spaceplasma:

Helioseismology: seismology of the Sun

The Sun oscillates and vibrates at many frequencies, like an ocean surface or …like a bell. Certain frequencies are amplified by constructive interference(wave propagation) and the turbulence “rings” the sun like a bell. Unfortunately, sound does not carry through the vacuum between the Sun and the earth, so we have to “listen" to the oscillations by looking at the motions of material on the surface of the Sun. With the right instruments, scientists can "hear" this ringing or pulsations from the Sun. To do this, they use an instrument called a Michelson Doppler Imager (MDI), mounted on the SOHO spacecraft and the Helioseismic and Magnetic Imager (HMI), one of the three instruments that make up the Solar Dynamics Observatory (SDO).

Although direct study of its interior is impossible —mostly because the Sun is nearly opaque to electromagnetic energy, insights into the conditions within the Sun may be gained by observing oscillating waves, rhythmic inward and outward motions of its visible surface. These oscillations on the surface are due to sound waves generated and trapped inside the sun. Sound waves are produced by pressure fluctuations in the turbulent convective motions of the sun’s interior. These trapped sound waves set the sun vibrating in millions of different patterns or modes. Using this acoustic energy, we can “see into the Sun”, just as geologists use seismic waves to study the structure of the Earth, the discipline of helioseismology makes use of acoustic pressure waves (infrasound) traversing the Sun’s interior. These oscillations are seen as volumes of gas called granules near the Sun’s surface that rise and fall with a particular frequency. It is like seeing the rolling motions of convection cells on the surface of  boiling water. This happens very close to the surface where the flow of energy that started in the nuclear reactions in the core reaches the surface and suddenly escapes. The sound from the convection is then trapped and filtered inside the sun to produce the solar music

Helioseismologists can use the properties of these waves to determine the temperature, density, composition, and motion of the interior of the sun. The spectral lines emitted from gas moving upwards will be slightly Doppler-shifted to the blue; spectral lines from gas moving downwards will be slightly Doppler-shifted to the red. In this way the rolling motions of convection near the Sun’s surface can be mapped out. There are three types of oscillations. Pressure modes (p-modes) are sound waves trapped in the temperature gradient (like an echo bouncing around inside a cavern). Fundamental modes (f-modes) or surface gravity waves are caused by gravitational interactions with the sun’s surface and resemble ocean waves. Gravity modes (g-modes) are not completely understood, but they are believed to be the result of buoyancy effects. All the known pressure and fundamental modes (some 10 million) have oscillation periods of less than 18 minutes, and most are around 5 minutes. The gravity modes are not known conclusively to exist, but they are predicted to have periods of 40 minutes or longer (160-min).

Further readings:

(via paradoxicalparadigms)

sagansense:

ageofdestruction:

alanis: Clouds and shadows on Mars, photographed by Mars Express, 24th May 2012.

Between 28 and 36°S, 284°E, on the arc of highlands that surround the southeast Solis Planum. The crater split between the 2nd and 3rd images is Voeykov, about 75 km across, named for climatologist and geographer Alexander Ivanovich Voeykov (1842-1916). The small, deep crater toward bottom left of the 4th image is Los, named for a village of about 400 people in Gävleborg County, Sweden.

Composite of 3 visible light images for colour, and 5 monochrome images for animation. Colour is not balanced naturalistically, and the slightly psychedelic colours of the clouds are a result of mismatches between the images where the clouds have moved between exposures.

Image credit: ESA. Composite: AgeOfDestruction.

You’re looking at another world. Let that sink in. We will be livestreaming in real time soon…

(via distant-traveller)

nemfrog:

Lunar mountains photographed. 1884.

nemfrog:

Lunar mountains photographed. 1884.

(via starstuffblog)

ohstarstuff:

The photos Cassini has been sending back go beyond science. They are art.
In this image, Titan can be seen behind Saturn’s rings with Enceladus peaking onto the crescent. The bright surrounding ring is atmospheric haze above Titan, gas that is scattering sunlight to a camera operating onboard the robotic Cassini spacecraft. Since the image was taken pointing nearly at the Sun, the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn appear similar to a photographic negative.
(Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA)

ohstarstuff:

The photos Cassini has been sending back go beyond science. They are art.

In this image, Titan can be seen behind Saturn’s rings with Enceladus peaking onto the crescent. The bright surrounding ring is atmospheric haze above Titan, gas that is scattering sunlight to a camera operating onboard the robotic Cassini spacecraft. Since the image was taken pointing nearly at the Sun, the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn appear similar to a photographic negative.

(Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA)

(via starstuffblog)

balnibarbi:

Prisma 633 by Boy de Haas http://flic.kr/p/hLVhWc

balnibarbi:

Prisma 633 by Boy de Haas http://flic.kr/p/hLVhWc

(via lesbianhorse)

inspirewiki:

Leaving Earth.
Eight years ago, on its way toward the planet Mercury, the MESSENGER spacecraft swung past Earth, giving us a beautiful time-lapse video of what it looks like to leave Earth far into the distance.
Video credit: NASA

inspirewiki:

Leaving Earth.

Eight years ago, on its way toward the planet Mercury, the MESSENGER spacecraft swung past Earth, giving us a beautiful time-lapse video of what it looks like to leave Earth far into the distance.

Video credit: NASA

(via starstuffblog)

space-pics:

Took this picture of the super moon with my telescope (more in comments)http://space-pics.tumblr.com/

space-pics:

Took this picture of the super moon with my telescope (more in comments)
http://space-pics.tumblr.com/

bibidebabideboo:

1st Astronauts Belka Strelka Space Dogs Rocket Shtof JUG Porcelain Gzhel (eBayから)

(via jump-suit)

nemfrog:

Plate VI. Lunar Craters. Copernicus. 1889.

nemfrog:

Plate VI. Lunar Craters. Copernicus. 1889.

(via starstuffblog)

Launching February 2nd 2013
Sketchbook and notes from a Dark Sky Public Art project creating shelter, sonics and a way for star gazers in Galloway Forest, Scotland. The forest is unique in having zero light pollution, there is only one other dark sky park in Europe. Therefore the views of the night sky are remarkable.

There were five traditional stone bothy shelters in the park, our work is at White Laggan bothy in the interior of the forest by Loch Dee.

We made thermal Spacesuits to combat elements and Sky gazers which are angled for observing. We have also made a vinyl LP of space ballads. The space suits are free for public use.

Our project url is
http://www.yird-muin-starn.com
Our process url is
http://www.kaffematthews.net/Yird_Muin_Starn

Yird Muin Starn (Old Scots for Earth Moon Stars) is by Mandy McIntosh and Kaffe Matthews.

Supported by Creative Scotland through the Vital Spark award scheme.

Further details of Mandy McIntosh's work can be found at www.ham-and-enos.org.uk

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