The First Stars in the Universe

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Star formation is one of the great unsolved problems in astronomy.  It is very difficult to simulate the star formation process with a computer mainly because it is a problem that spans many orders of magnitude in size, temperature and pressure, and must incorporate a variety of chemical processes. More simply put, there are hardly any spots to make approximations.  But solving star formation is still very important, because without stars, you wouldn’t be sitting here reading this blog today.  When massive stars explode (or supernova) they seed the space around them with heavy elements, such as the iron in your blood.  These explosions also help future generations of stars form.  Understanding how star formation works today keeps a lot of astronomers (both theorists and observers) very busy, but some astronomers like a challenge.  These astronomers study the first stars to ever form.

In a great article by John Wise of Georgia Tech, we learn about the formation of the very first stars.  After the Big Bang, most of the regular (that is, not dark) matter was found in hydrogen and helium.  However, in order to form stars, you need to bring large amounts of hydrogen together into a relatively small place.  This requires large pressures and low temperatures.  But in order for gas to cool, it needs to transfer energy out of the system.  At the present day, gas can cool relatively quickly because there are many avenues for energy to leak out.  This was not the case in the past.  The gas that formed the first stars was warmer, which leads to more material being available to the forming star, leading to more massive stars.

The article focuses on the advancements in simulating the formation of the first stars.  There have been some interesting improvements over the last few decades.  First, stars were an important source of light in the early ages of the Universe (it wasn’t just quasars).  Next, the first stars probably weren’t as massive as we first thought.  They tend to form pairs (or binaries) where the total mass of the system was roughly what we originally thought went into one star.  Finally, these stars probably aren’t around any more (or at least not in the Milky Way), but with more powerful telescopes (such as the JWST), we should be able to glimpse their influence on young galaxies.

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2 Comments

Filed under astro-ph, galaxies, stars, theory, Uncategorized

2 responses to “The First Stars in the Universe

  1. Janet Ebert

    After the big bang? But what made the Big Bang – where did that stuff come from? Janet

    • Hi Janet,

      Thanks for the question! All of the stars (and the problems that I describe in this blog) happened after the Big Bang. We know more about the properties of the Big Bang (i.e., how much energy was released, how quickly the Universe expanded) than “what” set the Big Bang off. But what we do know is that the Universe was a lot smaller and a lot hotter. As it expanded, it cooled, and the many of the first particles began forming. As the cooling progressed, more atoms began to form, and some of these atoms made their way into the gas that formed these first stars. Hope that helped!

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