SPHEREx will survey hundreds of millions of galaxies, as well as search the Milky Way for water and organic molecules essentials for life as we know it.

a projection of the Earth's own longitude lines on the celestial sphere. This alignment is also called a conjunction. New moons are invisible unless the moon passes directly in front of the sun ...

When we observe the planets from Earth, we see them projected onto the celestial sphere, which is the apparent sphere of stars surrounding our planet. This projection creates an optical illusion ...

With Mercury joining the show, all seven of Earth’s celestial neighbors will be present at dusk this week. By Katrina Miller Astute skywatchers may have already seen the striking line of planets ...

Full moons occur when the moon is on the opposite side of Earth from the sun. Because we designate the time of actual full moon as being when the moon is 180 degrees around the celestial sphere ...

SO SPHEREX GOES UP AND INSTEAD OF LOOKING DOWN AT EARTH, IT LOOKS OUT AT SPACE. WE TAKE A THREE DIMENSIONAL MAP OF THE ENTIRE CELESTIAL SPHERE. OUR DETECTORS HAVE RAINBOW COLORED GLASSES IN FRONT ...

The $488 million observatory is set to launch at the end of this month on a two-year mission to map the entire celestial sky.

The only lunar eclipse visible in the U.S. in 2025 happens Thursday. Here's what to know about this celestial event and when to see it.