Astronomy Picture of the Day

2011-10-01

Though the sizes are not to scale, the Sun and planets of the inner solar system are shown in this illustration, where each red dot represents an asteroid. New results from NEOWISE, the infrared asteroid hunting portion of the WISE mission, are ...

2011-09-30 Fredrick Broms

On September 26, a large solar coronal mass ejection smacked into planet Earth's magnetosphere producing a severe geomagnetic storm and wide spread auroras. Captured here near local midnight from Kval?ya island outside Troms? in northern Norway, ...

2011-09-29 Tony Hallas

In this crowded starfield spanning some 3 degrees within the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula. A compact star forming region, the cosmic Cocoon punctuates a long trail of obscuring interstellar dust clouds. ...

2011-09-28

One of the most active sunspot groups in years is currently crossing the Sun. AR 1302 first came around the Sun's edge last week and is so large it can be seen without a telescope. Coronal Mass Ejections from AR 1302 have already caused strong ...

2011-09-27

Have you ever dreamed of flying high above the Earth? Astronauts visiting the International Space Station do this every day, circling our restless planet twice every three hours. A dramatic example of their view was compiled in the above ...

2011-09-26

Part of Mars is defrosting. Around the South Pole of Mars, toward the end of every Martian summer, the warm weather causes a section of the vast carbon-dioxide ice cap to evaporate. Pits begin to appear and expand where the carbon dioxide dry ...

2011-09-25

Tsunamis this large don't happen on Earth. During 2006, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun. Pictured above, the tsunami wave was captured moving out from ...

2011-09-24 Tunç Tezel

From Sagittarius to Carina, the Milky Way Galaxy shines in this dark night sky above planet Earth's lush island paradise of Mangaia. Familiar to denizens of the southern hemisphere, the gorgeous skyscape includes the bulging galactic center at ...

2011-09-23 Yuichi Takasaka

September's equinox arrives today at 0905 UT. As the Sun crosses the celestial equator heading south, spring begins in the southern hemisphere and autumn in the north. And though the seasonal connection is still puzzling, both spring and autumn ...

2011-09-22

Linking spiral arms, two large colliding galaxies are featured in this remarkable cosmic portrait constructed using image data from the Hubble Legacy Archive. Recorded in astronomer Halton Arp's Atlas of Peculiar Galaxies as Arp 272, the pair is ...