You entered: helium
3.07.1996
Why is there a hole in the center of this nebula? A leading explanation is that it is caused by the stellar winds from the stars that live there. Stars - including the Sun - expel electrons, protons, and other charged ions in a steady stream - the stellar wind.
Eruptive Prominence
8.07.1999
Activity on our parent star continues to increase as the sun approaches a maximum in its 11-year solar cycle, expected in the year 2000. On June 14 - only a week before the solstice - the space-based SOHO observatory recorded this stunning view of an immense prominence erupting from the sun's southern latitudes (south is up).
Escape From The Sun
19.11.1997
Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb. On September 14, this...
A Solar Prominence Unfurls
4.10.2008
On September 29, this magnificent eruptive solar prominence lifted away from the Sun's surface, unfurling into space over the course of several hours. Suspended in twisted magnetic fields, the hot plasma structure is many times the size of planet Earth and was captured in this view by the Sun-watching STEREO (Ahead) spacecraft.
A Solar Prominence Erupts
24.09.2001
Our Sun is still very active. Last year, our Sun went though Solar Maximum, the time in its 11-year cycle where the most sunspots and explosive activities occur. Sunspots, the Solar Cycle, and solar prominences are all caused by the Sun's changing magnetic field.
Two Hours Before Neptune
22.09.2002
Two hours before closest approach to Neptune in 1989, the Voyager 2 robot spacecraft snapped this picture. Clearly visible for the first time were long light-colored cirrus-type clouds floating high in Neptune's atmosphere. Shadows of these clouds can even be seen on lower cloud decks.
Southern Saturn from Cassini
18.10.2004
What happens to Saturn's pervasive clouds at its South Pole? Visible in the above image of Saturn are bright bands, dark belts and a dark spot right over the South Pole. The above...
A Storm on Saturn
17.10.1995
The white wisp shown on Saturn's cloud tops is actually a major storm system only discovered in December of 1994. Saturn's clouds are composed of primarily hydrogen and helium, but the storm's white clouds are actually ammonia ice crystals that have frozen upon upheaval to the top of the atmosphere.
Uranus: The Tilted Planet
26.08.2001
Uranus is the third largest planet in our Solar System after Jupiter and Saturn. Uranus is composed mostly of rock and ices, but with a thick hydrogen and helium atmosphere. The blue hue of Uranus' atmosphere arises from the small amount of methane which preferentially absorbs red light.
Two Hours Before Neptune
8.08.2010
Two hours before closest approach to Neptune in 1989, the Voyager 2 robot spacecraft snapped this picture. Clearly visible for the first time were long light-colored cirrus-type clouds floating high in Neptune's atmosphere. Shadows of these clouds can even be seen on lower cloud decks.
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