Late! In the show this time, Dr Jonathan Pritchard tells us about exploring the dawn of cosmic structure with the 21cm line, Dr Michael Keith talks about pulsars in this month's JodBite, and your astronomical questions are answered by Prof. Tim O'Brien in Ask an Astronomer.
JodBite with Michael Keith
Dr Michael Keith is a lecturer at Jodrell Bank, working within the pulsar group, looking for new pulsars and using pulsars to detect gravitational waves. 2000 pulsars are currently known, but they each seem to have slightly different characteristics so more are needed to be found! Gravitational wave radiation is small ripples in space-time that travel out from heavy objects and in theory could be detected from Earth. These signals are very weak and have not yet been detected but astronomers are getting closer and closer every day. Gravitational waves from supermassive black holes in other galaxies affect the signals from pulsars and when examining a number of pulsars, if astronomers see the signal change from all pulsars at once this is a sign of a gravitational wave. Only a small number of pulsars are useful for gravitational wave experiments: the fastest millisecond pulsars. Finally, Dr Keith tells us about the so-called `diamond planet' orbiting a pulsar and the `fast radio bursts'.
Interview with Dr Jonathan Pritchard
Dr Jonathan Pritchard is a lecturer in astrostatistics at Imperial College London, and explores what we might be able to learn from radio signals transmitted during the first billion years of our Universe's history. We know little about the period between the emission of the cosmic microwave background and the formation of the first galaxies, and in this interview he explains how the characteristic radio emission from neutral hydrogen gas - known as the 21-centimetre line - can shed light on this time. Although originally transmitted at a wavelength of 21 cm, cosmological redshift spreads the radiation from earlier times out to longer wavelengths, giving us a chronology of its emission. Dr Pritchard talks about the 'Swiss cheese' pattern of this radiation across the sky, and how its statistical distribution can answer questions about when and how the structure of our Universe took shape. He discusses the ways of disentangling the signal from other astrophysical sources, and looks at current and future instruments which will detect it. Ultimately, he looks forward to a time when the 'cosmic hydrogen background' will be as thoroughly studied as the cosmic microwave background is today, filling in gaps in our understanding of an exciting time when the first stars began to illuminate the Universe.
Ask an Astronomer
Prof. Tim O'Brien answers your astronomical questions:
- The first question is from Russ Jenkins. He says 'If neutrinos are the up and coming frontier in observations, will it one day be possible to use them to observe further back in time than the Cosmic Microwave Background as the early universe was presumably transparent to neutrinos long before becoming transparent to photons?'.
- The next question is from Jerome Tremblay who says 'One question I got from a ten year old was What is Quantum Physics? How can you go about explaining the concept of that?'
- The third question is from Paul Saxton who wants to know whether the Mark 1 Telescope at Jodrell Bank has ever tried to look for the 'Wow Signal' and are there any plans to do any SETI observations at Jodrell Bank in the future?
- Final question for this month is from Peter Conway who asks 'If the tides are caused by the gravity of the Moon, why is there a high tide on the side of the Earth furthest from the Moon?'
Odds and Ends
Robonaut 2 (R2) is Nasa's experimental robot designed to do various tasks on the space station to assist the astronauts and has a humanoid form so the robot is able to use the same tools the astronauts use. Currently R2 is a torso-up only robot and must be attached to a specially designed post to work, but NASA is now developing legs for R2. These legs have a span of 9 feet, seven joints per leg and a special connector known as an effector where the feet would be.
The Chinese Chang'e 3 mission successfully landed on the Moon on December 14th. This is one of a series of lunar missions named after the Moon goddess from Chinese mythology. Chang'e 3 carries a rover named Yutu (Jade Rabbit, after the companion of the Moon goddess), China's first attempt at roving exploration. The mission will use ground penetrating radar to probe the structure of the lunar soil to a depth of 30 metres, and the lunar crust to a depth of hundreds of metres. Spectroscopic packages also enable studies of the chemical composition of the soil. Future missions will attempt sample return.
On 28 November, ESA announced that its selection for the second and third of three new large (L-class) missions to be launched later this century (along with the JUpiter ICy moons Explorer mission, an L-class mission which was selected in February). In 2028, ESA will launch its next-generation X-ray telescope, which will have the primary science goals of studying the X-ray gas in clusters of galaxies and studying the X-ray emission from the environments around black holes. In 2034, ESA will launch a gravitational wave observatory that will be able to detect gravitational waves for the first time.
|JodBite:||Dr Michael Keith and Indy Leclercq|
|Interview:||Dr Jonathan Pritchard and Mark Purver|
|Ask An Astronomer:||Prof. Tim O'Brien|
|Pantomime Author:||David Ault|
|Pantomime Cast:||Megan Argo, David Ault, Adam Avison, Leo Huckvale, Libby Jones, Indy Leclercq, Iain McDonald, Mark Purver and Christina Smith|
|Presenters:||George Bendo, Leo Huckvale and Christina Smith|
|Editors:||Adam Avison, George Bendo, Tim O'Brien and Christina Smith|
|Segment Voice:||Mike Peel|
|Website:||Christina Smith and Stuart Lowe|
|Cover art:||The landing site of Chang'e 3. CREDIT: NASA/GSFC/Arizona State University|