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27th May 2007

Planets and Cosmology


Chris Smith

Helen Scales

This week on the Naked Scientists we will be venturing into space on an inter galactic mission to learn more about the biggest galaxies in space and the search for life on other planets.  Running the mission we will have Professor Carolin Crawford (University of Cambridge) who works with gases in galaxies and Dr Maggie Turnbull who looks for Earth-like planets and signs of life in the 'Goldilocks' zones among nearby stars (the Search for Extraterrestrial Intelligence Institute SETI).

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Interviews

 

The Search for Life in Outer Space

Dr Maggie Turnbull, Space Telescope Science Institute, Washington DC
 

The Shape of the Universe

Dr Carolin Crawford, University of Cambridge
 

Enceladus' Old Faithful

Dr Terry Hurford, NASA Planetary Geodynamics Laboratory
 

Science Update - Diseases of the Brain

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Kitchen Science

 

Measuring the Speed of Light


Measure the highest speed possible in this universe, just using objects you could find in your kitchen.

Questions

 

We've been sending out radio waves for about 80 years, and given that they travel at the speed of light, the nearest star that could hear them would be about 80 light years away. How many planets fall within that range?


 

I understand that there are two types of galaxies. Some have spiral arms and others an elliptical shape. What processes would form those two different types?


 

What determines the orbital distance from a star at which planetary material will coalesce? Is it just gravity?


 

If outer space is really cold, and the Sun is really hot, how close would you have to get to the Sun in order to be about room temperature?


 

Do all stars belong to a galaxy, or are there some stars which are orphans?


 

If what we term our universe was created by the big bang, does this mean that the whole universe was once a massive star that exploded, and if so could our universe be a small part of a bigger universe?


 

TV crime programmes often show DNA samples taken from suspects by swabbing the inside of their mouth. Human mouths are filled with bacteria, so the swab must collect non-human DNA as well as DNA from our food. How can human DNA be separated out from this?


Planets and Cosmology - More about this podcast

 Searching for Extraterrestrial life forms and working out how Galaxies formed 

This week on the Naked Scientists Radio Show and Podcast we will be venturing into space on an inter galactic mission to learn more about the biggest galaxies in space and search for life on other planets. Running the mission we will have Professor Carolin Crawford (University of Cambridge) who works with gases in galaxies and Dr Maggie Turnbull who looks for Earth-like planets and life among the nearby stars (the Search for Extraterrestrial Intelligence Institute SETI).

Intergalactic studies

Carolin Crawford studies the most massive galaxies in the universe; they're found in the core of clusters of galaxies, consisting of hundreds or thousands of galaxies which are held together by their mutual gravitational attraction.  Everyone knows that telescopes are devices through which you can see the stars, however, visible light is only part of the electromagnetic spectrum.  Studying celestial bodies can be done through various bands of the electromagnetic spectrum including radio waves and X-rays.  A tenuous gas (incredibly low pressure) fills the space between the galaxies.  The gas is very hot (temperatures of tens of millions of degrees) and emits light in the X-ray part of the spectrum.  In the core of the central galaxy there is a black hole who's immense gravity pulls in matter from its immediate surroundings.  Some of the energy released in this accretion process escapes as twin jets of energetic particles which are only visible in the radio wave part of the spectrum.  The galaxy is surrounded by long, spidery filaments of long molecular gas that glow in both infra-red and optical wavelengths.

All of the different components (which provide information at different wavelengths) interact with and influence each other, therefore you can only gain a full picture of the physics at play by combining observations from all the wavelengths available.  The radio jets push aside the X-ray gas to form galaxy-sized bubbles that rise upward through the cluster. These bubbles pull streamers of cold molecular gas out of the central galaxy in their wake; and so looking at the shape and movements of these filaments reveals a lot about gas moves within the cluster.

This research goes further than trying to work out how different components of galaxies move and interact.  Astronomers want to know how galaxies form, they think that they grew gradually as stars condensed from enormous ring of very hot gas, when the Universe was about a tenth its present age.

At present astronomers are not able to directly observe galaxies in the act of forming.  Instead they look at cores of clusters of nearby galaxies where they suspect the same physical processes are occurring.  Studying direct examples of these processes in action will have far reaching consequences to the much wider challenge of understanding galaxy formation.

 

The search for E.T.

Maggie Turnbull studies Astrobiology and searches for Earth-like planets and life among the nearby stars.  She's been working with SETI (the Search for Extraterrestrial Intelligence) and has designed their new target list, which is a catalogue of nearby stars that could potentially host “life” as we know it.  She supports NASA's Terrestrial Planet Finder mission and helps to identify the best stars to search for Earth-like habitable planets.  She's leading a team at the Space Telescope Science Institute (which runs the Hubble), to design a mission that would monitor the whole Earth from space (perhaps from the Moon) to discover how the Earth's light changes over the course of hours, days, seasons, and years.  She hopes to use that information to find planets like the Earth orbiting other stars, as well as to better understand Earth.




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