Small Galaxy NGC 4449
3.05.2007

Grand spiral galaxies often seem to get all the glory. Their newly formed, bright, blue star clusters along beautiful, symmetric spiral arms are guaranteed to attract attention. But small irregular galaxies form stars too, like NGC 4449, located about 12 million light-years away.

Mercury from Passing BepiColombo
28.06.2022

Which part of the Moon is this? No part -- because this is the planet Mercury. Mercury's old surface is heavily cratered like that of Earth's Moon. Mercury, while only slightly larger than Luna, is much denser and more massive than any Solar System moon because it is made mostly of iron.

Under A Sunspot
8.11.2001

At the Sun's surface, sunspots are known to be dark, planet-sized regions of intense magnetic fields. But what lies below? Using observations from the Michelson Doppler Imager (MDI) instrument aboard the space-based SOHO observatory, astronomers have derived this premier picture of the flow of material just beneath a visible sunspot.

Solar Cycle 25 Begins
17.09.2020

The general trend of monthly sunspot data now confirms that the minimum of the approximately 11 year cycle of solar activity occurred in December 2019, marking the start of Solar Cycle 25. That quiet Sun, at minimum activity, appears on the right of this split hemispherical view.

Supernova Remnant: Cooking Elements In The LMC
9.05.1996

Massive stars cook elements in their cores through nuclear fusion. Starting with the light elements of hydrogen and helium, their central temperatures and pressures produce progressively heavier elements, carbon, oxygen, nitrogen, etc. up through iron.

Columbia Memorial Station
22.01.2004

After leaving its nest, the Spirit rover turned to captured this spectacular view over the Colombia Memorial Station and the floor of Gusev crater on the 16th sol of its visit to Mars. The sharp picture looks toward the northeast.

Metal on the Plains of Mars
31.07.2011

What has the Opportunity rover found on Mars? While traversing a vast empty plain in 2005 in Meridiani Planum, one of Earth's rolling robots on Mars found a surprise when visiting the location of its own metallic heat shield discarded last year during descent.

A Colourful Moon
11.11.2017

The Moon is normally seen in subtle shades of grey. But small, measurable color differences have been greatly exaggerated in this mosaic of high-resolution images captured near the Moon's full phase, to construct a multicolored, central moonscape.

The Orion Bullets
3.03.2019

Why are bullets of gas shooting out of the Orion Nebula? Nobody is yet sure. First discovered in 1983, each bullet is actually about the size of our Solar System, and moving at about 400 km/sec from a central source dubbed IRc2.

APOD: 2025 June 22 Б A Berry Bowl of Martian Spherules
22.06.2025

How were these unusual Martian spherules created? Thousands of unusual gray spherules made of iron and rock and dubbed blueberries were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars in 2004.