Experimenting CLIL: school subjects in English / Science

The Life Cycle of a Star (3)

Góðan daginn, guys!

This time I said Good Morning in Icelandic! 😀

In the last episode we have seen how Laica has become a red giant while its bigger sister has become a super red giant. This time we are going to see what happens after these stages. They will be, as I said in the previous post, devastating events!

With the production of iron by nuclear fusion, the reactions able to produce energy come to an end. So there’s no force to contrast gravity, and again we have to make a distinction among three possible outcomes, depending on the mass of the star:

1. if the mass is lower than 0.5 solar masses, (remember?), it becomes a white dwarf, but an explosive white dwarf called Nova (ancient observers called it in this way because they thought it was a newborn star);

2. if the mass is between 0.5 and 8 solar masses it throws out external shells that become planetary haze (nebulas, areas where new stars will be born), while the nucleus becomes a white dwarf and then a Black Dwarf (we have never observed one because this stage requires more than 15 billions of years, more than the real age of the universe!)

3. if the mass is bigger than 8 solar masses, like our Laica, the star has an extremely intense explosion and enters the stage of Supernova.

So Laica has just become a Supernova: it reaches its highest brightness, and the highest instability, keeps ejecting dust storms, particles, energy…

Laica is a bit shy, so I couldn’t post one of its pictures, but this x-ray/infrared photo shows its friend Kepler, another big supernova . =)

Finally, after the ejection of enormous amounts of materials and energy, the star collapses and becomes:

1. a Neutron Star (if the mass is between 1,4 and 3 s.m.), also called Pulsar because of the emission of radio waves;

2. despite being old now, Laica does not surrender to its destiny, it doesn’t want to vanish and leave no sign of its existence in the universe. Maybe it feels like Tennyson’s Ulysses ( just to make an example 😉 ) and thanks to its mass, bigger than 3 solar masses, it becomes a mysterious and big Black Hole. It will continue to absorb and eject everything around it.

We don’t know much about this stage, some scientists think that there is a really big black hole at the center of our galaxy, the Milky Way, others think that black holes are “whormoles”, a sort of bridge that connect two regions of universe or maybe two universes! O.o

As a souvenir here is a picture that sums up all the stages of Laica and its relative’s life!

We have come to the end of our little voyage, I hope I’ve been exhaustive enough and of good company. I want to leave you with a thought:

a few years ago I thought that our sky was full of stars, billions of identical stars, that I imagined as twinkling little points. Now I know that when I was a child I wasn’t too far from the truth… only a few thousands of light-years far.. -.-

P.S. If you are interested in the topic, don’ forget have a look at Skantaman’s post on a newfound planet, the first very similar to our Earth! 😉

See you soon guys, Ryder


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