Electromagnetic Spectrum

Wednesday, 12 March 2008 @ 17:09 GMT

Electromagnetic Spectrum

Task 1

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What is the task

Produce a preview article for the programme "Meet the Astronomer - how do you detect space objects?"

Learning Objective

To know and understand the Universe we have to be able to "see it". Astronomers detect the electromagnetic radiation emitted by space objects to decipher Space. Information for this, again, can be found on the BBC website which has interviews with Sir Patrick Moore the presenter of 'The Sky at Night'.

The NASA website also supplies a great deal of information on the use of the electromagnetic spectrum in the detection of space objects.

The range of waves within the electromagnetic spectrum allows astronomers to gather information.

For example:

radio waves 'see' through clouds of dust to reveal objects
microwaves are the background 'noise' of the big bang
infrared penetrates dust into the centres of galaxies and starburst regions
visible light is the oldest and best known branch of astronomy allowing us to see space objects
ultraviolet is emitted by hot objects such as stars
X-rays are not absorbed by dust so hidden regions can be revealed eg the Chandra Observatory revealed a hidden huge black-hole in the centre of our galaxy
gamma-rays, which are given off by very hot objects or particles moving at very high velocities.

Using instruments that detect these ways, astronomers can detect objects in terms of colour, temperature, composition and velocity.

Information in the form of visible light, radio waves and electromagnetic radiation from space reaches the surface of Earth. However, astronomers have striven to improve the effectiveness of their communication receivers. This has been accomplished by:

rising above the Earth's atmosphere using aircraft and rockets
increasing the sensitivity of instruments, so the information communicated from the full range of space’s electromagnetic radiation can be accessed.

This has resulted in new instrumentation such as the Hubble Telescope, NASA's Swift and HETE satellites and in missions, for example NASA's launch of the New Horizons mission to Pluto, improving the detection of space radiation.

With the growth in use of satellites exploring space, candidates would have the opportunity to examine the methods of communication that might be available or improved on.