Question

Cosmic Dangers for Earth: During this class we have talked a lot about potential sources of danger for life on earth. Comment and describe for each of the scenarios below:

a) if it is likely to happen and if so,

b) if it’s likely to be dangerous to life on Earth

I. Sun will become a Red Giant and incerate Earth

II. Betelgeuse will go supernova

III. Gamma-ray burst is directed towards Earth

IV. Earth will be sucked into the supermassive black hole in the center of the Milky Way

Answer 1

Solution :

Part I : Sun will become a red giant and incinerate Earth

Yes, It is likely to happen that Sun will become a red giant and it would be definitely dangerous to life on Earth.

Red giants are stars which are in the final stages of stellar evolution. In approximately 5 billion years, Sun is expected to turn to a Red Giant consuming Mercury and Venus as it's outer layers expands in the solar system. It is still not clear whether it would destroy Earth but either way, life on Earth is threatened or to say specifically, life would not exist on Earth during this catastrophic event.

Part II : Betelgeuse will go supernova

Yes, It is likely to happen that Betelgeuse will become supernova but it wouldn't affect life on Earth.

Betelgeuse is approximately 600 LY away from Earth. It is expected to become a supernova within a million years. And when this event is likely to occur, it wouldn't affect Earth given the distance of separation between the two astronomical bodies. Even though it wouldn't be as bright as Sun, it would perhaps be the brightest star to watch out for in the night sky.

Part III : Gamma ray burst is directed towards Earth

Yes, Gamma ray burst that is directed towards Earth is likely to occur and it would be hazardous to the Earth's life forms.

Gamma ray burst is perhaps one of the powerful sources of energy. If a narrow beam of extremely focused gamma ray burst is directed towards Earth (within Milky way), they would easily destroy Earth's Ozone layer and expose the life on Earth to the harmful radiations of the Sun, thereby threatening the life of intricate ecosystems that exist on the planet. However, if a gamma ray burst is directed towards Earth beyond Milky Way, it poses no threat to the planet.

Part IV: Earth will be sucked into supermassive black hole in the center of the Milky Way

No, This is not likely to occur.

The black hole at the center of the Milky Way is too small to suck in Earth, which is many light years away. Only if astronomical bodies are dangerously close to the event horizon of the black hole, it is expected to get sucked into it. There are some stars that revolve around this black hole quite quickly at significant distance from it. The orbital motion of the planet Earth keeps it stable irrespective of the presence of a black hole in the center of Milky Way.

Note: Please comment below if you have any doubts....'