What is in the space between the stars?
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----------------- - 1822 - The largest stars the oldest stars.
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- Astronomers can calculate when celestial bodies are going to explode as supernovae. If they are bright blue stars and then they are bound to explode in the next million years. Astronomers do not hold themselves to too close accuracies.
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- There are large stars that astronomers have found that are at least 200 Solar Mass. These immense stars explode in an unusual manner because the are generating anti-matter at the Star’s center due to the immense gravity.
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- Still the luminosity of the large supernovae exceed astronomer’s calculations. Which tells us we are not using the correct math? Two theories try to explain this: The extremely bright light was heat radiation produced by a shock wave against the stellar wind.
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- The second theory involves radioactivity that was synthesizing new elements, radioactive isotopes that decay into stable isotopes. The decay injected energy into the expanding cloud of stellar debris causing the cloud to fluoresce.
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- Still another explanation involves “ pair production”. If the core of the star is hot enough nuclei and electrons emit Gamma Rays. If two very energetic Gamma Ray photons collide they can convert back into an electron and an anti-electron ( a positron).
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- When these events occur Density increases. This ignites the fusion of oxygen. Fusion releases nuclear energy which becomes a run away reaction. the reaction overcomes the star’s gravitational energy and the exploding supernova completely obliterates itself.
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- Most likely the first supernovae were ‘ pair production’ instability mechanisms because they were so massive, 100 to 1,000 Solar Mass. Such explosions were sure to have created the heaviest elements in the Periodic Table. All the way up to Uranium. The largest stars die in powerful explosions triggered in part by the production of this anti-matter.
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- The night sky bristles with spots of starlight in a background of dark sky. That part of the sky is dark only because our eyes are not sensitive enough to see all the dim light that fills the spaces between the stars.
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- That dim light is everywhere because it is the total output of billions of galaxies, containing billions of stars, burning over billions of years. Their brightness is dimmed to us because it is so diluted in the enormous expansion of space.
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- Another result of expanding space is the broadening of photon wavelengths. Light photons loose energy as their wavelengths get stretched traveling through expanding space. Astronomers call it reddening because visible light looses energy into the infrared spectrum.
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- If we could see it the brightest ( most intensity) of the extragalactic light has broadened into the microwave spectrum. Called the “ Cosmic Microwave Background “ ( CMB). It was not discovered until 1965. That light originated as Gamma Rays shortly after the Big Bang as soon as charged protons and electrons were cool enough to become neutral atoms and release the photons into space.
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- During these times of early discoveries a diffuse extragalactic background of X-rays was also discovered. Then, another observatory discovered a background of Gamma Rays. In total astronomers began to realize that the entire “dark” sky was awash in photons traveling in all directions at all different energy levels. The shorter their wavelengths the higher their energies.
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----------------------------- E = h * c / w
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---------------------------- Energy = constant / wavelength
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----------------------------- E = 1.989*10^-27 / w kg * m^2/sec^2
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- The dark sky contains the entire electromagnetic spectrum outside our eyes’ ability to see it.
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- The Cosmic Microwave Background was produced all at once 380,000 years after the Big Bang. This other extragalactic background is the result of billions of years of stars output starting with the first stars some 200,000,000 years after the Big Bang. All the stars since then have added to this background of photons filling our dark sky.
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- Astronomers are mimicking archaeologists as they study these stars going backwards in time. How did these first stars form?
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- The first stars are far too faint for astronomers to see today. But, they can learn a lot studying the chemistry of the oldest stars they can see, born 200,000,000 years after the Big Bang. these stars are referred to as second generation stars.
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- Most of the stars we see in our Milky Way Galaxy are 4 to 6 billion years old. The trick in determining the age of stars is identifying their composition. The oldest stars are composed of hydrogen, helium, and traces of lithium. These stars are approximately 200 million years old.
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- Stars born with heavier elements have nitrogen, iron, carbon composition as well. These stars formed 200-300 million years after the Big Bang already having the elements for carbon-based life.
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- The oldest living stars are going to have the faintest impurities, i.e. these heavier elements beyond hydrogen and helium. The metric used by astronomers is the ratio of iron to hydrogen,
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-------------------- Iron Abundance = 100 * Fe / H = %
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- Today, December 2015, astronomers have identified 50 stars that have less than 0.3% the iron abundance found in the Sun.
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- There are 6 stars that have less than 0.1% of this iron abundance. This would mean that these stars were born less that 500 million years after the Big Bang.
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- One star has been measured to have 0.00001% as much iron as the Sun. Known as Keller’s Star, it must have been born less than 200 million years after the Big Bang.
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- Current theories are that iron-poor and nitrogen rich second generation stars are progenitor stars 10 to 100 Solar Mass. These stars would likely become Blackhole after exploding as Supernovae.
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- Those iron-poor and nitrogen poor stars were likely 50 to 100 Solar Mass.
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- The very first stars were 140 to 260 Solar Mass. Their surface temperatures would exceed millions of degrees. Hot enough to produce Gamma Rays. Gamma Rays decay into electrons and anti-electrons in what is called “ Pair Production instability”. When radiation turns into particles the radiation pressure disappears, the star collapses to the center then rebounds into a giant supernova.
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- There are dwarf galaxies orbiting our Milky Way Galaxy that are rich with ancient stars. These galaxies were formed from gas of hydrogen and helium but did not collide with other galaxies to build full-sized galaxies. These dwarfs quit forming stars at the second generation stage. They are dated to be less than 100 million years after the Big Bang.
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- A 30 meter telescope would have 10 time as the light gathering over. That is what is needed to study these faint galaxies. Like superman it would help astronomers to have X-ray eyes. Stay tuned, an announcement will be made shortly.
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- Request these Reviews to learn more about stars:
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- #1116 - What are Astronomy’s standard candles
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- #1715 - The brightest stars, looking back in time.
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- #1670 - Super massive stars and super massive Blackholes.
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- #1555 - Determining the age of stars.
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- #1519 - How many stars are in the sky?
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- #1516 - Counting stars in the Infrared.
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- #1426 - Is the era of star formation over?
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- #1135 - Why do stars explode when they die?
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- #1134 - How do stars form to begin with?
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- #1082 - Name the stars.
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- #949 - The diversity of stars.
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- #907 - The biggest stars
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----- 707-536-3272 ---------------------- Sunday, January 31, 2016 -----
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