Question: How do we study stars?

Kevin Motherway answered on 8 Nov 2014:

Great question. I love a bit of Star Gazing. I have a tiny telescope but to be honest in Ireland binoculars are the job as by the time you’ve set up a telescope the clouds have come out. Once you let your eyes acclimatise you’ll see the stars have all different colours. Orion is one of the easiest constellations to spot that is high in the sky right now. Bottom right star (or his left foot) is a blue young hot star called Rigel: top left or his right hand is a red giant star called Betelgeuse that is long overdue to go kabalaaaam as a super nova. Look at the three stars coming down from his belt that form his sword and you’ll see a milky cloud which is a nebula where new stars are being formed and the gas and dust is all lit up a milky white. If you get a clear night point a camera ( an actual camera, not a phone, many have a starry night setting) at Orion on a stand or a bean bag and shoot for about 30 seconds. The image image will be slightly streaky showing you that in only 30 seconds the Earth has turned quite a bit relative to the stars, but you’ll see the difference in colours really really well.

If you capture light in a telescope and split that light up in a prism you’ll see stars have different spectrums and even dark lines where some wavelengths of light have been absorbed by elements in the stars body. One set of dark lines on all stars spectrums are for Helium and Hydrogen (we can get the same in a laboratory scale experiment) so that’s how we know that stars are basically huge nuclear fusion reactors converting hydrogen into heavier helium. We can also detect all the other elements that are made in stars by studying their spectra in the way.

That’s just looking at it in the visible light spectrum. To be a lazy astronomer why not working during the day! Of course you can’t see the visible light the stars during the day because our planets daylight drowns it out but the stars are shining all the time putting out the whole spectrum of light not just visible light. Other parts of the light spectrum like radio waves are visible all the time. Using a radio telescope (just like a big Sky TV dish) you can sit down and listen to/observe the non visible part of the spectrum day or night.

Jocelyn Bell Burnell is on of the true legends of Irish science and one of the real pioneers in radio astronomy. While a PhD student at Cambridge she discovered Pulsars, stars that are rotating and putting out intense radiation that sweeps across the cosmos like a beam from a lighthouse. These signals were originally dubbed LGM1 for “little green men signal no 1” as a joke because she couldn’t figure out where such a rhythmic signal could be coming from in space. Eventually having eliminated all the possible sources of interference she found it had to be from stars millions of light years away. A Nobel prize was awarded to her supervisors at Cambridge, but not her.

Boo hiss. Justice for Jocelyn now!