It's a good thing I already forgot all that I learned in Physics...NASA Finds Direct Proof of Dark Matter
NASA RELEASE 06-297
For Release: August 21, 2006
Erica Hupp/Dwayne Brown Headquarters, Washington (Phone: 202/358-1237/1726)
Steve Roy Marshall Space Flight Center, Huntsville, Ala. (Phone: 256/544-6535)
Megan Watzke Chandra X-ray Center, Cambridge, Mass. (Phone: 617/496-7998)
Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.
"This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.
"A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking," said Doug Clowe of the University of Arizona at Tucson, and leader of the study. "These results are direct proof that dark matter exists."
In galaxy clusters, the normal matter, like the atoms that make up the stars, planets, and everything on Earth, is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter. Without dark matter, which is invisible and can only be detected through its gravity, the fast-moving galaxies and the hot gas would quickly fly apart.
The team was granted more than 100 hours on the Chandra telescope to observe the galaxy cluster 1E0657-56. The cluster is also known as the bullet cluster, because it contains a spectacular bullet-shaped cloud of hundred-million-degree gas. The X-ray image shows the bullet shape is due to a wind produced by the high-speed collision of a smaller cluster with a larger one.
In addition to the Chandra observation, the Hubble Space Telescope, the European Southern Observatory's Very Large Telescope and the Magellan optical telescopes were used to determine the location of the mass in the clusters. This was done by measuring the effect of gravitational lensing, where gravity from the clusters distorts light from background galaxies as predicted by Einstein's theory of general relativity.
The hot gas in this collision was slowed by a drag force, similar to air resistance. In contrast, the dark matter was not slowed by the impact, because it does not interact directly with itself or the gas except through gravity. This produced the separation of the dark and normal matter seen in the data. If hot gas was the most massive component in the clusters, as proposed by alternative gravity theories, such a separation would not have been seen. Instead, dark matter is required.
"This is the type of result that future theories will have to take into account," said Sean Carroll, a cosmologist at the University of Chicago, who was not involved with the study. "As we move forward to understand the true nature of dark matter, this new result will be impossible to ignore."
This result also gives scientists more confidence that the Newtonian gravity familiar on Earth and in the solar system also works on the huge scales of galaxy clusters.
"We've closed this loophole about gravity, and we've come closer than ever to seeing this invisible matter," Clowe said.
These results are being published in an upcoming issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass.
I've been very depressed this past week. I couldn't get out of bed because I was so sad on Friday, so I took the day off work. I was thinking that the medication for depression would help my seasonal affective disorder too, but it doesn't seem like it is going to. Hopefully I can pull out of it this week because I am starting a new class and I have work piling up at my job. I really wish I was normal and didn't have to suffer with my mind.
According to research findings released in 2004, smokers and former smokers did not perform as well on tests as nonsmokers. Four hundred sixty-five subjects had taken a test that measured cognitive ability in 1947 at age 11. They took the test again between 2000 and 2004. Based on the results, smoking appeared to cause a one percent drop in cognitive function. A possible explanation for this correlation is that smoking-related lung damage caused less oxygen to reach people's brains.
Intelligence and Adjustment
One of the stereotypes surrounding gifted children is that they have trouble fitting in at school. Several scientific studies suggest that the stereotype has a foundation in reality. A Purdue University study of 423 gifted students suggested that they were susceptible to bullying. A 20-year study of gifted children ending in 1940 suggested that the trend of not fitting in continues into adulthood. The study used a test that measured both verbal intelligence and personal adjustment. People who scored above 140 in verbal intelligence generally had lower personal adjustment scores.
Are We All Getting Smarter?
For several years, scientists have noticed a general upward trend in the general population's IQ scores. It has seemed that each generation is a little smarter than the one before it. Researchers aren't sure whether improvements in education, nutrition, medical care or society in general are responsible for this trend, which is known as the Flynn effect.
People with savant syndrome are often described as geniuses. Savant syndrome is a rare condition that typically affects people who are autistic or have developmental disabilities. People with savant syndrome excel spectacularly at some particular task or skill. The 1988 film "Rain Man" depicted a man with the syndrome. You can learn more about it at the Wisconsin Medical Society's Savant Syndrome Web site.
After studies showed that listening to Mozart could raise IQ scores, parents started playing Mozart for babies, hoping to take advantage of the "Mozart effect." One explanation for the effect is that music makes people more awake and alert. Another is that listening to Mozart and mathematical or spatial reasoning tasks rely on the same neurons within the brain. However, none of the studies involving Mozart's music have used babies as test subjects, and the Mozart effect in adults is usually temporary.
¶ 11:22 AM
Nature's first green is gold,
Her hardest hue to hold.
Her early leaf's a flower;
But only so an hour.
Then leaf subsides to leaf.
So Eden sank to grief,
So dawn goes down to day.
Nothing gold can stay.