Worlds beyond ours
In 1600, Italian philosopher Giordano Bruno believed in a universe filled with countless planets that supported life. He was burned alive for holding such beliefs. As of June 2019, more than 4,000 planets orbiting other stars – so-called exoplanets – have been discovered in our milky way galaxy alone. The contrast between Bruno’s time and our own reflects the evolution of mankind towards exploring the unknown. One of the fascinating quests of current science is the search for intergalactic life. The worst that can happen to such scientists today is merely the rejection of scientific funding.
When we peek outside of our solar system, we encounter billions of other stars. Our scientific study indicates that each of the 300 billion stars in our galaxy has at least one planet orbiting them. Given the grandeur of the universe, which consists of billions of galaxies woven in the curved carpet of empty space, we are naturally compelled to question the uniqueness of humanity. Why should earth be the only planet hosting life? Or at least the form of life we see and understand on earth… The discoveries of new stars and exoplanets and the ones to come intrigue astronomers. We could only imagine how our Earth-centric perspective would be shaken up if we discover a planet supporting signs of life.
Finding life elsewhere with the earth-based instrumentation is an ambitious high-hanging fruit, which requires big telescopes (30-meters+) equipped with complex exoplanet-finding machines. At present, we astronomers are more focused on understanding how exoplanets form and evolve, what their atmospheres look like and what they are composed of. As seeing is believing, one of the techniques used to find exoplanets — the one I work with — is direct imaging, which translates into taking images of exoplanets using big telescopes (10-meters). Sounds straightforward at first. However, exoplanets are extremely dim, and they are roughly thousand to 10 billion times fainter than their stars. Moreover, the earth’s atmosphere creates turbulence — something that makes the stars twinkle, moves their images on the camera and blurs out the star-planet signal when observing exoplanets from ground.
Searching for an exoplanet in outer space through the earth’s atmosphere is like searching for a bacterium at the bottom of a swimming pool! Not only this, the huge structure of telescopes themselves vibrate due to the motors’ motion and wind. The bigger is the structure, the higher are the chances that the star-planet image will be shaky and blurred. Instead of getting a clear image, we get big blobs of light where starlight is spread all over our scientific detector, making it extremely hard to form a focused image, let alone resolve a planet from its star.
Though it may sound like an unachievable feat, we are already imaging Jupiter-type giant exoplanets at a great distance from their stars. What my research concerns is the improvement of current technologies to image smaller and closer-in exoplanets. Using these technologies, I undo the effects of Earth’s atmospheric turbulence on the screen in real-time – which involves stabilizing the starlight on the detector, efficiently suppressing it, minimizing the stellar residue and processing the images to increase the faint signal from exoplanets. These technological advancements are essential in completing the picture by addressing questions such as: Is the architecture of our solar system unique? Are there extrasolar systems similar to our solar system? Are earth-like planets common? How do planets form and evolve? Is there life on the exoplanets?
How would the picture – literally – look like in the far future? Spacecrafts carrying instrumentation capable of taking high-resolution pictures and examining the compositions of exoplanetary atmospheres directly from space? This sounds more like science fiction today, but undoubtedly many more exciting discoveries will rise to the surface in the next few centuries. And at that point, we will be in Bruno’s shoes…
I am Garima Singh and I am a post-doc affiliated with Dr. Pierre Baudoz at the Observatory of Paris in the Laboratory for Space Science and Astrophysical Instrumentation. The research work is funded by Marie Skłodowska-Curie Actions.
Text by Fernanda Haffner
Illustration by Laurene Gattuso