The director of the Space Physics Laboratory at the Vikram Sarabhai Space Centre on the significance of phenomena like airglow, electroglow, aurora, and moon and Mars missions
Mumbai: Anil Bhardwaj, director of the Space Physics Laboratory at the Vikram Sarabhai Space Centre in Thiruvananthapuram, is the only Indian scientist who has had a payload in every Indian space mission. His experiments on Chandrayaan 1, India’s first moon probe, and the Mars Orbiter Mission have revealed new insights into solar wind interactions on the lunar surface and yielded new information about the Martian atmosphere. A recipient of the Infosys Prize 2016 for physical sciences, which carries a cash prize of Rs65 lakh, Bhardwaj spoke in an interview about his work, views on extraterrestrial life and God. Edited excerpts:
When, and how, did you fall in love with science?
As I was growing up, I began observing the various phases of the moon, and how it revolves around the Earth. As a child, I also read a lot about the difference between stars and planets—that stars twinkle and planets don’t. This was more of a hobby initially—at least till I did my graduation and postgraduation when I began liking physics over mathematics. The reason is that physics gives you an idea of the Why and How of things.
Your PhD work at the Banaras Hindu University was on studies of aurora (natural light display in the sky) and airglow (faint emission of light by a planetary atmosphere) processes on outer planets and comets. Explain the significance of this study.
I started my PhD in 1987. Just a year earlier, the comet Halley (It was last spotted in 1986. It returns to Earth’s vicinity every 75 years.) came close to the inner solar system and we could see it from Earth. Around that time, there were also five space missions that were planned by Europe, Russia and Japan to explore the comet. Hence, 1987 was the period when there was a lot of interest in cometary science. That sparked an interest in me and my supervisor told me to work on coma—basically the atmosphere of a comet—and the processes happening therein and how the Sun interacts with comets. That’s how I got involved in exploring how auroras are produced on planets and how they differ on smaller bodies like comets.
Around that time, we also had some results coming out from the Voyager fly-bys—a space probe launched by Nasa (National Aeronautics and Space Administration) on 20 August 1977 to study the outer planets—which spoke about new characteristics of auroras on outer planets. That sparked my interest further since planet Uranus was visited by Voyager (which made its closest approach to Uranus on 24 January 1986) and the results were coming out in 1987.
What was the significance of these findings?
On Earth, auroras are predominantly seen in the high latitude (Arctic and Antarctic) regions. In the case of outer planets, especially Uranus, we found some processes happening at lower latitudes (not in the poles) and those were very different from the auroras on Earth. Since these planets are made of helium and hydrogen unlike Earth that is dominated by nitrogen and oxygen, we set out to explore whether it was hydrogen or helium that was causing the phenomenon. We ended up giving the phenomenon a new name—electroglow. One of my first few papers (bit.ly/2k05qgW) was on this subject. The implication is that when we study other planets, we get a lot more information than if we study only planet Earth.
What results did your experiments on Chandrayaan 1 and the Mars Orbiter Missions yield?
On Chandrayaan 1, we had an instrument called SARA (Sub-keV Atom Reflecting Analyser), which was an Indo-Swedish collaborative instrument with contributions coming from Japan and Switzerland. This was the first of its kind instrument used to study any planetary body, and being flown to a mission for the first time. SARA looks for neutral atoms coming from the lunar surface due to the interaction of solar winds, which is basically plasma largely made up of protons and coming and hitting the lunar surface. We conjectured that these high energy particles that emanate from the Sun and hit the lunar surface—because the moon does not have an atmosphere—will help us identify minerals on the lunar surface.
To our surprise, we found that the plasma hitting the lunar surface itself was getting back scattered as neutrals. Nobody expected that so we wanted to understand the “Why" of it. We discovered that these protons from the solar wind which hit the lunar surface do not touch the lunar surface where the moon has small magnetic fields known as magnetic anomalies. We did know about the existence of these localized magnetic anomalies—very small magnetic fields unlike the Earth that has a global magnetic field with an intensity of around 40,000 nanotesla. In contrast, those on the moon are a few hundered nanotesla.
But nobody thought that these small magnetic fields would obstruct the flow of plasma on the lunar surface. We showed for the first time that the moon too could generate a mini-magnetic field, which we termed as a mini-magnetosphere of the size of a few hundred kilometres (smallest in our solar system).You can use these experiments or techniques for any other planetary body sans an atmosphere—asteroids, mercury, or even exo-planets (outside our solar system).
You have also made very significant contributions to detection and delineation of the nature and origin of planetary X-rays.
We were looking for X-ray emissions from big planets like Jupiter, Saturn, etc. We found that these giant planets are reflecting a significant amount of X-rays from the Sun. Using Nasa’s Chandra X-ray Observatory and XMM-Newton, we found that the planets were also showing up signatures, which suggested that there were things happening on the other side of the Sun, which we were not able to see from the Earth. This became very exciting for Nasa too, because now we could use these planets as giant mirrors in the sky. I showed them when the angle between the Sun, Earth and the planets like Jupiter or Saturn is more than 60 degrees or so, the planets would be looking at the hemisphere of the Sun which is not visible to the Earth. And if you can see the signature of the flare on the other hemisphere, you can know what is happening there with no information coming directly to the Earth. This is what became an eye-catcher for Nasa, and they issued a press release (go.nasa.gov/2jvb9La) about this development.
Given that the universe is so old and vast, do you believe in the existence of extraterrestrial life?
My view is that life may exist outside Earth. If you see, there are billions of galaxies. How can Earth be so unique that it is the only planet to bear life? The question now is, whether we will see life that is similar to that on Earth. Or will we see life in a different form, and will be able to even recognize such life forms. Life could exist in our solar system or even outside it. But the distances are so large that communication becomes very difficult even if the species is intelligent.
Do you believe in God?
I don’t mix science and God. I do believe in God as a means to achieving mental peace and solace.
What do you plan to do with the Infosys prize money?
(Laughs) I have not even thought about that.
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