Hubble Floats Free
6.03.1997

Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and upgrade it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere.

M33: Triangulum Galaxy
3.12.2010

The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way.

NGC 602 and Beyond
2.04.2017

Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust...

Equinox on Planet Earth
20.03.2019

Welcome to an equinox on planet Earth. Today is the first day of spring in our fair planet's northern hemisphere, fall in the southern hemisphere, with day and night nearly equal around the globe.

Comet Bradfield Passes the Sun
19.04.2004

Right now, Comet Bradfield is passing the Sun. The above image, the latest taken in the direction of the Sun by the SOHO LASCO instrument, shows the comet and its dust tail as the elongated white streak. The Sun would normally be seen in the very center but has been blocked from view.

NGC 4449: Close up of a Small Galaxy
25.02.2011

Grand spiral galaxies often seem to get all the glory. Their young, blue star clusters and pink star forming regions along sweeping spiral arms are guaranteed to attract attention. But small irregular galaxies form stars too, like NGC 4449, about 12 million light-years distant.

Looking Back at an Eclipsed Earth
30.05.2012

What's that dark spot on planet Earth? It's the shadow of the Moon. The above image of Earth was taken last week by MTSAT during an annular eclipse of the Sun. The dark spot appears quite unusual as clouds are white and the oceans are blue in this color corrected image.

APOD: 2024 May 11 Б AR 3664: Giant Sunspot Group
11.05.2024

Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 3664 is not only big -- it's violent, throwing off clouds of particles into the Solar System. Some of these CMEs are already impacting the Earth, and others might follow.

Full Moon Silhouettes
7.09.2014

Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged in early 2013 over Mount Victoria Lookout in Wellington, New Zealand.

Equinox on a Spinning Earth
19.03.2017

When does the line between day and night become vertical? Tomorrow. Tomorrow 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.