Unusual Spherules on Mars
10.02.2004

What are those unusual spherules on Mars? The Mars Opportunity rover has now photographed several unusual nodules on Mars that have a nearly spherical shape. Many times these spherules are embedded in larger rock outcroppings but appear grayer.

APOD: 2026 June 30 Б Unusually Smooth Sections of Asteroid Itokawa
30.06.2026

Why are parts of this asteroid's surface so smooth? The answer seems likely to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock.

Unusual Auroras Over Saturns North Pole
19.11.2008

What's causing this unusual aurora over Saturn? No one is sure. Infrared images by the robotic Cassini spacecraft of the north pole of Saturn have uncovered aurora unlike any other seen previously in our Solar System.

The Unusual Boulder at Tychos Peak
7.05.2018

Why is there a large boulder near the center of Tycho's peak? Tycho crater on the Moon is one of the easiest features to see, visible even to the unaided eye (inset, lower right). But at the center of Tycho (inset, upper left) is a something unusual -- a 120-meter boulder.

Jets from Unusual Galaxy Centaurus A
31.05.2011

Jets of streaming plasma expelled by the central black hole of a massive spiral galaxy light up this composite image of Centaurus A. The jets emanating from Cen A are over a million light years long. Exactly how the central black hole expels infalling matter is still unknown.

Unusual Mountain Ahuna Mons on Asteroid Ceres
9.10.2017

What created this unusual mountain? Ahuna Mons is the largest mountain on the largest known asteroid in our Solar System, Ceres, which orbits our Sun in the main asteroid belt between Mars and Jupiter. Ahuna Mons, though, is like nothing that humanity has ever seen before.

Unusual Red Glow Over Minnesota
17.02.2009

What in heaven's blazes is that? When landing in Minneapolis, Minnesota, USA in 2002, just after his flight descended below cloud level in the early evening, passenger Tyler Blessing saw and photographed "huge...

APOD: 2020 August 14 Б NGC 5189: An Unusually Complex Planetary Nebula
14.08.2020

Why is this nebula so complex? When a star like our Sun is dying, it will cast off its outer layers, usually into a simple overall shape. Sometimes this shape is a sphere, sometimes a double lobe, and sometimes a ring or a helix.

Unusual Dusty Galaxy NGC 7049
8.04.2009

How was this unusual looking galaxy created? No one is sure, especially since spiral galaxy NGC 7049 looks so strange. NGC 7049's strikingly appearance is primarily due to an unusually prominent dust ring seen mostly in silhouette. The opaque ring is much darker than the din of millions of bright stars glowing behind it.

An Unusually Smooth Surface on Saturns Calypso
17.02.2010

Why is this moon of Saturn so smooth? This past weekend, humanity's Saturn-orbiting Cassini spacecraft passed as close to Saturn's small moon Calypso as it ever has, and imaged the small moon in unprecedented detail. Pictured above is an early return, raw, unprocessed image of the 20-km long irregularly shaped moon.