JOHN CROMWELL MATHER, whose vocation is to look at stars and planets through powerful telescopes, himself became a star attraction during the 97th Indian Science Congress held in Thiruvananthapuram from January 3 to 7, 2010. He mesmerised the big audience at the Space Summit, which was organised as a part of the Congress on January 4, on the topic From the Big Bang to Life in the Universe Past and Present, NASAs Astrophysics Projects. He is a senior Astrophysicist and cosmologist at NASAs Goddard Space Flight Centre, Maryland, United States, and Senior Project Scientist working on the James Webb Space Telescope.
Dr Mather and George F. Smoot of University of California, Berkeley, won the Nobel Prize in Physics for 2006 for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation. They analysed data from the NASA Cosmic Background Explorer (COBE) satellite, which studied the pattern of radiation for the first few instants after the universe was formed.
A press release from the Royal Swedish Academy of Sciences, dated October 3, 2006, which announced the Nobel Prize in Physics to Mather and Smoot said: This year the Physics Prize is awarded for work that looks back into the infancy of the universe and attempts to gain some understanding of the origin of galaxies and stars. It is based on measurements made with the help of the COBE satellite launched by NASA in 1989.
The COBE results provided increased support for the Big Bang scenario for the origin of the universe, as this is the only scenario that predicts the kind of cosmic microwave background radiation (of the universe) measured by COBE. These measurements also marked the inception of cosmology as a precise science. It was not long before it was followed up, for instance by the WMAP (Wilkinson Microwave Anisotropy Probe) satellite, which yielded even clearer images of the background radiation
Mather was listed in 2007 among Time magazines 100 Most Influential People in the World. He earned his PhD in Physics in 1974 from the University of California at Berkeley.
At the Space Summit, Dr Mather told the audience about the history of the Big Bang how the astronomer Edwin Hubble discovered in 1929 that the universe was expanding, which led to Hubbles Law that the farther away a galaxy is from the earth, the faster it is moving from the earth. This was completely unexpected. It was a spectacular discovery, he said. He revealed that about five billion years ago, the universe began to accelerate. The universe was accelerating faster and faster every year. We do not understand this, he said. These are mysteries of space. Another mystery was the physics of the sun.
In his address, he focussed on telescopes that are busy at work in the sky and those that will be launched. The operational telescopes included the Spitzer Space Telescope, which has been able to see galaxies very far away and clearly, the Hubble Space Telescope that has taken clear pictures of distant galaxies, and so on.
He spoke about the James Webb Space Telescope, a successor to the ageing Hubble Telescope, which will be deployed 1.5 million kilometres above the earth in 2014. Though the James Webb Space Telescopes expected lifespan is five years, NASA is confident that it will last 10 years.
The joint NASA-ESA (European Space Agency) mission called LISA (Laser Interferometer Space Antenna), will study the gravitational waves originating from collapsed objects in the sky. The collapse takes place when two Black Holes collide. There will also be an imaging telescope in the sky that will focus on X-rays. It will be an extraordinarily powerful telescope, said Mather.
Excerpts from an interview that he gave to Frontline during an intermission at the Space Summit:
Can you tell us about the work you did on the Big Bang, which won you the Nobel Prize?
I was one of the organisers of the COBE satellite, which was proposed in 1974 and launched in 1989 to measure the cosmic background radiation of the universe. This radiation remains the Big Bang itself. We measured the temperature and spectrum of this radiation extremely precisely, demonstrating that there is no theory other than this to explain the hot Big Bang theory.
So we know that the hot Big Bang occurred as nearly as can be proven in a scientific way. We also measured the hot and cold spots in this Big Bang radiation to understand why it is possible for galaxies to exist. We believe that the hot and cold spots we measured are the precursors of the clusters of galaxies that are now observed.
Under the action of gravity and the dark matter that produces the gravity, these hot and cold spots have evolved over cosmic time to produce the structure of the universe that we now see. So these two main measurements we made with the help of the COBE satellite are the basis of the Nobel Prize [that we received].
In your lecture you spoke about the James Webb Space Telescope (JWST). You mentioned four major themes on which astronomers will work, using the JWST. What are they?
The JWST is a project of NASA in partnership with the European Space Agency and the Canadian Space Agency. We are obtaining the telescope from Northrop Grumman Aerospace and their worldwide network of partnerships. It is planned to launch it in 2014 to a location, 1.5 million km above the earth, called the Sun-Earth Lagrange point, L-2. It is a perfect place for the telescope to be protected from the heat of the sun.
The telescope is larger than the Hubble Space Telescope. After deployment, it will have an aperture of 6.5 metres, with a sun-shield which is as large as a tennis court. This huge umbrella allows the telescope to reach a temperature of 40 Kelvin so that it can observe the infra-red radiation. If the telescope were to be as warm as human beings, it will be emitting (confusing) infra-red radiation and will prevent us from observing.
There will be many topics people would like to observe using the telescope: the formation of first objects after the Big Bang the first stars and the galaxies; the evolution of galaxies as they change with time; the formation of stars and planets; and the evolution of the planetary system, such as the solar system, so that it is possible to know whether other planets can support life the way the earth can.
