What is Spectroscopy and How are NASA Scientists Using It to Study Exoplanets?


Studying exoplanets has been a point of fascination for decades, but only in recent years has it been proven to be just as useful to us as it is fascinating.  Because of this, advanced technology needs to be funded, developed, constructed, and utilized in order to allow such a complex process of exoplanet observation to be performed.  And, that’s where spectroscopy comes in, changing the way in which we’re able to record data on these fascinating celestial bodies.

What are Exoplanets?

An exoplanet refers to a planet outside of our own solar system – in other words, a planet that orbits around a star other than our sun.  Exoplanets are, unsurprisingly, very hard to spot from Earth, not only because of their distance, but also because of the brightness of the stars that they orbit, which produces a glare.

Hundreds of exoplanets have been observed, however, and in 2009, NASA launched Kepler, a spacecraft developed to seek these planets out.  Naturally, like the planets in our own solar system, exoplanets vary in size and temperature, and it is believed that at least many of them can support life.

How Exoplanets are Observed by NASA

Like we said, exoplanets are complicated celestial bodies to study because of their distance and because of glare.  But, the ICEE (Instrument for Carbon Evolution Experiments) Research Group has developed a solution.  After they joined NASA’s Ames Astrochemistry and Astrophysics Laboratory, ICEE has ben able to observe the infrared spectra of polcyclic aromatic hydrocarbons, to compare them to IR astronomical observations.  This has been used to observe data performed by the James Webb Telescope, which uses spectrometry to record data and images that are otherwise difficult to record.

Spectroscopy is simply the method of observing electromagnetic spectra resulting from the interaction between electromagnetic radiation and matter.  The James Webb telescope features a spectrograph based on infrared technology, dispersing light from a particular object into a spectrum of components that can each be recorded independently.  This allows us to gain information about properties like mass, temperature, and chemical composition – in this case, the properties of exoplanets that give us far more information about other solar systems and their celestial bodies, and how they compare to our own.

Spectroscopy is a key part of the future of space exploration, allowing us to uncover data that was never before observable.  The Kepler mission discovered exoplanets years ago, but now, with modern spectroscopy, we can begin to learn more about what makes each of these exoplanets unique.  The process relies on the exoplanet’s star as the source of light, and its atmosphere as a sample that allows scientists to collect data.  The actual telescope function allows the exoplanet to be detected in the first place.

Of course, using such instruments isn’t a simple feat.  For one thing, there’s the issue of size.  Naturally, it’s efficient to use as small of an instrument as possible, and that’s easier said than done given the special demands of such an advanced instrument.  Besides that, only recently has technology evolved so that communications between these instruments and computers was efficient enough to provide accurate data that was easy to read.

Before the use of the James Webb telescope to observe these exoplanets, we relied on a much more basic method, known as the transit method.  Essentially, basic observations could be made about an exoplanet’s size based on observing the dimming of a star’s light, which would indicate the planet completing an orbit by its full or partial blocking of its star.  However, this never offered perfect accuracy due to too many other variables, like the angle of the orbit, and its distance from the star it orbits.  The result was a number of “false positives,” which turned out to be disappointing and inconclusive.

Then came the radial velocity method, in which it was determined that if a star slightly wobbles, that implies that a planet is orbiting around it due to the gravitational pull between the two bodies.  This method has enabled the discovery of hundreds of exoplanets in recent years.  But, they could never be observed in a more in-depth way to uncover things like temperature and chemical composition.

Spectroscopy instruments used by NASA today allow for flawless accuracy, and the ability to go far beyond what we thought was possible in terms of recording data on these exoplanets and their properties. 

We’re About to Learn More About Exoplanets Than Ever Before

NASA’s ever-evolving technology has finally made it possible to gain clear insight into the nature of exoplanets once undiscovered not too long ago.  Thanks to spectroscopy, as seen on the James Webb telescope, uncovering secrets of these bodies can provide us with fascinating discoveries, as well as a better understanding of whether or not life exists outside of our own solar system.

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