X-ray Transit of Mercury
2.07.1998

This sequence of false color X-ray images captures a rare event - the passage or transit of planet Mercury in front of the Sun. Mercury's small disk is silhouetted against the bright background of X-rays from the hot Solar Corona.

APOD: 2023 July 30 Б Spiral Aurora over Icelandic Divide
30.07.2023

Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of a great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background.

Aurora over Icelandic Fault
30.08.2016

Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization.

X ray Transit of Mercury
6.11.1999

This sequence of false color X-ray images captures a rare event - the passage or transit of planet Mercury in front of the Sun. Mercury's small disk is silhouetted against the bright background of X-rays from the hot Solar Corona.

Active Region 1002 on an Unusually Quiet Sun
24.09.2008

Why has the Sun been so quiet recently? No one is sure. Our Sun has shown few active regions -- that house even fewer associated sunspots -- for over a year now, and such a period of relative calm is quite unusual.

Spiral Aurora over Icelandic Divide
21.04.2019

Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization.

Aurora over Maine
17.09.2014

It has been a good week for auroras. Earlier this month active sunspot region 2158 rotated into view and unleashed a series of flares and plasma ejections into the Solar System during its journey across the Sun's disk.

Maximum Sun
1.03.2001

Astronomers recently witnessed an astounding, large scale solar event as the Sun's north and south magnetic poles changed places! But, this complete solar magnetic field flip was actually anticipated. It occurs every 11 years during the maximum of the solar activity cycle.

X Class Flare
17.02.2011

On Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare. The blast was the largest so far in the new solar cycle. Erupting from active region AR1158...

A Filament Leaps from the Sun
8.11.2021

Why, sometimes, does part of the Sun's atmosphere leap into space? The reason lies in changing magnetic fields that thread through the Sun's surface. Regions of strong surface magnetism, known as active regions, are usually marked by dark sunspots.