The early universe was crammed with stars 10,000 times the size of our sun, new study suggests

An illustation showing a twinkling burst of starlight at the center of a turbulent field of crackling orange radiation and glowing black holes.
An artist's impression of the early universe, showing the first bursts of star and galaxy formation at the center. (Image credit: ESA)

 

The first stars in the cosmos may have topped out at over 10,000 times the mass of the sun, roughly 1,000 times bigger than the biggest stars alive today, a new study has found. 

Nowadays, the biggest stars are 100 solar masses. But the early universe was a far more exotic place, filled with mega-giant stars that lived fast and died very, very young, the researchers found.

And once these doomed giants died out, conditions were never right for them to form again.

The cosmic Dark Ages

More than 13 billion years ago, not long after the Big Bang, the universe had no stars. There was nothing more than a warm soup of neutral gas, almost entirely made up of hydrogen and helium. Over hundreds of millions of years, however, that neutral gas began to pile up into increasingly dense balls of matter. This period is known as the cosmic Dark Ages.

In the modern day universe, dense balls of matter quickly collapse to form stars. But that’s because the modern universe has something that the early universe lacked: a lot of elements heavier than hydrogen and helium. These elements are very efficient at radiating energy away. This allows the dense clumps to shrink very rapidly, collapsing to high enough densities to trigger nuclear fusion – the process that powers stars by combining lighter elements into heavier ones.

But the only way to get heavier elements in the first place is through that same nuclear fusion process. Multiple generations of stars forming, fusing, and dying enriched the cosmos to its present state.

Without the ability to rapidly release heat, the first generation of stars had to form under much different, and much more difficult, conditions. 

Cold fronts

To understand the puzzle of these first stars, a team of astrophysicists turned to sophisticated computer simulations of the dark ages to understand what was going on back then. They reported their findings in January in a paper published to the preprint database arXiv and submitted for peer review to the Monthly Notices of the Royal Astronomical Society.

The new work features all the usual cosmological ingredients: dark matter to help grow galaxies, the evolution and clumping of neutral gas, and radiation that can cool and sometimes reheat the gas. But their work includes something that others have lacked: cold fronts – fast-moving streams of chilled matter – that slam into already formed structures.

The researchers found that a complex web of interactions preceded the first star formation. Neutral gas began to collect and clump together. Hydrogen and helium released a little bit of heat, which allowed clumps of the neutral gas to slowly reach higher densities.

But high-density clumps became very warm, producing  radiation that broke apart the neutral gas and prevented it from fragmenting into many smaller clumps. That means stars made from these clumps can become incredibly large.

Supermassive stars

These back-and-forth interactions between radiation and neutral gas led to massive pools of neutral gas– the beginnings of the first galaxies. The gas deep within these proto-galaxies formed rapidly spinning accretion disks – fast-flowing rings of matter that form around massive objects, including black holes in the modern universe. 

Meanwhile, on the outer edges of the proto-galaxies, cold fronts of gas rained down. The coldest, most massive fronts penetrated the proto-galaxies all the way to the accretion disk.

These cold fronts slammed into the disks, rapidly increasing both their mass and density to a critical threshold, thereby allowing the first stars to appear.

Those first stars weren’t just any normal fusion factories. They were gigantic clumps of neutral gas igniting their fusion cores all at once, skipping the stage where they fragment into small pieces. The resulting stellar mass was huge.

Those first stars would have been incredibly bright and would have lived extremely short lives, less than a million years. (Stars in the modern universe can live billions of years). After that, they would have died in furious bursts of supernova explosions. 

Those explosions would have carried the products of the internal fusion reactions – elements heavier than hydrogen and helium – that then seeded the next round of star formation. But now contaminated by heavier elements, the process couldn’t repeat itself, and those monsters would never again appear on the cosmic scene.

Paul Sutter
Astrophysicist

Paul M. Sutter is a research professor in astrophysics at  SUNY Stony Brook University and the Flatiron Institute in New York City. He regularly appears on TV and podcasts, including  "Ask a Spaceman." He is the author of two books, "Your Place in the Universe" and "How to Die in Space," and is a regular contributor to Space.com, Live Science, and more. Paul received his PhD in Physics from the University of Illinois at Urbana-Champaign in 2011, and spent three years at the Paris Institute of Astrophysics, followed by a research fellowship in Trieste, Italy. 

  • Stephan Gunther
    " The first stars in the cosmos may have topped out at over 10,000 times the mass of the sun, roughly 1,000 times bigger than the biggest stars alive today, a new study has found.
    Nowadays, the biggest stars are 100 solar masses"

    Am I missing something ? 100 x 1000 = 100,000. That would make them 100,000 solar masses.
    Reply
  • Steamdude
    Stephan Gunther said:
    " The first stars in the cosmos may have topped out at over 10,000 times the mass of the sun, roughly 1,000 times bigger than the biggest stars alive today, a new study has found.
    Nowadays, the biggest stars are 100 solar masses"

    Am I missing something ? 100 x 1000 = 100,000. That would make them 100,000 solar masses.
    Caught that, too, but what's a magnitude of 10 among friends? ;-)
    Reply
  • zotrules
    They have no idea what they're talking about.
    1.4 solar masses and it's a black hole.
    10 000 sm it's a definite blackhole devouring everything even before bang.
    It is OK to fantasize about stuff that never happened and can never be observed, but numbers? simple arithmetic?
    And the guy gets paid!
    What a stupid stupid world.
    Come Lord Yeshua and fix this mess.
    Reply
  • Bruzote
    zotrules said:
    They have no idea what they're talking about.
    1.4 solar masses and it's a black hole.
    10 000 sm it's a definite blackhole devouring everything even before bang.
    It is OK to fantasize about stuff that never happened and can never be observed, but numbers? simple arithmetic?
    And the guy gets paid!
    What a stupid stupid world.
    Come Lord Yeshua and fix this mess.
    Well, please correct me if I am wrong, but a collection of gas much more massive than 1.4 solar masses will not form a black hole if it does not collapse within the Schwarzschild radius. The article mentioned that the original belief was that these gas clouds could not begin to collapse into protostar nebulae because of fragmentation of the cloud due to pockets of cooling. However, the article went on to mention how the study contradicted that belief, mentioning that the original gas was an inefficient radiator, so cold clustering would not happen. Instead, the clouds remained continous and were able to condense around a central point. However, this does NOT mean all of the gas in the cloud could condense to the point of causing collapse within the Schwarzschild radius. Instead, at some point, the pressure and heat inside the protostar's core would cause fusion, which would release radiation that prevented further collapse of the cloud. The star's ignition would lead to rapid burning and eventually supernova.

    Is there something wrong with that understanding?
    Reply
  • Bruzote
    Steamdude said:
    Caught that, too, but what's a magnitude of 10 among friends? ;-)
    You are forgetting there is a margin of mathematical error of plus/minus a factor of 10. ;-)
    Reply
  • Stephan Gunther
    zotrules said:
    Come Lord Yeshua and fix this mess.
    How's that working out ? I didn't know he preached about black holes.
    Reply
  • zotrules
    Bruzote said:
    Well, please correct me if I am wrong, but a collection of gas much more massive than 1.4 solar masses will not form a black hole if it does not collapse within the Schwarzschild radius. The article mentioned that the original belief was that these gas clouds could not begin to collapse into protostar nebulae because of fragmentation of the cloud due to pockets of cooling. However, the article went on to mention how the study contradicted that belief, mentioning that the original gas was an inefficient radiator, so cold clustering would not happen. Instead, the clouds remained continous and were able to condense around a central point. However, this does NOT mean all of the gas in the cloud could condense to the point of causing collapse within the Schwarzschild radius. Instead, at some point, the pressure and heat inside the protostar's core would cause fusion, which would release radiation that prevented further collapse of the cloud. The star's ignition would lead to rapid burning and eventually supernova.

    Is there something wrong with that understanding?
    Yes. Everything is wrong with that "understanding".
    Which original belief? Remember that "belief" until yesterday was a FACT over which they would have crucified people. Just like they will do over this one. This one you are calling understanding. The old one, belief.
    Not to mention that EVERYTHING you said was exclusively and only imaginary. And see how you talk confidently about your narrative, as if it were a fact and everyone is already informed and it is now common knowledge.
    Science is observation and experimentation, visible and testable. Then narrative is just detestable. Like a Jehova's Witness watchtower with the most paradisiacal and heavenly pictures to illustrate a moronic story.
    Reply
  • zotrules
    Stephan Gunther said:
    How's that working out ? I didn't know he preached about black holes.
    It's going very well so far. He hasn't heard any of us on this matter. We've been lucky.
    Black holes. He didn't preach about them, but their best description is, surprise surprise, given by Him, in His Book. Which description the official narrative stole, embellished it, tried every day to claim proof of them and guess what? to stun everyone, the official narrative itself, ties the black holes inexorably to the anthropic principle,
    Reply
  • Bruzote
    Stephan Gunther said:
    " The first stars in the cosmos may have topped out at over 10,000 times the mass of the sun, roughly 1,000 times bigger than the biggest stars alive today, a new study has found.
    Nowadays, the biggest stars are 100 solar masses"

    Am I missing something ? 100 x 1000 = 100,000. That would make them 100,000 solar masses.
    The author(s) have a technical excuse. The set of "biggest stars" has an undefined lower limit, and thus an undefined average as well. So, who is to say the average is 100 or 10 M?
    Reply