India and international science have a new sophisticated space-based telescope called Astrosat. The India Space Research Organization (ISRO) designed and built it. Launched on India’s Polar Satellite Launch Vehicle from the Satish Dhawan Space Centre, it is in its 640-kilometre-high orbit over the equator. Astrosat has new capabilities that can help us answer our most fundamental questions.
We are living in great times for telescopes. New space-based telescopes may lead to discoveries as revolutionary as those that followed on Galileo’s small earthbound telescopes 500 years ago.
Why is this investment happening? Is it because these instruments can find new physics at less cost than particle accelerators can? It’s true, they do. But far more fundamentally it is because they can reveal physics at the deepest level — the incredibly tiny Planck scale — that is far beyond the reach of any particle accelerator we can ever build.
Roughly speaking, the Planck scale is smaller than an atom in the same way that an atom is smaller than our solar system, only more so.
There’s no way we can ever see it. But the universe does things that touch the Planck scale all day, every day. It puts on amazing science shows out there for free and (some say) these shows offer us our best and maybe only windows into physics at a scale where space itself breaks down and is literally particular. Neither relativity nor quantum mechanics has anything to say about the Planck scale.
With the right equipment we can see those amazing shows in many “colours” A broad range of photon frequencies tells tales about the physics of strange cosmic objects. For example, huge black holes at galactic centres blast out vast beams of particles powered by energies far higher than we can ever achieve on Earth.
Like the human eye, a telescope tends to show a narrow band of photon frequencies. But now, with many telescopes in operation, there is a move afoot to study interesting objects using more than one of them.
For example, the European Space Organization team that recently found the first stars forming in the early universe used images from three different telescopes to decipher what was going on. Think of movies that have not only images but also sound (and now are in 3D). One gets far more information from two or three senses than from only one. It’s a kind of astronomic son et lumière.
This is where Astrosat adds a new level of space-telescope sophistication. Like the James Webb Space Telescope (JWST), which is expected to launch in 2018, it will search for signs of strange events far beyond our solar system. But its technology gives it a big advantage. ISRO says: “Astrosat will observe the universe in the optical, ultraviolet, low- and high-energy X-ray regions of the electromagnetic spectrum, whereas most other scientific satellites are capable of observing a narrow range of wavelength band.”
Astrosat’s five instruments span photon energies from two electron volts to 150,000 electron volts.
Some of the most interesting objects in the universe — such as black holes at the centres of galaxies — emit photons with energies across this range. So, when Astrosat researchers spot, let’s say, a burst of X-rays using one instrument, they can quickly turn to others to get more information.
ISRO’s project has another claim to fame: India built Astrosat for the equivalent of less than US$30 million. This is a striking achievement because cutting-edge space telescopes (Hubble and JWST) typically cost billions.
When astronomy gets so much less expensive, we can do more of it, and we all get to keep the change.
Colin Gillespie is a physicist and author whose most recent book is Time One: Discover How the Universe Began. He writes a weekly web blog Science Seen.
Republished from the Winnipeg Free Press print edition December 5, 2015 D4