Posted on by Jason Major

How Did Comet Lovejoy Survive Its Trip Around The Sun?

Comet Lovejoy re-emerging from behind the Sun on Dec. 15, 2011. (NASA/SDO)

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It was just about three months ago that the astronomy world watched in awe as the recently-discovered comet Lovejoy plummeted toward the Sun on what was expected to be its final voyage, only to reappear on the other side seemingly unscathed! Surviving its solar visit, Lovejoy headed back out into the solar system, displaying a brand-new tail for skywatchers in southern parts of the world (and for a few select viewers above the world as well.)

How did a loosely-packed ball of ice and rock manage to withstand such a close pass through the Sun’s blazing corona, when all expectations were that it would disintegrate and fizzle away? A few researchers from Germany have an idea.

Scientists from the Max Planck Institute for Extraterrestrial Physics and the Braunschweig University of Technology have hypothesized that Comet Lovejoy managed to hold itself together through the very process that, to most people, defines a comet: the outgassing of sublimated icy material.

As a comet near the Sun, the increased heating from solar radiation causes the frozen materials within the nucleus to sublimate — go directly and suddenly from solid to gas, skipping the liquid middle stage — and, in doing so, burst through the surface of the comet and create the long, hazy reflective tail that is so often associated with them.

Overview of the forces acting on sungrazing comets. (Illustration from paper.)

In the case of Lovejoy, which was on a direct path toward the Sun, the sublimation itself may have provided enough outward force across its surface to literally keep it together, according to the team’s research.

“The reaction force caused by the strong outgassing (sublimation) of the nucleus near the Sun acts to keep the nucleus together and to overcome the tidal disruption,” the paper claims.

In addition, the team states that the size of the comet’s nucleus can be derived using an equation that takes into consideration the combined forces of outgassing, the material composition of the comet’s nucleus, the comet’s own gravity and the tidal forces exerted by the comet’s close proximity to the Sun (i.e., the Roche limit).

Using that equation, the team concluded that the diameter of Comet Lovejoy’s nucleus is anywhere between 0.2 km and 11 km (.125 miles and 6.8 miles). Any smaller and it would have lost too much material during its pass (and had too little gravity); any larger and it would have been too thick for outgassing to provide enough counterbalancing force.

If this hypothesis is correct, taking a trip around the Sun may not mean the end for all comets… at least not those of a certain size!

Watch the video of Lovejoy’s Dec. 15 solar swing below:

The paper was submitted to the journal Icarus on March 8, 2012 by Bastian Gundlach. See the full text here.

Posted on by Jason Major

Huge Coronal Hole Is Sending Solar Wind Our Way

SDO AIA 211 image showing a large triangular hole in the Sun's corona on March 13

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An enormous triangular hole in the Sun’s corona was captured earlier today by NASA’s Solar Dynamics Observatory, seen above from the AIA 211 imaging assembly. This gap in the Sun’s atmosphere is allowing more charged solar particles to stream out into the Solar System… and toward Earth as well.

Normally, loops of magnetic energy keep much of the Sun’s outward flow of gas contained. Coronal holes are regions — sometimes very large regions, such as the one witnessed today — where the magnetic fields don’t loop back onto the Sun but instead stream outwards, creating channels for solar material to escape.

The material constantly flowing outward is called the solar wind, which typically “blows” at around 250 miles (400 km) per second. When a coronal hole is present, though, the wind speed can double to nearly 500 miles (800 km) per second.

Increased geomagnetic activity and even geomagnetic storms may occur once the gustier solar wind reaches Earth, possibly within two to three days.

The holes appear dark in SDO images because they are cooler than the rest of the corona, which is extremely hot — around 1,000,000 C (1,800,000 F)!

Here’s another image, this one in another AIA channel (193):

AIA 193 image of the March 13 coronal hole

Keep up with the Sun’s latest activity and see more images on NASA’s SDO site here.

Images courtesy NASA, SDO and the AIA science team.

