Astro dictionary

Astrobiology

The University College Institute of Astrobiology offers two definitions of the science: 1. The study of the formation and evolution of life on the Earth

2. The search for habitats and for life in the Solar System and in other planetary systems

Black holes and wormholes

Black holes are regions of space where the gravity is so strong that not even light can escape from it. They form when massive stars much bigger than our Sun collapse at the end of their life. Black holes are difficult to detect since they don't give out light like a star, but they are definitely thought to exist. Wormholes are like two black holes back to back (but without the crushing activity in the middle) thought to link different universes. At the request of Carl Sagan for his film Contact, they were investigated by Kip Thorne at the California Institute of Technology. He looked at whether it would be possible to travel interstellar distances via a wormhole, using them as a short-cut through space. He calculated that traversable wormholes could exist. At present, however, they are only theoretical constructs.

Magnetotactic bacteria

These were first discovered by Dr Richard Blakemore in 1975. The bacteria use a chain of ferrite particles (they contain iron) to line themselves up with the Earth's magnetic field. In the northern hemisphere they align themselves towards the North Pole and if you change the field around them, say by putting a stronger field the other way round, the magnetotactic

bacteria execute U turns!

Beagle 2's mass spectrometer

This will be able to look at the amount of carbon dioxide released when heating the Martian rock samples. There are slightly differently atoms of carbon called isotopes with slightly different masses and these exist in certain ratios when there has been life. The mass spectrometer will be able to determine the ratios of these different isotopes.

Doppler wobbling

This is a technique used to find new planets. A star with an orbiting planet will wobble a bit because of the gravitational pull from the planet. This makes the light given out by the star slightly change in wavelength as it wobbles. (This is just like when an ambulance comes towards you the pitch of its siren rises and as it goes away it descends. With light, the pitch is like the colour and so as the star wobbles away from us its colour will drop towards the red end of the spectrum and as it wobbles towards us it will shift towards the blue end of the spectrum.) For example, if you were trying to detect a planet around our Sun, you locate Jupiter as, due to its huge size, it makes the Sun wobble. It would take six years, however, to detect half a wobble, so it's a long process.

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