Inside Science News Briefs - November 17, 2008

Inside Science News Briefs

November 17, 2008

By Jim Dawson
Inside Science News Service

Birth of Our Solar System Found in Dust from a Comet

Artists’ renditions of the birth of our Sun and our solar system typically show a giant cloud of dust swirling in the vastness of space. As the dust collapses inward, it glows hotter and brighter until it finally creates a hot, dense ball of gas that we know as the Sun. Shortly thereafter, in astronomical time, the planets formed out of the dust and gas rotating around the new sun.

All of this actually happened about 4.5 billion years ago, and scientists studying three tiny granules of what might have been part of that original dust – retrieved from the comet Wild 2 by a spacecraft in 2004 – report that the dust is rich in calcium and aluminum, some of the first minerals to solidify in our fledgling solar system. Scientists at the University of Chicago who are conducting the research named the particles Inti, Inti-B and Inti-C, after the Incan sun god. The minerals contained in the particles, which are each much narrower than a human hair, were likely formed deep inside that primordial dust cloud that created the sun.

While the particles themselves were interesting, they raised the question of how they got from the center of the primordial cloud to an icy comet that scientists believed formed in the outer reaches of the solar system. The existence of the particles in the comet indicates either turbulence within the original dust cloud, or a phenomenon called bipolar outflow from the early sun, said Steven Simon, a geophysical scientists at the University of Chicago. In a paper published in the November issue of Meteoritics and Planetary Science, Simon and 11 other scientists say the discovery of the particles may also indicate that it may be time to rethink how comets form.

“Because they [comets] are loaded with ices we’ve always thought that these are outer solar system objects,” said geophysicist Lawrence Grossman, a coauthor of the study. “But maybe cometary ices formed much closer in, after the inner part of the solar nebula cooled off, and incorporated the high-temperature stuff that formed earlier.” There is a yet another possibility, the scientists said: Perhaps the material in the comet formed around another star, one similar to the sun, and drifted into the outer reaches of our solar system.

All of this from three specks of dust.

Life Complicated? Get Some Sleep.

While science is a long way from truly understanding the role of sleep in our lives, University of Chicago psychologists have just published research showing that sleep helps the mind learn complicated tasks and helps people remember how to do those tasks after they had forgotten how to do them. The test involved teaching groups of college students how to play a complicated video games, and then testing them later on how many of the skills they remembered, and how many they had forgotten. The difference in the scores of the groups correlated with those who slept between learning and playing, and those who didn’t. “Researchers showed for the first time that people who had ‘forgotten’ how to perform a complex task 12 hours after training found that those abilities were restored after a night’s sleep,” a University of Chicago release said.

“Sleep consolidated learning by restoring what was lost over the course of a day following training and by protecting what was learned against subsequent loss,” said psychologist Howard Nusbaum. “These findings suggest that sleep has an important role in learning generalized skills in stabilizing and protecting memory.”

The 200 students involved in the study had little experience with video games, the researchers said. The students were given a pre-test to determine the performance level on the games, then were trained to play. One group was trained in the morning, then tested 12 hours later after being awake the entire time. Another group was trained in the morning and then tested the next morning. Two other groups were trained in the evening and then tested 12 and 24 hours later, respectively. Both of those groups were allowed to sleep after training.

The students who were tested 12 hours after training without sleeping saw their scores drop 50 percent from what they had score immediately after the training. Those who had a night’s sleep had a 10 percent improvement in their score. Those who were trained in the evening and allowed to sleep before being tested again say similar improvements in their scores.

Nusbaum said that during sleep, the distractions of the day were cleared away “and the brain was able to do its work.” The research was published in the current issue of the journal Learning and Memory.

Learning is Easier the Second Time Around

Scientists with the Max Planck Institute of Neurobiology in Martinsried, Germany have discovered why it is easier to relearn something you once knew, then forgot, than it is to learn something new. Researchers have known for many years that learning occurs and memories are created when nerve cells in the brain make new connections with each other. Those points of contact are called synapses, and they allow information to be transferred from one cell to the next. When the connection is broken, so is the memory. “We forget what we learn,” the researchers said.

The scientists wanted to know what happens in the brain when the brain learns something, forgets it, and then has to learn it again. By monitoring cell development in a brain as visual information was sent in, then blocked, then sent in again over several days, the researchers realized that when nerve connections were broken, the cells that held the “memory” of the original information remained, but were taken offline. When the images returned, instead of having to make new cells, the brain simply switched on the old ones.

“Since an experience that has been made [in the brain] may occur again at a later point in time,” said research leader Mark Hubener, “the brain apparently opts to save a few appendages [synapses] for a rainy day.” Hubener and the other researchers on the project said it was an important insight for understanding “the fundamental processes of learning and memory.”


This column is provided for media use by the Inside Science News Service, which is supported by the American Institute of Physics, a not-for-profit publisher of scientific journals. Contact: Jim Dawson, news editor, at jdawson@xxxxxxxx

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