Posted on by Jason Major

Valuable Space Rock Crashes Into Oslo Cabin

This meteorite struck the Thomassen family's cabin in Oslo. (Photo: Rune Thomassen)

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A family in Oslo got a surprise when they visited their allotment garden cabin for the first time this season and found that a 585-gram (20 oz.) meteorite had ripped a hole through the roof. The space rock was discovered “lying five or six metres away,” the cabin’s owner, Rune Thomassen, told the local newspaper VG.

Such an event is rare in Norway; since 1848 the country has noted only 14 meteorite discoveries.

Astrophysicist Knut Jørgen Røed Ødegaard from the University of Oslo investigated the report and found it to be genuine.

“You can tell immediately that it’s genuine from the burned crust, and you can also recognize it from how rough and unusual it is. It gives me goosebumps,” Ødegaard told VG.

NASA Astrobiology Institute’s Hans Amundsen noted the meteorite’s unusual composition: “This is a very rare meteorite because you can see from the cut of it that it contains fragments from many different kinds of rock that have cemented together, forming a so-called breccia.”

Such meteorites are caused by previous collisions, cementing together different types of material from impacts with asteroids or planets.This means the meteorite that landed on the Thomassens’ cabin may very well have been blown off the surface of Mars at some point in the distant past!

“This is unique. This is double-unique,” Ødegaard noted to VG.

According to Amundsen, such a meteorite is very valuable to researchers as well as private collectors, who may be willing to pay highly for it. Chunks of Mars have fetched USD $877 per gram in the past… making the Thomassens’ find potentially worth over $500,000!

Norway’s geological museum has the country’s only meteorite collection “and they’re the right ones to determine what kind of meteorite this is,” Amundsen said.

Read more on this story here, and see coverage with photos and video on the VG site here (in Norwegian).

Posted on by Jason Major

Erasure and VLT Team Up for ESO’s 50th Anniversary

Erasure's Andy Bell in front of ESO's Very Large Telescope array. Credit: S. Lowery/Erasure/ESO.

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British synthpop band Erasure released a video today featuring lead singer Andy Bell in front of the telescopes of ESO’s Paranal Observatory, located high in the mountains of Chile’s Atacama Desert. The new single “Fill Us With Fire” honors ESO’s 50th anniversary this year. Watch the full video below!

The video features the Very Large Telescope as well as some of ESO’s stunning images of the night sky. This is the third single to be released from their 2011 album Tomorrow’s World.

According to ESO’s press announcement:

Andy spent one day at Paranal in February 2012, during which time footage was shot of him singing Erasure’s latest single. The footage was edited with some of ESO’s best astronomical images. Andy, thrilled with the result, decided to dedicate it to ESO’s 50th Anniversary and make it the exclusive video for the single.

Shooting the Fill Us With Fire video. (F. Huber/Erasure/ESO)

Standing on a 20-foot-high platform in front of the VLT, Andy didn’t have a lot of room to move around during the shooting of the video. Say what you will about the choreography, I think it’s awesome to see the observatory and some of its amazing images featured in a new music video!

Personally, I would have wanted to be standing on top of one of the telescope domes but I’m not sure if that’s allowed.

Credit: Erasure/ESO (S. Lowery)

Directed by: Simon Lowery

Editing: Simon Lowery, Lars Lindberg Christensen & Patrick Geeraert

Music: Erasure/Andy Bell

Footage and photos: ESO, Guillaume Blanchard & Simon Lowery

Posted on by Jason Major

Still Concerned About 2012?

Don’t be.

Don Yeomans, senior research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, CA, was kind enough to address some common questions regarding 2012, such as the much-misunderstood Mayan “long-count” calendar, Nibiru, pole-reversal and other such purported “doomsday” devices. Check it out.

Still set on the world ending come Dec. 21?

Back off, man. Don’s a scientist.

Posted on by Jason Major

Active Region Is Still Active!

