Date: March 1, 2011
Title: Supernovae at a Glance
Podcaster: Thomas Hofstätter
Description: In this podcast, we are going to discuss the topic of supernovae in the universe. It gives a short overview on the science, development and history of supernovae and novae as well as their influences on humans like us.
Bio: Born in 1993 near Vienna, Austria, Europe. Upper High School with focus on Computer Science.Interested in extreme small and extreme big, devious and uninvestigated things. My main aim is to bring astronomy to public and to establish secular interest in astronomy, physics and mathematics. Host of :: The Hidden Space Project :: at http://hidden-space.at.tf.
If you have any questions, comments or suggestions to the podcast, feel free to write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf!
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Transcript:
Hello and welcome to this episode of 365 Days of Astronomy. My name is Thomas Hofst‰tter and I am the hoster of :: The Hidden Space Project :: at www.hidden-space.at.tf.
[Leon:] And I’m Leon Dombroski from the state of Connecticut in the United States.
In this podcast, we are going to discuss the topic of supernovae in the universe. It gives a short overview on the science, development and history of supernovae and novae as well as their influences on humans like us.
[Leon:] The reason for a star like our sun and all the others in the universe to shine is the mere fact that it is “burning” atoms. It’s the same process that can be found in nuclear power stations and that makes nuclear bombs so dangerous.
The first and simplest reaction is the fusion of Hydrogen to Helium. According to the size of the star, it’s possible to change four Protons into one Hydrogen-Atom. Two positrons, two neutrinos and energy are emitted during this process. This energy makes the star shine.
[Leon:] Larger stars are also able to produce heavier elements like Carbon, Neon, Oxygen, Silicon and Iron. This happens in the so-called CNO-Cycle. Larger stars are also able to shine brighter but therefore have a shorter life. Smaller stars need much longer to burn all the energy they contain.
When a star has burned all it’s energy, there are different shells named after the elements they contain. In the center, there is iron. Helium and Hydrogen are the outermost. When the core of the star becomes empty because most of the elements are burnt, the gravitational force isn’t able to hold the star’s matter together which causes the outer shells to be pushed out into space due to the centrifugal force.
[Leon:] The innermost shells collapse under the force of gravity and build a very dense object that might even be a black hole when the star had been heavier. Former stars up to 20 times the mass of the sun usually form neutron stars; stars that had been even heavier form black holes. That’s the main principle of what scientists call a “nova” or “supernova”.
Supernovae are also the only way to produce the elements; our earth and we humans are made out of. The big bang was only able to produce three elements: Hydrogen, Helium and Lithium. Supernovae have produced all the other elements heavier than Oxygen.
[Leon:] During one year, scientists estimate that there are about 30-50 novae in our Milky Way. At the time, scientists usually detect about 10 of them due to the fact that they are quite faint at some times. Remnants of supernovae were once wrongly called “Planetary Nebula” because they looked like planets through older telescopes.
Supernovae are much more infrequent and only occur twice in a century. They produce high amounts of gas that mostly is collected again by the resulting neutron star or black hole. Supernovae usually shine brighter than other celestial objects and hence can be seen with the naked eye.
[Leon:] That’s also the reason why the very first supernova had been detected on July 4, 1054 (!) by Chinese and Arab observers. It’s now called SN 1054 after the year it had been detected. The former star was in the constellation Taurus.
The supernova remnant has been catalogued by Charles Messier in 1758 and got the number 1 in his catalogue. Hence, it’s now called Messier 1 or M1. Other names are NGC 1952 and Sharpless 244 according to the catalogues as well as Crab Nebula.
[Leon:] Other historical supernovae are SN 1572 which was observed by Tycho Brahe and SN 1604 which was observed by Johannes Kepler. The difference in time of the two supernovae is surprisingly small.
Nowadays, it’s also possible to detect novae and supernovae outside our own Milky Way. Each year, scientists find about 20 supernovae in our neighbor galaxy Andromeda (M31). It’s expectable that also stars like Rho Cassiopeia, Betelgeuse, Antares, Spica and others are going to supernova during the next decades and centuries.
That’s it for today. I hope, you enjoyed it. If you have any questions, comments or suggestions, write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf.
Thanks for listening and clear-skies!
[Leon:] Good bye for now!
End of podcast:
365 Days of Astronomy
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