- The European Southern Observatory recently announced the discovery of Proxima b, a planet that orbits a star (Proxima Centauri) that’s quite close to the solar system. Proxima Centauri is our sun’s nearest star neighbour.
- Distance isn’t the only reason why those on earth would want to check out Proxima b. The planet is believed to be rocky, with the right temperature to host water, and with the right size for life to thrive on. At the same time, scientists have been able to deduce that it is phase-locked with its star – that is, one side constantly faces its star – this and other factors such as its rotation lead them to believe that so it may have no seasons. To know how habitable it is, however, the planet needs to be probed further. Scientists plan to do just that – through what are called nanoprobes.
Here’s a Q&A about what it would take to probe Proxima b:
How far is Proxima b from earth, and what could be the best way to study it?
- It is only 4.2 light years away – in other words, light can travel this distance in 4.2 years. So, in principle, if we have some object, such as a small robot that can travel at the speed of light it would reach the star in just about 4.2 years, and we can study it just as we study Mars today. The only thing is in order to travel at the speed of light, an object has to be massless. So what one can aim for is to build a tiny robot that can travel at a good fraction of this speed.
- Are such robots available now?
- No, unfortunately. It’s still a technology for the future – perhaps a generation away. But what’s promising here is that people believe it can be done. The Breakthrough Starshot programme is all about this. As Pete Worden of the Breakthrough Foundation said in the press conference to announce the discovery of Proxima b, there is a plan to develop nanoprobes that can sail through space and tour the vicinity of the planet and come back loaded with pictures and memories.
- What is the Breakthrough Starshot programme?
- An ambitious plan, but in the words of Pete Worden the best we have now. It is a plan to send thousands of nanoprobes into space. These being small, can be accelerated to about 20 per cent the speed of light. That is, one-fifth the speed of light. Now, if light can travel the distance to Proxima b in about four years, something travelling at one-fifth the speed can reach there in a mere 20 years. This is entirely workable.
- By the way, the Starshot programme is a part of the Breakthrough Initiatives. This is an organisation founded by Yuri Milner, the Russian venture capitalist and physicist. On the board of Breakthrough Initiatives are, among others, Stephen Hawking and Mark Zuckerberg.
- What would nanoprobes involve?
- Imagine an integrated chip having among other necessities a camera and a battery in something weighing a gram or so. If you can then attach this to a light sail and a beamer, you would have a nanoprobe or nanocraft. Basically, it is a very tiny robot attached to a sail (which can control the direction of flight), which can be propelled to the high speeds required and which can also flyby Proxima b or any other target and shoot pictures and come back to tell us a story.
- Can we construct these nanoprobes and send them up in a few years?
- Not exactly! There are major challenges to be met in every step of the process. From miniaturizing probes to building powerful (gigawatt) lasers that can propel the objects far into space and guide them, from fabricating meta-materials for the sails to ensuring the protection of these probes as they travel at such high speeds through space, and much more.
- If we do manage to launch the nanoprobes, what can we expect?
- We can expect that these will shoot through space and reach Proxima b in twenty years from the time of launch, then take a flyby, shoot pictures that will tell us what the planet looks like and whether life can survive there, whether there are life forms there, and much more. They will come back in another twenty years with the pictures. So in a space of about forty years – one generation – we would possess knowledge of the star and its planet.