Why these flashes of energy happen is a mystery. But by studying them, we’ve solved a big question about our universe. Dr Manisha Caleb explains.
The universe is vast and full of mystery and one that has been puzzling astronomers for a while now is fast radio bursts.
What are fast radio bursts
Fast radio bursts, or FRBs, as we refer to them, are these extremely energetic flashes in the sky that last about a hundred times quicker than the blink of an eye. However they’re invisible to the naked eye because they emit at the range of colors outside what the human eye can perceive. Now the furthest known FRB was produced 8 billion years ago and in comparison our solar system is only 4.6 billion years old, this means that when the light left the source we did not exist. So the Solar System, the Earth, life on Earth, humans, we all came about while the signal was traveling to us. We know of about 50 theories for what these could be. But the current leading favorite are magnetars so these are these extremely energetic objects which have massive and powerful magnetic fields.
Why do they matter
The signal bears the imprint of the medium that it travels through so the FRB encodes information about everything in its path. So as a result the radio data are a gold mine of information and this in fact helped us locate the missing matter in the universe. 95 per cent of the universe is dark energy and dark matter and five per cent is normal matter but 50 per cent of this normal matter is only accounted for and the remaining 50 per cent was considered missing until very recently. How is it missing? How can we just not know where it is? In a sense it’s invisible because it doesn’t emit or glow or absorb light but it does slow down radio waves which is where FRBs come in. We have found all of it. So it’s consistent with what we theorised but we don’t know how it’s distributed. There is always a ‘but’, that’s what research is.
We have observed at least once that they come from magnetars which are a type of neutron star but other than that we don’t know what produces them. The other reason why they’re really interesting is we can use these fast radio bursts to give us information about matter in the universe and the way that we do that is by comparing long and short wave bursts that come from the same origin point and calculate how long it takes for them to arrive at us now when they pass through matter that’s going to slow them down and depending on the material it’ll slow them down by a different amount. So we basically can look at all of that and figure out what’s out there and in doing this we have managed to find a whole lot of matter that we just thought was missing which is pretty cool.