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What Do You See When SETI’s Allen Telescope Array Is Aimed At The Sun?

A comparison between an observation of the sun using the ATA's 2.75 GHz band (left) and SOHO's 195A filter. Both are near-simultaneous observations on Oct. 1, 2009 (Saint-Hilaire et al., 2011).

And no, “aliens” isn’t the answer.

The Allen Telescope Array (ATA), located near Hat Creek, California, isn’t only used by the SETI Institute to seek out signals from extraterrestrial civilizations. The 42 6.1-meter antennae form an interferometer that can be used for a variety of astronomical studies — in reality, this is the main focus of the project. SETI studies “piggyback” the active astronomical research, passively collecting data.

Due to the radio interferometer’s wide field of view, one surprising use of the ATA is solar astronomy — at radio frequencies. The ATA can be used to simultaneously observe the whole of the solar disk at a range of frequencies rarely studied. As outlined in a recent arXiv publication, a University of California, Berkeley, team of astronomers headed by Pascal Saint-Hilaire have carried out the first ATA solar study, producing images of the sun in a light we rarely see it in (shown above).

According to the paper, active regions were observed at radio and microwave frequencies, spotting the emissions associated with bremsstrahlung — electromagnetic radiation generated by accelerated charged particles caught in intense magnetic fields, a feature typical inside solar active regions. Also, coronal interactions, or gyroresonance, between solar plasma and plasma waves (propagating along magnetic field lines) was detected.

Combining the ATA’s wide field of view, range of frequencies and high resolution, it looks like the ATA is the only solar radiotelescope on the planet.

For more on this fascinating study, read “Allen Telescope Array Multi-Frequency Observations of the Sun,” Saint-Hilaire et al., 2011. arXiv:1111.4242v1 [astro-ph.SR]

The Sun Has An Anti-Climax

The solar disk on May 11th: Is it? Are they? Not quite (SOHO)

Some recent solar articles are freaking out, proclaiming that the Sun is waiting to unleash it’s fury on the Earth (re: Warning: Sunspot cycle beginning to rise) or that it’s lowering its energy output, possibly kickstarting Maunder Minimum 2.0 (re: New Forecast Calls for Calmer Sun).

So which one is it? Is the Sun just biding its time, waiting for the perfect moment to fire a salvo of flares at us? Or will it remain quiet, well into Solar Cycle 24, impacting our planet like the Maunder Minimum did during the Little Ice Age from the 16th-19th century?

It’s funny actually, both the above articles are based on the same research, and yet two very different conclusions were drawn from the text.

On the one hand, the Sun is acting rather strange; it’s undergoing a sustained solar minimum, the longest period of low sunspot population for the best part of a century. On the other hand, when the Sun does get active, steadily growing to a peak in activity for the 2012-2013 predicted solar maximum, the resulting flares and coronal mass ejections (CMEs) could inflict $2 trillion in damages on global infrastructure (according to a recent study), leaving us to mop up the mess for a decade. It’s these two extremes that are causing such a stir, generating the attention-grabbing headlines.

However, I seriously doubt that we are facing another Little Ice Age and I am highly skeptical of the predictions that the 11 years of Cycle 24 are going to be overly violent. To be honest, we just don’t know. Considering we live so close to the Sun, we actually know very little about it; to even begin trying to predict what it’s going to do next remains problematic.

That said, once the Sun starts producing lost of sunspots, this means magnetic activity is on the rise and solar activity is increasing, so when I see sunspots rotate into view, I can’t help but be a little excited. Today, it happened, two active regions appeared on the disk of the Sun. Could this be the real start to the solar cycle?

Today’s image is a magnetic map of the sun. Two active regions are circled. Their polarity identifies them as members of new Solar Cycle 24, but they lack the dark cores required of true sunspots. So, in spite of these lively magnetic imprints, we must still say “the sun is blank–no sunspots.” —SpaceWeather.com

No sunspots, another blank disk day and therefore low magnetic activity still.

How dull.

