A Phoenix Aurora over Iceland
2.01.2021

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.

Milky Way Auroral Flower
17.10.2022

Could the stem of our Milky Way bloom into an auroral flower? No, not really, even though it may appear that way in todayБs featured all-sky image. On the left, the central plane of our home galaxy extends from the horizon past the middle of the sky.

Aurora and Light Pillars over Norway
7.02.2022

Which half of this sky is your favorite? On the left, the night sky is lit up by particles expelled from the Sun that later collided with Earth's upper atmosphere Б creating bright auroras.

Arches Across an Arctic Sky
12.01.2021

What are these two giant arches across the sky? Perhaps the more familiar one, on the left, is the central band of our Milky Way Galaxy. This grand disk of stars and nebulas here appears to encircle much of the southern sky.

Aurora over Clouds
29.05.2021

Auroras usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact the Earth's magnetosphere, from which charged particles spiral along the Earth's magnetic field to strike atoms and molecules high in the Earth's atmosphere.

In Green Company: Aurora over Norway
8.11.2020

Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.

APOD: 2023 January 22 Б In Green Company: Aurora over Norway
21.01.2023

Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.

Night on a Spooky Planet
29.10.2022

What spooky planet is this? Planet Earth of course, on a dark and stormy night in 2013 at Hverir, a geothermally active area along the volcanic landscape in northeastern Iceland. Triggered by solar activity, geomagnetic storms produced the auroral display in the starry night sky.

September Sunrise Shadows
23.09.2022

The defining astronomical moment for this September's equinox was on Friday, September 23, 2022 at 01:03 UTC, when the Sun crossed the celestial equator moving south in its yearly journey through planet Earth's sky.

Equinox on a Spinning Earth
21.09.2021

When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles.