Aerospace

It’s Official: The Sun is A Sphere

From the STEREO website:

February 6, 2011: It’s official: The sun is a sphere.

On Feb. 6th, NASA’s twin STEREO probes moved into position on opposite sides of the sun, and they are now beaming back uninterrupted images of the entire star—front and back.

“For the first time ever, we can watch solar activity in its full 3-dimensional glory,” says Angelos Vourlidas, a member of the STEREO science team at the Naval Research Lab in Washington, DC.

“This is a big moment in solar physics,” says Vourlidas. “STEREO has revealed the sun as it really is–a sphere of hot plasma and intricately woven magnetic fields.”

Each STEREO probe photographs half of the star and beams the images to Earth. Researchers combine the two views to create a sphere. These aren’t just regular pictures, however. STEREO’s telescopes are tuned to four wavelengths of extreme ultraviolet radiation selected to trace key aspects of solar activity such as flares, tsunamis and magnetic filaments. Nothing escapes their attention.

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STEREO Spacecraft at Solar Opposition This Weekend

Why would that be significant? Well, it would allow for a full 4PI (360×360°) view of the sun. The animated movie of the sun on STEREO’s Website currently has a gap in the coverage of the sun. The spacecraft are in a heliocentric orbit drifting away from the Earth, one leading and one lagging. This diagram shows the current position of spacecraft A (ahead) and B (behind). The scale is in astronomical units, the average distance between the earth and sun.

Sun-monitoring instrumentation on spacecraft like SOHO and STEREO have gone a long way in discovering what makes the sun behave in mysterious ways. Also, the data coming back (when not intentionally distorted by the IPCC, the CRU or NASA’s James Hansen) can be used to chart the relationship between solar activity and global climate.

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NOTE: This is the second posting of this article (the original article posted June 16, 2010) because the actual opposition will take place this weekend on Sunday, February 6, 2011. I updated the position graphic for Ahead and Behind and added a NASA STEREO Teaser Video.

Solar Eclipse as Seen From SDO

sdo-transit.jpgAn Interesting eclipse occurred earlier this month when the moon passed between the Solar Dynamics Observatory and the Sun. This is the first recorded lunar/solar eclipse taken by SDO although earth/solar eclipses happen often. SDO is like the Hubble Space Telescope but is totally devoted to solar activity.

The image at the right shows the partially-eclipsed solar disk (courtesy NASA – click to enlarge). I also uploaded a close-up image in which the mountains along the lunar limb can be discerned against the solar disc. This demonstrates the excellent resolution of the instruments aboard SDO.

The following is taken from the SDO website where you can download and watch a Quicktime video of the eclipse.

This was a first for SDO and it was visually engaging too. On October 7, 2010, SDO observed its first lunar transit when the new Moon passed directly between the spacecraft (in its geosynchronous orbit) and the Sun. With SDO watching the Sun in a wavelength of extreme ultraviolet light, the dark Moon created a partial eclipse of the Sun.

These images, while unusual and cool to see, have practical value to the SDO science team. Karel Schrijver of Lockheed-Martin’s Solar and Astrophysics Lab explains: “The very sharp edge of the lunar limb allows us to measure the in-orbit characteristics of the telescope e.g., light diffraction on optics and filter support grids. Once these are characterized, we can use that information to correct our data for instrumental effects and sharpen up the images to even more detail.”

Fathers Day Flare

The new solar cycle antes up a massive CME for Fathers day. From SpaceWeather.com . . .

FATHER’S DAY BLAST: Consider it a Father’s Day gift … from the sun. This morning around 1 a.m. UT, magnetic fields on the sun’s eastern limb became unstable and erupted, producing one of the most spectacular explosions of the year. NASA’s Solar Dynamics Observatory recorded the action:

The explosion did not cause a solar flare (a flash of electromagnetic radiation) but it did hurl a massive cloud of magnetized plasma into space. Because of the blast site’s location on the eastern limb, the cloud will not hit Earth. There won’t be any geomagnetic storms or auroras.

STEREO Spacecraft Approaching Diametric Opposition

Why would that be significant? Well, it would allow for a full 4PI (360×360°) view of the sun. The animated movie of the sun on STEREO’s Website currently has a gap in the coverage of the sun. The spacecraft are in a heliocentric orbit drifting away from the Earth, one leading and one lagging. This diagram shows the current position of spacecraft A (ahead) and B (behind). The scale is in astronomical units, the average distance between the earth and sun.

Sun-monitoring instrumentation on spacecraft like SOHO and STEREO have gone a long way in discovering what makes the sun behave in mysterious ways. Also, the data coming back (when not intentionally distorted by the IPCC, the CRU or NASA’s James Hansen) can be used to chart the relationship between solar activity and global climate.

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