How do you plan to deploy the JWST 1.5 million km away? You said you would use the Ariane V launch vehicle. The U.S. Space Shuttle deployed the Hubble Space Telescope, but just some 100 km away from the earth.
Ariane V is the basic workhorse rocket. It has a primary and secondary section. It is a standard product that the European Space Agency can obtain from Arianespace, which is a commercial organisation in Europe. Very similar to other launches, the telescope goes directly to the deployment point.About 1.5 million km away?Yes, it goes directly there.
You spoke about the existence of several super-earth around the sun. What exactly are these super-earth?
Superearth is an idea that there are objects similar to the earth but larger. An object larger than the earth will have a different internal structure. They are considerably more massive. It will be easier for us to detect them because they are bigger and heavier. Several have already been discovered by ground-based astronomers, using the Doppler-shift technique and the transit technique.
The Doppler shift technique measures the change in the velocity of the stars due to the gravitational pull of the planet. The other technique is to wait for one mass of rock from the star so that during the course of an hour or two, as the planet moves between us and the parent-star, we see that the light is diminished by some amount. Both methods have already been used for some already detected objects.What is the Europa mission?
It is a planned mission to go [send an orbiter] to the satellite Europa around Jupiter. Europa is a very interesting satellite and was discovered by Galileo Galilei in 1609. So it is 400 years since it was discovered.
It is very interesting because it is warm and it has an ocean, with ice covering the ocean. The ice is active. It moves around. One can see the cracks between the chunks of ice and the dark coloured banks between the chunks of ice. So, it is clearly a place of great interest for fundamental science. It is conceivable that it has life
It is possible that the ocean underneath the ice has life. It is not photosynthetic life. It is not like algae because it is unlikely that there is enough sunlight there. It is possible for chemical life to exist, as it does on the earth, that consumes iron and sulphur or some other chemical.
It is a very interesting and intellectual question whether the conditions we have on the earth are required for life to exist in strange, exotic locations such as Europa.
Water molecules were discovered recently by payloads of NASA and the Indian Space Research Organisation on board Indias Chandrayaan-1 mission to the moon. How do you assess the significance of this discovery?
Actually, we dont get to know very much about this water. It is more than what was expected. It has been found in some of the great, cold locations of the moon. It seems to be underground a little bit. It is protected. So scientists are yet to understand this. We do not know why it is there. It can be water fallen on the moon from comets. It can be water formed on the moon from solar winds hydrogen comes out from the sun and protons invade themselves into rocks, and chemical reaction can occur inside the rocks. Water molecules can move around the surface of the moon and then go from one place to another. It is a very interesting subject.
We do not know whether there is enough water to be useful to astronauts. It is pretty easy to bring water from home [the earth] It is not easy to use the water found on the moon.
Professor U.R. Rao, former Chairman, ISRO, has said that it may take another 1,000 years to colonise Mars. Do you think it is an accurate prediction? When Mike Griffin, former NASA Administrator, attended the International Astronautical Congress in September 2007 in Hyderabad, he said NASA may send astronauts to Mars by 2035.
There is a difference between going there for exploration and colonising it. Mars is an extremely hostile place. It is difficult to live there. There is no air. We cannot breathe the air. There is no protection from the cosmic rays.
An astronaut living on the surface of Mars for six months or a year could die from the cosmic rays. So colonisation is difficult. We can live underground but it is not so much fun. We do not know whether it is possible to produce agriculture on the surface of Mars. It seems unlikely. It is too cold. It is too dry. Maybe some way will be found to create food and sustain life there. But right now it is too difficult. It is a huge engineering project.
Would you like to highlight any project that you are working on?
I have a small participation in some missions. The WISE mission [NASA-funded explorer mission that will provide a vast storehouse of knowledge about the solar system] has just been launched.
It is Wide-field Infra-red Survey Explorer. They will make a catalogue of the entire sky with infra-red. That is one. I have interest in many others. But they are hypothetical. Not begun yet.
What are the chances of finding life on another planet the Search for Extra-Terrestrial Intelligence (SETI)
It is unlikely that we will find it with SETI. But we should try.What work will SOFIA telescope do?
SOFIA Stratospheric Observatory for Infra-red Astronomy that is what the letters mean. It is a 2.7 metre telescope that looks out through the side of an airplaneIt has had a test-flight. So far no scientific results have been obtained. First of all, they have to prove that it is safe to fly an airplane with a big hole on its side and make the telescope work as well.What will it observe?
It is a general observatory for many purposes. It is capable of observing all wavelengths from visible wavelengths to far infra-red. The instruments are not yet on the telescope.
Why has infra-red become so important now? People talk about infra-red image seekers that can take pictures of satellites in low-earth or polar orbits.
It is because it is new for us. We do not know what observations will show up. We also have new technologies capable of observing the infra-red that could not be measured earlier. So we need telescopes that are large, cold and out in space, and that was difficult. It is now possible.