Astronomy Picture of the Day |
APOD: 2000 January 10 - Brown Sun Bubbling
Explanation:
Our Sun may look like all soft and fluffy, but its not.
Our Sun is an extremely large ball of
bubbling hot gas, mostly
hydrogen gas.
The
above picture was taken in a
specific color of light emitted by hydrogen gas called
Hydrogen-alpha.
Granules cover the solar
photosphere surface like shag
carpet,
interrupted by bright regions containing dark
sunspots.
Visible at the left edge is a
solar prominence.
Our Sun glows because it is hot, but it is not on fire.
Fire is the rapid acquisition of oxygen,
and there is very little
oxygen on the Sun.
The energy source of our Sun is the nuclear
fusion of hydrogen into
helium deep within its core.
Astronomers are still working to understand,
however, why so few
neutrinos are
measured from the
Sun's core.
APOD: 1998 October 25 - A Sunspot Up Close
Explanation:
Sometimes, small regions of the Sun appear unusually dark.
Visible above is a close-up picture of a
sunspot, a depression on the Sun's face that is slightly cooler and less luminous than the rest of the
Sun. The Sun's complex
magnetic field creates this cool region
by inhibiting hot material from entering the
spot.
Sunspots can be larger than the Earth and
typically last for only a few days.
This high-resolution picture also shows clearly that the
Sun's face is a bubbling sea of separate cells of hot gas.
These cells are known as granules. A
solar granule is about 1000
kilometers across and lasts about 10 minutes. After that, many
granules end up exploding.
APOD: 1998 May 15 - TRACE and the Active Sun
Explanation:
This
dramatic high resolution picture
looking across the edge of the Sun
was taken April 24th by a telescope on board
the newly launched
Transition Region and Coronal Explorer (TRACE) satellite.
It shows graceful arcs of intensely hot gas
suspended in
powerful looping magnetic fields which
soar above a solar active region.
The colorized image was made in the extreme ultraviolet light
radiated by highly
ionized Iron atoms.
With a temperature of a mere 6,000
degrees Celsius,
the sun's surface is relatively cool and dark at these wavelengths,
but the million degree hot plasma loops glow strongly!
Such TRACE images follow the plasma and magnetic structures arising
from the surface of the sun as they merge with the tenuous, hot
solar Corona or outer atmosphere.
By operating the
TRACE instruments during the Sun's increasingly
active phase,
scientists hope to explore the connections between
complex
solar magnetic fields and
potentially hazardous solar eruptions.
Authors & editors:
Robert
Nemiroff
(MTU)
& Jerry Bonnell (USRA)
NASA Technical Rep.:
Jay Norris.
Specific rights apply.
A service of:
LHEA at
NASA/
GSFC
&
Michigan Tech. U.