Aurora over Faskrudsfjordur, Iceland on March 8, 2012. © Jónína Óskarsdóttir.

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Even though the CME unleashed by active region 1429 initially hit Earth a bit softer than expected yesterday (read why here), it ended up gaining some extra “oomph” once the magnetic fields lined up right… enough to ignite some amazing displays of aurorae like the one shown above over Iceland, photographed by Jónína Óskarsdóttir!

And that wasn’t the last we’d hear from AR1429 either; at around 10:30 pm EST on March 8, the region lit up again with an M6.3 flare… although smaller than the previous X5.4-class flare, it produced a temporary radio blackout and released another Earth-directed CME, which is expected to arrive in the coming hours.

Dr. Alex Young, solar physicist at NASA’s Goddard Space Flight Center, reported this morning on his blog The Sun Today:

The flare produced a temporary radio blackout as well as a possible Earth directed CME. We will have to wait and see. The sunspot group still shows potential for more activity as the region sits near the central meridian of the Sun. Facing directly at Earth this is a prime location to produce more geo-effective solar activity.

Here is a look at the flare captured by the 131 Angstrom wavelength camera on the Solar Dynamics Observatory (SDO). This shows us the super hot 5-10 million degree plasma produced by the solar flare.

M6.3-class flare from AR1429. (NASA/SDO/AIA team)

Dr. Young also noted that bright aurorae could be visible in lower latitudes as a result of the latest CME, expected to impact Earth at 1:50 am EST:

Aurora watchers at higher latitudes such as the northern US should keep their eyes out in the early morning and maybe even into tonight depending upon how this storm progresses. 

Many times the size of Earth, active region 1429 has been the source of at least five significant flares over the past week. As it moves across the face of the Sun, its shape has become more and more complex — a sure sign, notes Dr. Young, that magnetic forces within it are twisting further and further towards a breaking point. And when they snap, there’s a flare.

“It’s interesting, they kind of look like a mole,” Dr. Young said during an interview on March 8. “And when you monitor a mole, they tell you as long as it stays in a nice symmetric shape and it doesn’t become really complicated and complex, it’s okay. It’s the same sort of thing with sunspots… when they become complicated and twisted, then that mean the magnetic fields inside of them have become more twisted, like a rubber band twisting around until little knots pop up in it. And right now we have been monitoring that sunspot and it is getting more complex.”

(See a photo of AR1429 taken from New Mexico!)

As far as the effects we see here on Earth are concerned, that’s all about the resulting CME — the enormous cloud of charged solar particles that gets blown out into the Solar System. If that cloud impacts Earth’s magnetic field, and if the direction of the cloud happens to be opposite the direction that Earth’s magnetic field is pointed, a lot of energy is “pumped into” our magnetosphere, resulting in a geomagnetic storm.

AR1429 (NASA/SDO/HMI Intensitygram)

During yesterday’s CME impact the Earth’s magnetic field was pointed north — the same direction as the CME. As a result much of the solar material simply flowed along and over it. But the wake ended up getting caught up in the south-directed part of the field, ramping up the energy index (measured as Kp) as the hours progressed. As yet there’s no way to know for certain how a particular CME will align with Earth’s magnetic field.

According to physicist Dr. Philip Scherrer of Stanford University, “we still need better — or perhaps faster — models” to be able to accurately predict the orientation of incoming CMEs. “We are perhaps a few years of research away from completing the picture.”

Currently the geomagnetic storm level is at G3, which according to the NOAA’s Space Weather Scale could result in voltage problems on power systems, increased drag on satellites and “intermittent satellite navigation and low-frequency radio navigation problems… and aurora has been seen as low as Illinois and Oregon.”

So keep an eye out for northern lights in tonight’s skies, and stay tuned for more updates!

Thanks to Dr. Alex Young  for the information! You can follow him on Facebook and Twitter and on his personal blog The Sun Today. Also thanks to Dr. Phil Scherrer at Stanford University and SpaceWeather.com for the heads-up on Jónína’s photo. See more of her aurora photography here. (Used with permission.)

