Posted on by Fraser Cain

Video of the Sun, Thanks STEREO

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Well, this is one of the coolest things I’ve seen all week. NASA released a new video of the Sun, captured by the twin STEREO spacecraft. The video, in Quicktime format, covers 2.5 days of the Sun, and shows it slowly rotating, with solar prominences blasting out into space.

If you want to just cut straight to the video, check it out here.

The series of images were captured by STEREO from August 16-18, 2007, and then stitched together into a single animation. The prominences that you see on the edges of the Sun were captured in extreme ultraviolet light by the Ahead spacecraft (the one leading the Earth in orbit). And if you watch right to the end, you’ll see a prominence on the upper side arch away into space.

Just amazing to watch.

Click here to watch the video.

Just in case you need a reminder, NASA’s STEREO mission is a set of twin solar observing spacecraft. One is leading the Earth in our orbit around the Sun, and the other is trailing behind us. Because of their different points in space, they’ll be able to create a 3-dimensional view of events on the Sun’s surface – just in the same way your eyes give you depth perception. They launched in October, 2006 on board a Delta II rocket.

One of the best uses of this binocular vision will be to trace the path of coronal mass ejections; especially the ones headed towards Earth. With STEREO, astronomers will be able to know right away if a CME is headed our way, and can help power companies and satellite operators prepare for some rough space weather. And they’ll be able to give us a better idea of when to head outside and see an aurora.

I think this mission is going to be one of the surprising hits for astronomy fans. Make sure you get a pair of 3-D glasses to really enjoy some of the STEREO movies.

Original Source: NASA STEREO Site

Posted on by Fraser Cain

The Sun Isn’t Responsible for Climate Change

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I recently wrote an article for Wired Science about how there doesn’t appear to be a link between cosmic rays and global warming. Now another argument against human-created global warming has fallen to the wayside: increasing temperatures from the Sun.

It turns out energy output from the Sun has actually been decreasing over the last two decades. And during this period, temperatures across the planet have been steadily rising.

The research was published in the Royal Society’s journal Proceedings A, entitled Recent oppositely directed trends in solar
climate forcings and the global mean surface air temperature. The report covers not only trends in solar output, but also deals with decreasing trends in cosmic rays as well.

The Sun varies on an 11-year cycle between periods of high and low activity. But above this, there’s a longer term trend. For most of the 20th century, output from the Sun was slowly and steadily rising. But in 1985, that trend reversed, with solar output slowly declining. Global temperatures here on Earth continued climbing, unaffected.

If it’s not the Sun, and it’s not cosmic rays, what’s left? Oh right… humans.

Original Source: Royal Society journal Proceedings A

Posted on by Fraser Cain

Astronauts Will Get Some Warning When the Space Storm’s Coming

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One of the great risks of space travel is the threat from solar radiation storms. An unlucky group of astronauts traveling to the Moon could get caught unprotected as a hail of charged particles and radiation blast through the spacecraft. But now NASA researchers think the Solar and Heliospheric Observatory (SOHO) will be able to give astronauts some warning before the big storm hits.

SOHO is normally used for scientific observations of the Sun. But it’s equipped with an instrument called the Comprehensive Suprathermal and Energetic Particle Analyzer (COSTEP), which counts particles coming from the Sun, and measures their energies.

One of the main predictors are electrons, which aren’t dangerous in themselves, but are the first wave of a coming storm. The electrons are lighter than the other particles, so they’re carried out ahead of the heavier, and more dangerous particles. By analyzing hundreds of solar storms, the researchers were able to match electrons with a predicted density of ions.

When SOHO is experiencing one of these electron storms, astronauts traveling to the Moon will be experiencing it as well. And the more dangerous ions and heavier particles are about to arrive. This advance notice will allow the astronauts to retreat to a safer location in the spacecraft and ride out the storm, suffering the minimum radiation damage.

This technique was able to predict all 4 major storms in 2003, providing advance warnings from 7 to 74 minutes.

Original Source: NASA News Release

Posted on by Fraser Cain

Cluster Sees Earth’s Bow Shock Crumple and Reform

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ESA’s Cluster spacecraft were at the right place at the right time to encounter a very special event: the Earth’s bow shock – a wave that forms where the solar wind buffets the magnetosphere – breaking and reforming. This situation was predicted in theory more than 20 years ago, but scientists had never seen it happening in space, until now.

The event occurred on January 24, 2001, when the four spacecraft that make up the Cluster formation were flying at an altitude of 105,000 km above the Earth. Each spacecraft was separated by a distance of about 600 km, allowing them to see space weather events at different times and places. As they approached the bow shock region, scientists expected they’d see roughly the same thing.

Instead, each spacecraft saw large fluctuations in its readings. The magnetic and electric fields were breaking and then reforming further out, like waves build up and crash on shore, and then reform again further out to sea.

Although rare in the Solar System, these kinds of events are very common in the Universe. Photos from Hubble have shown bow shocks form when the intense radiation from young stars blasts into the surrounding stellar nebula.

Original Source: ESA News Release

Posted on by Fraser Cain

Podcast: The Sun, Spots and All

The Sun. Image credit: HinodeIt’s Spring in the Northern Hemisphere, and that means the Sun is back. But it’s more than just a free heat lamp for your garden, it’s an incredible, dynamic nuclear reaction complete with flares, coronal mass ejections, twisting magnetic fields and the solar wind. Put in your headphones, head outside and enjoy the sunshine while you listen to this week’s podcast.
Continue reading “Podcast: The Sun, Spots and All”