γ-ray Bursts

“Stars” – probably the most important objects in the universe. These objects do create all the elements. The elements we see, we feel, we touch and we are made up of are all first created in stars. Learning about the stars is a very exciting thing. This post will help to understand about γ-ray Bursts and their relationship with stars.

γ-rays are very dangerous. Whenever a nuclear bomb explodes, it releases loads of γ-rays. These rays, when exposed to human body create a disaster. It burns up our cells, which are the basic blocks of our body. Our universe also creates such γ-rays in its course. These γ-rays from universe were discovered in an unexpected way. Some foolish thoughts do result in great discoveries. Such a thing has happened here.

That was the time of Cold-War between Russians and Americans. Americans were very worried about the growing nuclear power of Russians. Americans wanted to have a check on the nuclear tests conducted by the Russians. So they made a satellite to detect the nuclear tests. But the most foolish part comes up here. Americans know that Russians will conduct their nuclear test at some place where they least expect. And so, the most probable place they thought was “the dark side of the Moon” (J yeah very foolish). So they made their satellite “Sterling Colgate” so powerful that it would be able to detect γ-rays from large distances. And from these rays, they can calculate the energy produced by the bomb and hence the power of the nuclear bomb using Einstein’s famous “E=mc2” principle.

Sterling Colgate was launched and nothing was observed till one day. Normally whenever nuclear tests are conducted, it was observed that the satellite picks up two spikes in the graph, a small one followed by a large one. But on that day something different was observed.

There were a large set of spikes. Scientists thought that it was the satellite that was malfunctioning. But it wasn’t. It was something like five thousand nuclear bombs, as powerful as the one that fell over Hiroshima and Nagasaki, were exploded at a time. And these rays weren’t coming from the earth, not even from the moon, but very far from us somewhere in the universe.

Scientists and astronomers made a lot of observations and calculations and deduced that these explosions were very far from us but within our galaxy “milky way”. This was deduced from the famous Einstein’s principle.

Any physical activity that happens in this universe must abide to Einstein’s equation “E=mc2”. So if such an explosion occurs some where far in the universe and that ray’s reaches the earth, the explosion must be very big and so is the mass of the object which results in the explosion.

We know that the largest objects in the universe are “stars”. And none of the stars, that were observed till now, could be as big as the explosion reaches from one end of the universe to another. So from this simple logic, the scientists deduced that the explosions are from our own galaxy.

But what results in these explosions???

Scientists have also deduced a theory for that. They said that the culprit was “The neutron star”. The neutron star is the star that is reaching the end of its life. When the star is nearing its death, it swells up and it burns out all the fuel it has and then because of its gravity, it stars getting compressed. A star which is going through this phase of its life is called as a neutron star.

Neutron stars do have high density, heavy weight and so a large gravitational pull. So when some celestial particles do move near such stars, it pulls them with its magnificent gravitational power and results in a collision. This collision may trigger γ-rays.

This theory was proposed and was very widely accepted. But is this right???

Any physical theory is always provisional, in the sense that it is only hypothesis: we can never prove it. No matter how many times the results of our experiments agree with some theory, we can never be sure that next time the result will not contradict the theory. On the other hand, we can disprove that theory by finding a single observation that disagrees with the predictions of the theory. Earth was considered as flat until the Aristotle observed that during the lunar eclipse the earth’s shadow on the moon was always round, which would be true only if earth was spherical.

So has this “theory of Neutron star for γ-ray bursts” also met the same end??

Will be Contd in the next post....