This week marks the launch of a new NASA space observatory on a grand mission to map over 450 million galaxies.
By mapping the entire sky four times over the course of two years, the SPHEREx mission (short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) will give scientists an opportunity to investigate the formation and evolution of galaxies and provide a window into the origins of the universe.
“It will provide an answer to a basic question: How did we end up here?” In a recent news briefing, Shawn Domagal-Goldman, acting director of the astrophysics division at NASA headquarters, stated.
A few hours prior to the planned departure window on Saturday, the launch from California’s Vandenberg Space Force Base was halted and rescheduled. In an update Sunday evening, NASA stated that the next window will not begin before 11:10 p.m. ET on Monday.
“The additional time will allow teams to continue rocket checkouts ahead of liftoff,” NASA stated.
Originally slated for February 27, liftoff was postponed many times by NASA, first to “finish vehicle processing and prelaunch checkouts,” and then due to availability at the launch site in California.
The cone-shaped spacecraft will launch on a SpaceX Falcon 9 rocket, joining four suitcase-sized satellites that NASA will simultaneously deploy on a different mission to study the sun.
According to NASA, the $488 million SPHEREx mission, which has been in development for roughly ten years, will map the celestial sky in 102 infrared colors, more than any previous mission.
In order to glimpse some of the earliest stars and galaxies in the universe that would otherwise be hidden from view, infrared equipment in space are perfect for penetrating through gas and dust. (People cannot see colors in the infrared spectrum because infrared light has longer wavelengths than the human eye can perceive.)
Similar to how sunlight splits into a rainbow of visible hues when it hits a prism, scientists may use a technique called spectroscopy to separate the infrared light from stars and galaxies into distinct colors. The spectra of an object can provide a wealth of information on its composition, density, temperature, and motion.
Jamie Bock, a physics professor at the California Institute of Technology and the SPHEREx mission’s principal investigator, stated that the observatory will use its spectrometers to measure these properties in hundreds of millions of galaxies and conduct a three-dimensional sky survey.
In addition to allowing the observatory to look into the genesis of water and other biological components in our Milky Way galaxy, Bock said these findings may provide answers regarding the birth of galaxies.
“We can use that to build up that three-dimensional map and to determine the distance to galaxies by splitting up the light, and we can also see the fingerprints of water,” Bock explained.
In addition to helping scientists understand how life emerged on Earth, tracing the origins of water may also provide hints about potential locations for essential components of life elsewhere in our galaxy.
“This is a new capability, and there is always the possibility of surprises and discoveries with new capabilities,” Bock stated.
One of astronomy’s most persistent riddles will be addressed by the SPHEREx mission as it charts the cosmic sky: what transpired in the initial seconds following the Big Bang, which formed the universe some 13.8 billion years ago?
According to one scenario, which was put forth in the late 1970s and early 1980s, the cosmos saw an astounding expansion of trillions of times in the initial fractions of a second following the Big Bang. The flat geometry and lack of curvature of the cosmos have been explained by the cosmic inflation theory, which has also been proposed as a potential explanation for the formation of some of the universe’s greatest structures, such as galaxies and clusters of galaxies.
However, the question of what caused cosmic inflation and why it occurred in the first place has long been a puzzle to astronomers. Since figuring out the exact distribution of hundreds of millions of galaxies will help scientists focus on the mechanics of cosmic inflation and how such a rapid expansion may have occurred, the SPHEREx mission might test the hypothesis in new ways.
According to Brock, “SPHEREx will trace out in three dimensions hundreds of millions of galaxies over the entire sky, testing certain models of inflation.”
According to Domagal-Goldman, the SPHEREx mission’s research on galaxies, cosmic inflation, and the universe’s beginnings could improve our knowledge of basic physics.
“In the lengthy history of human existence on this planet, we are extremely fortunate to be living at a time when we can truly provide answers to questions about the universe,” he remarked.