Posted on by Jason Major

Playing With Water… in Space!

Expedition 30 astronaut and chemical engineer Don Pettit continues his ongoing “Science off the Sphere” series with this latest installment, in which he demonstrates some of the peculiar behaviors of thin sheets of water in microgravity. Check it out — you might be surprised how water behaves when freed from the bounds of gravity (and put under the command of a cosmic chemist!)

See more Science off the Sphere episodes here.

Posted on by Jason Major

Giant Sunspot Seen Through Dusty Skies

Sunspot region 1429 photographed from New Mexico. © David Tremblay.

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The enormous sunspot region responsible for all the recent fuss and flares was easily visible from Earth yesterday… easily visible, that is, with the help of a natural filter provided by a New Mexico dust storm!

Photographer David Tremblay captured this image on March 7 through the dust-laden sky of Alto, New Mexico. Active Region 1429 can be seen on the upper right side of the Sun’s disk. Many times the size of Earth, this sunspot region has already erupted with several X-class solar flares and sent numerous CMEs our way — with potential for more to come!

“Blowing dust from the Tularosa Basin is so very dense that observing the sun was possible with the naked eye this evening,” noted David on SpaceWeather.com, where you can see more of his solar photos taken about the same time.

The image above was captured at 560mm with a Canon MKlll ESO1D.

View more of David’s photography here.

Image © David Tremblay. All rights reserved. Used with permission.

Posted on by Jason Major

Best Views Yet of Historic Apollo Landing Sites

LROC image of the Apollo 11 landing site, acquired Nov. 5, 2011 (NASA/GSFC/Arizona State University)

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Just over 42 years after Neil and Buzz became the first humans to experience the “stark beauty” of the lunar surface, the Lunar Reconnaissance Orbiter captured the remnants of their visit in the image above, acquired Nov. 5, 2011 from an altitude of only 15 miles (24 km). This is the highest-resolution view yet of the Apollo 11 landing site!

The Lunar Module’s descent stage, a seismic experiment monitor, a laser ranging reflector (LRRR, still used today to measure distances between Earth and the Moon) and its cover, and a camera can be discerned in the overhead image… as well as the darker trails of the astronauts’ bootprints, including Armstrong’s jaunt eastward to the rim of Little West crater.

The crater was the furthest the Apollo astronauts ventured; in fact, if you take the total area Neil and Buzz explored it would easily fit within the infield of a baseball diamond!

Neil Armstrong’s visit to the crater’s edge was an unplanned excursion. He used the vantage point to capture a panoramic image of the historic site:

Panorama of the Apollo 11 site from Little West crater. (NASA)

“Isn’t that something! Magnificent sight out here.” Armstrong had stated before he was joined by Aldrin on the lunar surface. “It has a stark beauty all its own. It’s like much of the high desert of the United States. It’s different, but it’s very pretty out here.”

Previously the LROC captured the Apollo 15 landing site, which included the tracks of the lunar rover — as well as the rover itself! And, just yesterday, the LROC site operated by Arizona State University featured the latest similarly high-resolution view of the Apollo 12 site. This location has the honor of being two landing sites in one: Apollo 12 and the Surveyor 3 spacecraft, which had landed on April 20, 1967 – two and a half years earlier!

The Apollo 12 landing site in Oceanus Procellarum. (NASA/GSFC/Arizona State University)

Even though the US flag planted by Apollo 12 astronauts Pete Conrad and Alan Bean isn’t itself visible, the shadow cast by it is.

Apollo 12 was the only mission to successfully visit the site of a previous spacecraft’s landing, and it also saw the placement of the first Apollo Lunar Surface Experiments Package (ALSEP), which included a seismometer and various instruments to measure the lunar environment.

Read more about this image on the LROC page here, and check out the video tour below of the Apollo 12 site.

Images and video courtesy of NASA/GSFC/Arizona State University