-why-doesn-t-dark-matter-form-black-holes-c5b6d90b1883
"What lies behind us and what lies before us are small matters compared to what lies within us." ~ Ralph Waldo Emerson ~
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