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.
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.
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.
An 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.
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.”
Speaking of solar activity, a giant coronal hole opened up in the Sun’s northern hemisphere earlier this week, triggering auroras at high latitudes. Image made by the Solar Dynamics Observatory (SDO), via APOD. Click image to enlarge.
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.
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.
Solar activity has been increasing in recent months. This extraordinary video depicts a “plasma ring” coronal mass ejection (CME) as captured by SOHO. Watch the lower right corner for the ring ejection.
The Apollo-13 astronauts safely returned to Earth on April 17, 1970. Today commemorates the 41st anniversary of the dramatic conclusion to what must have been the most tedious and frightening events in space exploration history.
NASA launched Apollo-13 to be the third manned landing on the Moon. Two days into the mission, an oxygen tank on board the command module exploded, causing the end of the planned mission and initiated a dramatic space rescue effort, both back on Earth and on board the spacecraft.
The flight was commanded by James A. Lovell, with John L. “Jack” Swigert command module pilot, and Fred W. Haise lunar module pilot. The three astronauts and the Apollo-13 ground crew pieced together a rescue plan. Despite limited power, loss of cabin heat, shortage of potable water, and the critical need to jury-rig the carbon dioxide removal system, the crew returned safely to Earth on April 17, and the mission was termed a “successful failure”.
During the early 1990’s (I don’t remember the exact date), the Management Club at the company where I worked, invited Fred Haise to speak at one of our dinner meetings. He brought along a slide show and much anecdotal history of the Apollo-13 events. Haise recounted his time as an adviser to Bill Paxton, who played the role of Haise in the Apollo-13 film. Needless to say, the movie strayed from the business-like conduct of the astronauts in favor of dramatics, but the story line went more-or-less like the actual events, according to Haise.
After the presentation, I stepped to the podium (along with most everyone else there) and shook the hand of a real space hero.
Or should it be SUN-IMPACTOR COMET? I saw this yesterday on SpaceWeather.com:
SUNGRAZING COMET: Today, the sun had a comet for breakfast. The icy visitor from the outer solar system appeared with no warning on April 9th and plunged into the sun during the early hours of April 10th. One comet went in, none came out. The Solar and Heliospheric Observatory (SOHO) had a good view of the encounter.
The comet was probably a member of the Kreutz sungrazer family. Named after a 19th century German astronomer who studied them in detail, Kreutz sungrazers are fragments from the breakup of a giant comet at least 2000 years ago. Several of these fragments pass by the sun and disintegrate every day. Most are too small to see but occasionally a big fragment like today’s attracts attention.
This has been an active year for big, bright sungrazers. There was one on Jan. 4th, one on March 12th, and now one today. Normally we see no more than 3 or 4 bright ones in a whole year; now we’re seeing them almost once a month. It could be a statistical fluctuation or, maybe, a swarm of Kreutz fragments is nearing perihelion (closest approach to the sun). Stay tuned for doomed comets!
Before I retired, I had the opportunity to work on a lot of very interesting and exotic aerospace projects. I worked on projects involving everything from Intercontinental Ballistic Missile systems to Airborne Multimode Radar systems to Geosynchronous Communications Satellite systems. I developed electronics for Electro-optical systems such as Forward Looking Infrared imaging, Laser Rangefinders, Target Designators and Guidance. I developed software for Automated Test Equipment, Cockpit Simulators, Global Communications Satellites and more. Hell - I even was co-inventor on the Barbie Piano project when I briefly worked at Mattel Toys.
Fewer things make me more proud than when a project I worked on gets some press for making a milestone. Although I had more to do with the avionics equipment for the Joint Strike Fighter than the flight systems, it still gives me pride to see the first flight milestone. This is a magnificent aircraft with a host of exotic systems and capabilities. I could tell you about them, but then - well - you know . . .
