For the first time, a team of astronomers has completed a demographic census of galaxy types at two different points in the Universe's history — in effect, creating two Hubble sequences — that help explain how galaxies form. The survey of 116 local galaxies and 148 distant galaxies indicates that the Hubble sequence six billion years ago was very different from the one that astronomers see today.

Researchers from Case Western Reserve University have designed an ultra-lightweight sponge made of clay and a bit of high-grade plastic they say will effectively clean up spills of all kinds of oils and solvents, and allow for the absorbed oil to be squeezed back out for use.

The new material, called aerogel, is made by mixing clay with a polymer and water in a blender. The mixture is then freeze-dried; air fills the gaps left by the loss of water, and the resulting material is super light, comprised of about 96 percent air, 2 percent polymer and 2 percent clay.

Researchers from Yale and George Mason Universities say that, despite a lack of concern over climate change, the American public is in favor of policies aimed at reducing greenhouse gas emissions and developing cleaner forms of energy.

Scientists have long known that sperm's activity level depends on their internal pH. And now researchers writing in Cell say they have found the channel that allows the tiny cells to rid themselves of protons. Once in the female reproductive tract, that proton release changes their internal environment from acidic to alkaline and begins their race to the finish line. The findings offer new insight into a critical event in human fertilization and may lead to new ways of controlling male fertility.

"The concentration of protons inside the [sperm] cell is 1,000 times higher than outside," said Yuriy Kirichok of the University of California, San Francisco. "If you just open a pore, protons will go outside. We identify the molecule that lets them out."

Writing in the latest issue of Science, researchers say they have identified the vibrant colors that adorned Anchiornis huxleyi, a feathered dinosaur extinct for 150 million years. The discovery may add weight to the idea that dinosaurs first evolved feathers not for flight but for purposes such as sexual selection.

Researchers closely examined 29 feather samples from the dinosaur and measured melanosomes (cellular organelles that contain melanin) within the feathers. A statistical analysis of how those melanosomes compared to the types known to create particular colors in living birds allowed scientists to discern with 90 percent certainty the colors of individual feathers and, therefore, the colorful patterns of an extinct animal.

From an evolutionary perspective, same sex attraction doesn't make much sense. But a pair of psychologists writing in Psychological Science say the "kin selection hypothesis" may explain why the trait has persisted for eons without conferring any discernible reproductive advantage.

The new study suggests that homosexuality may convey an indirect benefit by enhancing the survival prospects of close relatives. Specifically, homosexual men might enhance their own genetic prospects by being "helpers in the nest." By acting altruistically toward nieces and nephews, homosexual men would perpetuate the family genes, including some of their own.

 Data collected since the pre-industrial age indicates that the mean surface pH of the world's oceans has declined from 8.2 to 8.1 units with another 0.4 unit decline possible by century's end, according to a new study in Oceanography. A single whole pH unit drop would make ocean waters 10 times more acidic, which could rob many marine organisms of their ability to produce protective shells – and tip the balance of marine food chains, the study warns.

The delicate balance of life in the waters that surround the frozen continent of Antarctica is especially susceptible to the effects of acidification. The impact on the marine life in that region will serve as a bellwether for global climate-change effects.

Research conducted by scientists at the Weizmann Institute and the University of Maryland reveals that bats, which 'see' with beams of sound waves, skew their beams off-center when they want to locate an object. The research, which recently appeared in Science, shows that this strategy is the most efficient for locating objects.

"We think that this tradeoff between detecting a object and determining its location is fundamental to any process that involves tracking an object whether done by a bat, a dog or a human, and whether accomplished through hearing, smell or sight," said co-author Cynthia Moss, a University of Maryland professor of psychology, who directs interdisciplinary bat echolocation research in the university's Auditory Neuroethology Lab.

Despite the endless anti-smoking campaigns and serious health risks associated with tobacco use, many smokers don't give up the habit. Currently, the smoking quit rate remains discouragingly low. Smokers try to quit on average 12 to 14 times before they succeed, and every year about 41% of smokers try to quit but only 10% succeed.

So what, then, is the best to way to convince smokers to stop for good? Giving them information about their individual risk of serious illness may be a good place to start, according to a paper published in the current issue of the Postgraduate Medical Journal.

You're living as part of a small band of hunter-gatherers 30,000 years ago in what will later become France. How do you explain the fact that a stone, when dropped, falls to the earth? How do you even begin to think about gravity?

People sometimes wrinkle their noses when, in the context of explaining the meaning of the word 'theory' in science, you talk about the 'theory of gravity'. Gravity is a fact, isn't it? But from our 21st century perspective, we take too much of 2000 years of theoretical developments for granted. So try to imagine how you would even begin to think about gravity if you were living in a cave 30,000 years ago.

Aristotle