Forgetting an umbrella or the location of a parking spot may be annoying, but scientists have suggested that for healthy brains to function well, they need to forget. By forgetting, scientists say, the brain makes space for new memories. In an intriguing breakthrough, researchers from the United States and China have identified the protein responsible for forgetting in fruit flies. By tweaking a protein called Rac, researchers were able to speed up and slow down the erasure of painful memories [New Scientist]. The findings were published in the journal Cell.

Scientists have been unable to pinpoint why people forget. Some have suggested that new memories are ephemeral and vanish over time, while others thought that interference caused earlier short-term memories to be overridden as new information comes in [Science Daily]. While both of these notions seem to suggest that forgetting is a passive mechanism, the new study suggests that forgetting is far more active, and that Rac works to inhibit the formation of more long-term memories.

The scientists studied fruit flies that were exposed to two fly-repellent odors, the second of which came with an electric shock. The flies quickly learned to head to the odor that didn’t cause them pain. Then the scientists switched the set-up, linking the first odor to the shock instead. Regular flies quickly noted the change, discarding the old memory of which odor came with a shock and learning to head towards the now-safe second odor. But when the experiment was repeated after the memory-eroding protein [Rac] was blocked, there was utter confusion. The flies had not erased their first memory, and had made a second memory. Unable to pick which odor to fly toward, they zigzagged back and forth [The New York Times].

The researchers determined that when Rac was switched on, newly formed memories faded fast, allowing new memories to come in and solidify. When Rac was switched off in the fruit flies, new memories lingered longer, extending from the normal limit of just a few hours to more than a day.

The scientists next hope to test the effects of meddling with the proteins in mice. If this mechanism holds true in mammals, it could shed light on the molecular basis of forgetting in humans [New Scientist], as humans also have the Rac protein. The researchers suggest that the identification of this protein could potentially help create techniques to enhance cherished memories or to forget painful episodes, which could be a boon to those who suffer from post-traumatic stress disorder (PTSD). Until now approaches to erasing unwanted memories have largely focused on interfering with the laying-down of memories, rather than our natural ability to forget [New Scientist].

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Image: flickr / Image Editor

Light pollution map. I snarfed it from Urban Ecoist

It’s almost time for the 5th Annual Globe at Night project.  Five years already!!  If you have not participated in this past oh, you just have to give it a go.  Super simple, you need only to follow some easy steps and you too can contribute to map light pollution.  Basically you go out and look up at the sky.  There is two week window so you have a good chance at clear skies.

I am really looking forward to this, last year I could see a difference from the year before.  The Globe at Night folks do such a great job at this too.  You can go the GAN site and get all the information you need including star charts (don’t worry it’s EASY) and they even have a Family Activity Packet.  If you are a teacher at ANY LEVEL you can make a great class project out of this and yes instructions for doing so are on the site too.

I am giving you plenty of heads up and I hope to put a banner for the side bar to remind you.  Last year there were over 15,000 observations, so let’s try and get that number up if we can.

PLEASE TRY AND PARTICIPATE IN THIS GREAT PROJECT!!!

Here’s the scoop:

The 5th Annual Globe at Night Campaign: 3-16 March 2010

What: The Globe at Night Campaign
When: 8pm to 10pm local time, March 3-16, 2010
Where: Everywhere
Who: You! (Everyone!)
How: See http://www.globeatnight.org

Why:
With half of the world’s population now living in cities, many urban dwellers have never experienced the wonderment of pristinely dark skies and maybe never will. This loss, caused by light pollution, is a concern on many fronts: safety, energy conservation, cost, health and effects on wildlife, as well as our ability to view the stars. Even though light pollution is a serious and growing global concern, it is one of the easiest environmental problems you can address on local levels.

Globe at Night is an annual 2-week campaign in March that helps to address the light pollution issue locally as well as globally. This year the campaign is March 3-16, 2010. You are invited along with everyone all over the world to record the brightness of your night sky by matching its appearance toward the constellation Orion with star maps of progressively fainter stars found at http://www.globeatnight.org/observe_magnitude.html. You then submit your measurements on-line at http://www.globeatnight.org/report.html with your date, time and location. A few weeks later, organizers release a map of light-pollution levels worldwide. Over the last four 2-week Globe at Night campaigns, volunteers from over 100 nations have contributed 35,000 measurements.

