On Thursday NASA announced that its shiny new James Webb Space Telescope had directly imaged a world beyond our solar system for the first time and exceeded expectations in doing so.
Webb’s capabilities offer the promise of being able to not just count and catalog exoplanets but perhaps for the first time peeking under the covers of distant atmospheres to check for hints of life.
Astronomers have only been able to confirm the existence of planets circling other stars light years away from us since the 1990s at the earliest. For the most part we have not had a very good look at any of these thousands of planets discovered over the past three decades.
Before Webb, most exoplanet observations were conducted through one of two methods – watching a star for brief dips in brightness that indicate a planet passing in front of it, or slight wobbles in the star that can be caused by a planet’s gravity influencing it ever so slightly.
In other words, we’ve rarely ever looked directly at an exoplanet, we’ve really just been observing their secondary effects on host stars. We just simply haven’t had instruments powerful enough to directly detect the light from far-off worlds.
A new generation of massive telescopes being built on the surface of Earth promise to peer farther into the cosmos and at smaller targets like exoplanets for the first time. And NASA’s Webb telescope has also long been anticipated for its potential to observe them in more detail.
In the past few weeks it’s started to look as though Webb could exceed expectations.
First came the news last month that Webb had managed to pick up carbon dioxide in the atmosphere of the gas giant planet WASP-39b. That was done using spectroscopy that analyzes light from the host star shining through the planet’s atmosphere.
Now Webb has taken a direct look at another Jupiter-like giant planet around 385 light years away, this one called HIP 65426 b.
The remarkable images of the planet are comparable to how we think of taking a photo of it directly, as opposed to the other aforementioned techniques akin to looking for a planet’s shadow rather than the planet itself.
Naturally, looking directly at any object rather than watching its shadow provides far more detail about what is going on with the object. In the case of an exoplanet, a direct image is particularly promising in looking for signs of alien life.
No one is expecting gas giant planet HIP 65426 b to be a likely candidate for hosting life as we know it, but scientists are hopeful that Webb and other upcoming instruments may be able to directly image smaller and more Earth-like planets.
Of course, if Webb were ever to point at a planet and see signs of alien megastructures reminiscent of the Death Star or an armada of advanced spacecraft, we’ll have some serious discussions to have as a species.
So in a way you might also consider the new space observatory a sort of early warning system.