Moon Pi and Mountain Shadow
14.03.2024

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude.

The Colorful Clouds of Rho Ophiuchi
12.03.1996

The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light.

Cassini Spacecraft Crosses Saturns Ring Plane
23.02.2014

If this is Saturn, where are the rings? When Saturn's "appendages" disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn's unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear.

APOD: 2023 January 24 Б LHS 475 b: Earth Sized Exoplanet
24.01.2023

If you could stand on exoplanet LHS 475 b, what might you see? No one knows for sure but pictured here is an interesting guess made by an Earth-based artificial intelligence (AI) engine.

Jones Emberson 1
24.02.2023

Planetary nebula Jones-Emberson 1 is the death shroud of a dying Sun-like star. It lies some 1,600 light-years from Earth toward the sharp-eyed constellation Lynx. About 4 light-years across, the expanding remnant...

Solar Eclipse and SOHO
31.03.2006

Neither rain, nor snow, nor dark of night can keep the space-based SOlar Heliospheric Observatory (SOHO) from watching the Sun. In fact, from its vantage point 150 million kilometers sunward of planet Earth, SOHO's cameras can always monitor the Sun's outer atmosphere, or corona.

A Laser Strike at the Galactic Center
6.01.2019

Why are these people shooting a powerful laser into the center of our Galaxy? Fortunately, this is not meant to be the first step in a Galactic war. Rather, astronomers at the Very Large Telescope (VLT) site in Chile are trying to measure the distortions of Earth's ever changing atmosphere.

Just Another Day on Aerosol Earth
18.04.2020

It was just another day on aerosol Earth. For August 23, 2018, the identification and distribution of aerosols in the Earth's atmosphere is shown in this dramatic, planet-wide digital visualization. Produced in real...

The Shadow of Ingenuity s Damaged Rotor Blade
10.02.2024

On January 18, 2024, during its 72nd flight in the thin Martian atmosphere, autonomous Mars Helicopter Ingenuity rose to an altitude of 12 meters (40 feet) and hovered for 4.5 seconds above the Red Planet. Ingenuity's 72nd landing was a rough one though.

APOD: 2024 February 25 Б A Phoenix Aurora over Iceland
25.02.2024

All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet September night, much of that night's auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again.