Blue Stragglers and the Polarised Universe

25 October 2011

Share

What are the mysterious blue straggler stars? In this month's Naked Astronomy we'll find out why some stars stand out from the crowd, as well as investigate the polarity of the universe. Plus, we hear the latest news from the Royal Astronomical Society, and take on your questions on rocket stability, detecting dark matter and our place in the universe.

In this episode

NASA photograph of one of the two identical Voyager space probes Voyager 1 and Voyager 2 launched in 1977.

01:18 - News from the Royal Astronomical Society

Dr Robert Massey brings us up to date with what's been happening at the Royal Astronomical Society...

News from the Royal Astronomical Society

Dr Robert Massey brings us up to date with what's been happening at the Royal Astronomical Society, including discussing mankind's interstellar legacy and what to look out for in the November night skies...

Atmosphere of Mars taken from low orbit

09:22 - New Missions to Mars

November will see the launch of two new missions to Mars - Phobos Grunt and the Mars Science Laboratory.

New Missions to Mars

November will see the launch of two new missions to Mars - the Russian Phobos Grunt; which will send samples of soil from the Martian moon Phobos, and NASA's Mars Science Laboratory, which will examine Mars with unprecidented clarity...

This stellar swarm is M80 (NGC 6093), one of the densest of the 147 known globular star clusters in the Milky Way galaxy. Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars, all held together by their mutual...

14:27 - How the Milky Way killed off its satellites

Models suggest the Milky Way should have far more dwarf galaxies orbiting it than we see - known as the the "missing satelites" problem. New evidence suggests a powerful blast of...

How the Milky Way killed off its satellites

Models suggest the Milky Way should have far more dwarf galaxies orbiting it than we see - known as the the "missing satelites" problem.  New evidence suggests a powerful blast of UV radiation my be to blame...

Will the Sun consume Earth before our galaxy collides with Andromeda?

Crepuscular rays emerging from behind a cloud

Why do sunbeams appear to spread out?

The correct name for this phenomenon is "crepuscular rays". It refers to the apparent spreading out from behind a cloud of sunbeams or shafts of sunlight when you view them from the Earth's surface.

It is, of course, an illusion. The Sun's rays are not issuing from behind a cloud and spreading out towards you: the Sun is so far away that the light rays reaching the Earth are effectively parallel. Instead, this "trick of the light" is caused by perspective. That is, things farther away look smaller. This is why train tracks appear to narrow, or converge, into the distance.

So when you look skywards and see sunbeams coming through a cloud, because the light patches at greater distance appear closer together, making the shafts of light look narrower.

Image of NGC 6397 taken by the Hubble Space Telescope, with evidence of a number of blue stragglers.

23:59 - The Origins of Blue Stragglers

Blue Stragglers are strange stars that don’t seem to fit the standard picture of stellar evolution. New research helps to shed light on their origins...

The Origins of Blue Stragglers
with Dr Christopher Tout, Cambridge University

Blue Stragglers are strange stars that don't seem to fit the standard picture of stellar evolution.  A paper published in Nature on the 20th of October by Aaron Geller & Robert Mathieu (see link below) helps shed some light on their origins.

Christopher Tout is the John Kooch-Adams Astronomer at the Institute of Astronomy in Cambridge, and a fellow of Churchill college.  He researches stellar evolution, and gives his perspective on the work.

 The Cosmic Microwave Background temperature fluctuations from the 7-year Wilkinson Microwave Anisotropy Probe data seen over the full sky. The image is a mollweide projection of the temperature variations over the celestial sphere.The average...

41:50 - The Polarised Universe

If you've seen a recent 3D film, you'll know that studying polarised light can be really helpful. The Cosmic Microwave Background is just the same - observing the polarity can...

The Polarised Universe
with Dr Jo Dunkley, Oxford University

If you've seen a recent 3D film, you'll know that the polarity of light is really important.  Separating different polarities can give us an altogether different view.  The Cosmic Microwave Background is just the same - observing the polarity can tell us about the history of the universe.

Andrew Pontzen speaks to Oxford University's Jo Dunkley...

Comments

Add a comment