To learn the five easy steps to participate in the Globe at Night program, see the Globe at Night website at http://www.globeatnight.org. You can listen to our 10-minute audio podcast on light pollution and Globe at Night at http://365daysofastronomy.org/2010/02/03/february-3rd-the-globe-at-night-campaign-our-light-or-starlight/

For activities that have children explore what light pollution is, what its effects are on wildlife and how to prepare for participating in the Globe at Night campaign, see the new activities at http://www.darkskiesawareness.org/DarkSkiesRangers.

Monitoring our environment will allow us as citizen-scientists to identify and preserve the dark sky oases in cities and locate areas where light pollution is increasing. All it takes is a few minutes during the March 2010 campaign to measure sky brightness and contribute those observations on-line. Help us exceed the 15,000 observations contributed last year. Your measurements will make a world of difference.

On November 21, 2009, the Cassini spacecraft sliced past Saturn’s moon Enceladus, shaving the iceball at a distance of 1600 km (1000 miles). From that distance, the view was astonishing…

It’s been known for some time that the south pole of Enceladus is lousy with geysers, erupting water into space (though the ultimate source of the water is still a bit of a mystery). But this new pass shows 30 geysers, 20 more than were previously seen! One major geyser also appears to have waned a bit since the last pass, showing that not only is stuff going on, but things are changing, too.

This mosaic of the surface of Enceladus overlays a high-res optical image with thermal hot-spots. You can see that the hottest parts — which are actually at -90° C (-140° F), so I guess "hot" is in the (frozen) eye of the beholder — line up along a huge fracture in the moon’s surface. The fracture is called Baghdad Sulcus and is one of the places on the moon erupting water geysers. The fracture is about 500 meters (roughly 1/4 mile) deep, and this image shows about a 40 km (25 mile) swath along it. There’s evidence of particles from the geysers re-falling here, and also house-sized icy blocks that may be rubble that has been seismically shaken and settled downslope.

There’s a lot of science in those images, and in the others returned from that close pass. But I think my favorite from these is one that may also have scientific value, but, like almost everything Cassini sends back, is perhaps more striking for its artistry.

That’s a crescent Enceladus, replete with geysers, and its parent planet Saturn in the foreground. Wow, that’s pretty. I love how gray Enceladus looks and how much brighter Saturn is. I was thrown for a moment; Enceladus has a reflectivity of nearly 100%, meaning it reflects nearly all the light hitting it, while Saturn only reflects 30-50% of the light that hits it (depending on how you measure it). But this depends on the viewing geometry! Enceladus is thin crescent, so the light is hitting it at a very low angle. A lot of the light hitting the moon is sent straight back toward the source (the Sun), so not much of that light gets sent off in other directions. It’s not that Enceladus is intrinsically fainter than Saturn, it’s just that the light is reflected off in another direction, and not towards Cassini in this image.

As in life, sometimes what you see depends on how you look.

Cassini has been orbiting Saturn since 2004, and in all that time it has not disappointed. It continues to return a veritable bounty of information about Saturn and its fleet of moons. If you want to stay on top of Cassini news, subscribe to the email list, and follow imaging team leader Carolyn Porco on Twitter!

For everyone out there who’d like to hear a little less of their amorous neighbors, not to mention their kid badly playing the violin, there may be hope: Hong Kong scientists have devised a delightfully simple material made of latex and plastic that they say could one day reduce the racket at noisy places like airports. The paper appears in Applied Physics Letters.

Zhiyu Yang and colleagues devised a system of thin tiles that, when assembled into a large sheet, could cancel out noise in a huge range, including the bass frequencies that tend to breach the walls of our apartments and houses with ease. Each panel is just three millimeters thick, and less than half an inch wide, with the weighted plastic button in the middle. When sound waves hit the panel, the membrane and weighted buttons resonate at difference frequencies. “The inner part of the membrane vibrates in opposite phase to the outer region,” says Yang. That means the sound waves cancel each other out and no sound gets through [New Scientist]. The large pieces of foam that insulate most modern houses can block out many sounds, but unfortunately, low-frequency sound waves usually will penetrate them. That’s because bass sounds in the air can be several yards in wavelength and get longer in a solid. Creating a thin soundproofing material that can block low-frequency sounds has proven extremely difficult. For instance, a thin latex membrane by itself cannot resonate at the right frequency to either absorb or reflect the bass rumble of a jet taking off [Popular Science].

But, Yang says, each thin layer can be tuned to cancel sound waves of particular frequencies by changing the weight of the button. So several layers stacked on top of one another could create a surface impervious to sounds at a wide range. And the panel’s weight is equivalent to ceramic bathroom tiles, “although it’s slightly thicker at 15 millimetres”, he adds [New Scientist].

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