In this Extra show, Dr Pierre Maxted tells us about the progress of the SuperWASP exoplanet search and Professor Glenn White discusses how observations at far infra-red and submillimetre wavelength can literally shed new light on our understanding of the Milky Way. Dr Tim O'Brien returns to answer your astronomical questions, and we report on some odds and ends from the world of Astronomy.
Interview with Dr Pierre Maxted
Dr Pierre Maxted of Keele University is involved in the SuperWASP project that searches for extrasolar planets, a burgeoning field of Astronomy. In this interview, he talks about using the transit method to find 'Hot Jupiters' - large planets orbiting close to their parent stars that move across the face of the star from our point of view. SuperWASP tracks millons of stars using a telescope with multiple CCDs (digital camera chips) attached to look for the small, periodic dips in brightness that would indicate a transiting planet. This relatively inexpensive method has yielded around 50 new planets so far, many of which can then be monitored by amateur astronomers with good equipment. Dr Maxted goes on to explain how infra-red measurements can allow us to observe the 'day side' of a planet as it passes behind a star, and describes how spectral measurements can reveal the chemical make-up of the planet's atmosphere and provide information about its internal composition. He discusses other ways to find and observe planets outside our Solar System, which together tell us about the mass, size and structure of each planet, and talks about how the growing list of known planets is revealing that there may be more habitable worlds in the Galaxy than was previously thought.
Interview with Professor Glenn White
Professor Glenn White of the Open University and the Rutherford Appleton Laboratory studies the Universe using the far infra-red and submillimetre light (including microwaves) that lies between the near infra-red and longer radio frequencies in the electromagnetic spectrum. Here he explains how this light allows us to see through the haze of dust in our Galaxy, and also to observe the heat emission of the same dust to reveal the temperatures of regions of the Milky Way. The telescopes that see at these frequencies must be in space to avoid the absorption of the Earth's atmosphere, and their detectors are ultra-cold to ensure that they generate very little heat radiation, which would swamp the signal. Professor White tells us about recent observations from the Herschel Space Observatory, which reveal that star formation often occurs in long, turbulent filaments of dust and gas, and he discusses how filaments appear to be a fundamental structure in the Universe on all scales.
Ask an Astronomer
Dr Tim O'Brien answers your astronomical questions:
- The first two questions this month arose as a result of Twitter discussions with @jodrellbank. First off: "Why is it so hot when the Sun is at aphelion?"
- The second Twitter-generated question was: "How come Neptune has only just completed its first orbit around the Sun since it was discovered in 1846?"
- Richard Pierce wrote in to ask: "Is it assumed that the Universe appears the same in all directions from all points, and, if so, what are the current leading theories on why this is so?"
- The next question is from Tim Newton, who is imagining two people racing around the Universe. One starts halfway out from the centre, the other at the edge. He wonders how long it would take them if they both travelled at 99% of the speed of light.
- Finally, Susan Kelly asks: "What is the difference between a thermal emission spectrum and a non-thermal emission spectrum, and is a thermal emission spectrum the same as a black-body spectrum?"
Odds and Ends
Atlantis set off on the 135th and final NASA space shuttle mission on the 8th of July. It took the Raffaello Multi-purpose Logistics Module and several tonnes of supplies to the International Space Station. The 30-year shuttle era will end when Atlantis lands on the 21st of July (not the 20th as stated in the show; the date was moved back after the time of recording). The five shuttles (excluding the test shuttle Enterprise) are the only spacecraft to have been reused in orbital flights around the Earth. Their replacements are likely to be privately built craft, produced by companies that are supported by NASA.
On the 11th of July (or the 12th!) Neptune completed its first orbit of the Sun since it was discovered in 1846. The precise time of Neptune's "birthday" has been calculated by one blogger to be 21:48 UT (Universal Time) on the 11th.
On the forum, RapidEye posted a link to a BBC webpage displaying the current positions of the Hubble Space Telescope, the Atlantis Shuttle and the International Space Station over the Earth.
On Facebook, David White posted a link to a spectacular photograph of the Lovell Telescope.
|Interview:||Dr Pierre Maxted and Mark Purver|
|Interview:||Professor Glenn White and Mark Purver|
|Ask An Astronomer:||Dr Tim O'Brien|
|Presenters:||Jen Gupta and Mark Purver|
|Editors:||Adam Avison, Tim O'Brien and Mark Purver|
|Segment Voice:||Liz Guzman|
|Website:||Stuart Lowe and Mark Purver|
|Cover art:||NASA's Atlantis begins the last ever space shuttle flight, launching from Cape Canaveral in Florida on the 8th of July, 2011. CREDIT:: NASA/Tony Gray and Tom Farrar|