NASA will soon be launching a new space telescope with an epic mission: to observe millions of stars in over one hundred wavelengths. The SPHEREx mission will map the entire sky in the infrared wavelength to understand the history of the universe itself — and it may even clarify the origin of some of the building blocks of life itself.
As an astrophysics mission, the aim of SPHEREx (or the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) is to take large-scale images of the sky, observing hundreds of millions of stars and galaxies and using a technique called spectroscopy to split the incoming light into individual colors.
The mission will observe a total of 102 colors, though these are in the infrared range so they are beyond what is visible to the human eye. By looking in this range, which is similar to the wavelengths used by other telescopes like James Webb, scientists can learn about the position and movements of many distant objects. Furthermore, it helps researchers to identify where water and carbon dioxide are present, as the molecules distinctively block certain wavelengths of light.
While telescopes like Webb or Hubble look at individual objects in great detail, SPHEREx will look at the big picture, observing huge chunks of the entire sky.
“We are the first mission to look at the whole sky in so many colors,” said SPHEREx Principal Investigator Jamie Bock of NASA’s Jet Propulsion Laboratory and Caltech. “Whenever astronomers look at the sky in a new way, we can expect discoveries.”
The importance of water
How might all of this data collected by SPHEREx teach us about life? Well, that’s all a matter of following the water, because as far as we know, water is a key ingredient for life, along with others like carbon dioxide and carbon monoxide.
SPHEREx will track how and where these ingredients are found. The clouds of dust and gas which float in space are homes for frozen molecules of water and other compounds. As planets and stars slowly form from these clouds, the water and other ingredients become a part of the planets, creating the conditions in which life could develop.
Scientists are still learning about where water in planetary systems comes from, as previous research from the Submillimeter Wave Astronomy Satellite (SWAS) mission found that these interstellar clouds, called molecular clouds, contained less gaseous water than expected.
“This puzzled us for a while,” said SPHEREx scientist Gary Melnick of the Center for Astrophysics, Harvard & Smithsonian. “We eventually realized that SWAS had detected gaseous water in thin layers near the surface of molecular clouds, suggesting that there might be a lot more water inside the clouds, locked up as ice.”
Now, SPHEREx will be able to study these molecular clouds to see how deep ice forms using a technique called absorption spectroscopy. The mission will reveal how much ice is present in a given molecular cloud, giving scientists more information about how life’s most essential ingredient of water moves through the universe.
Telescopes working together
Many people think of telescopes being powerful when they can see very distant objects. And that is true — one measure of how useful or powerful a telescope is, is whether it can see very far-off objects in detail. But another measure is how much of the sky a telescope can see at one time.
To do science, researchers want both these highly targeted telescopes, like James Webb, and telescopes with a broad view of the sky, like SPHEREx. Then the two can work together for the best view of an intriguing object.
“If SPHEREx discovers a particularly intriguing location, Webb can study that target with higher spectral resolving power and in wavelengths that SPHEREx cannot detect,” explained Melnick. “These two telescopes could form a highly effective partnership.”
As well as working with other telescopes and tracking ingredients for life, information from SPHEREx will also aim to study how the universe behaved in the microseconds immediately following the Big Bang, called inflation. The telescope will study how galaxies are distributed today to track them backwards to see how and where they would have started out, giving information on this dramatic period where the universe increased in size by a trillion times.
SPHEREx is scheduled to launch no earlier than Tuesday, March 4 from Vandenberg Space Force Base in California, using a SpaceX Falcon 9 rocket to carry it to its sun-synchronous low-Earth orbit. It will perform a two-year mission surveying the entire sky.