Introducing Little SDO

Playing on our love for WALL-E, our amazement for the Pixar Lamp and some great animation, Chris Smith, an employee at NASA Goddard Flight Center, has given the upcoming Solar Dynamics Observatory a personality.

Apart from obviously having too much time on his hands, Smith is a very talented guy (as all NASA employees are) and is showing that, once again, the space agency is doing a fantastic job of reaching out to the public.

As proven by the efforts of the Phoenix Mars Lander team in 2008, communication goes a long way and by harnessing social media, NASA can make its missions household names. Phoenix was tweeting, blogging and podcasting to its hearts content for five months, from touchdown to frozen death; it was Big Brother for robots living on Mars.

Now most NASA missions have Twitter feeds and devoted blogs, ensuring everyone’s interest is piqued. It also helps to have a Twitter feed talking in first-person, giving these brave rovers, landers, orbiters and probes a much needed personality.

So now, Chris Smith has done something very cool with the SDO; he’s given it an animated personality in a short animation reminiscent of a movie teaser for an upcoming Disney-Pixar feature film. Behold, the Little SDO:

“It’s a really fun little piece,” says Wade Sisler, a television producer for NASA. “And we’re hoping to use it as a way of waking some kids and folks up to solar science.”

And so NASA should, I like it! It’s going to get people interested in a comparatively small mission, and let’s face it, the satellite lacks character (the boxy 4-eyed robot doesn’t do much for me). However, now that Smith has added squeaky solar panel wings, and blinking “eyes” (without changing the design of the craft at all), he’s boosted the SDO’s likeability. Suddenly I care for the little guy. I hope he doesn’t get hit by a solar flare.

Due for launch in October, the SDO will be inserted into a geosynchronous orbit above New Mexico, gathering data from the Sun, so solar physicists can better understand space weather. The cool thing is that with those four eyes, the SDO will capture high-definition images of the Sun continuously.

It might not have the dazzle of the Phoenix Mars Lander, but it has a personality and people will love him (I await the Twitter feed).

Learn more about the Solar Dynamics Observatory »

Source: Wired Science

C.A.T. Scans of the Solar Wind

Guest article by Dr. Mario M. Bisi (Research Focus)

A cut in the ecliptic plane through a 3D reconstruction on 08 November 2004 at 0000 UT using white-light data from SMEI. The view is from directly North of the ecliptic; the Sun is at the centre marked by a +, the Earth is on the right marked with a ⊕ along with its orbit as a black near-circular line around the Sun (the Earth orbits anti-clockwise around the Sun from this point of view). The darker the colour, the greater the density of material in the ecliptic. (©Dr. Mario M. Bisi)

The Computer Assisted Tomography (C.A.T.) technique has been used for many years now and is well known for use on people where certain health conditions need more thorough, detailed, and deeper scans into the human body and the need for three-dimensional (3D) reconstructed imaging. However, similar such scans can also be used on the solar wind to discover the shapes and sizes of structures near Earth and throughout the inner heliosphere in three dimensions. These scans have been carried out for some time, pioneered in the most part by those at the Center for Astrophysics and Space Sciences (CASS), University of California, San Diego (UCSD) in La Jolla, CA, U.S.A. in close-collaboration with the Solar-Terrestrial Environment Laboratory (STELab), Nagoya University, Toyokawa, Japan…
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When the Sun is So Boring, Anything Becomes Interesting

Caption: So boring it doesn't deserve a caption (NASA/SOHO)

You know when you have those unremarkable days, those periods of time you experience you know you’ll forget tomorrow? It’s either “just another” day at work, another commute, or a Sunday where you had a beer, fell asleep, only to wake up again to realise it was too late to get up so you stayed in bed till Monday? (And no, I don’t make a habit of that. I’m sure to have at least two beers.) Most days aren’t like that for me, usually I can think of one noteworthy event that sets apart one day from the next, but sometimes it’s as if Stuff Happens™ doesn’t.

It would appear the Sun is having an extended period of time where Stuff Happens™ is at a premium, so you have to make the most of when something really does happen. In this case, the Sun released a crafty CME, thinking we wouldn’t see it…
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