Perihelion to Aphelion
8.07.2021

Aphelion for 2021 occurred on July 5th. That's the point in Earth's elliptical orbit when it is farthest from the Sun. Of course, the distance from the Sun doesn't determine the seasons.

A Martian Halloween
31.10.2005

From sunset to sunrise, an unusually bright yellowish orb will hang in the sky this Halloween: Mars. Yesterday, Earth passed Mars as they orbited the Sun, bringing Mars closer than it will be for the next thirteen years. Tonight though, Mars will be nearly as bright as last night, a beacon of extraterrestrial spookiness.

Large Eruptive Prominence Imaged by STEREO
18.04.2010

What's happened to our Sun? Last week, it produced one of the most power eruptive prominences ever seen. Pictured above, the prominence erupted in only a few hours and was captured in movie form by NASA's twin Sun-orbiting STEREO satellites.

Double Eruptive Prominences
18.04.2003

Lofted over the Sun on looping magnetic fields, large solar prominences are composed of relatively cool, dense plasma. When seen against the brilliant solar disk they appear as dark filaments, but these enormous magnetic...

High Noon Analemma Over Azerbaijan
14.10.2013

Is the Sun always straight up at noontime? No. For example, the Sun never appears directly overhead from locations well north or south of the Earth's equator. Conversely, there is always a place on Earth where the Sun will appear at zenith at noon -- for example on the equator during an equinox.

A Prominent Solar Prominence from SOHO
30.03.2004

One of the most spectacular solar sights is a prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. Last month, NASA's Sun-orbiting SOHO spacecraft imaged an impressively large prominence hovering over the surface, pictured above.

3I/ATLAS Flyby
26.12.2025

Attention grabbing interstellar visitor 3I/ATLAS made its not-so-close flyby of our fair planet on December 19 at a distance of 1.8 astronomical units. That's about 900 light-seconds. This deep exposure captures the comet...

Analemma Over the Porch of Maidens
21.12.2008

If you took a picture of the Sun at the same time each day, would it remain in the same position? The answer is no, and the shape traced out by the Sun over the course of a year is called an analemma.

APOD: 2023 May 17 Б Sunspot with Light Bridge
17.05.2023

Why would a small part of the Sun appear slightly dark? Visible is a close-up picture of sunspots, depressions on the Sun's surface that are slightly cooler and less bright than the rest of the Sun. The Sun's complex magnetic field creates these cool regions by inhibiting hot material from entering the spots.

Kepler Discovers How Planets Move
13.09.1997

Johannes Kepler used simple mathematics to describe how planets move. Kepler was an assistant to the most accurate astronomical observer of the time, Tycho Brahe. Kepler was able to use Brahe's data...