Sea ice may have extended to the equator 716.5 million years ago, bringing new precision to a "snowball Earth" event long suspected to have taken place around that time, geologists report this week in Science.

The new findings -- based on an analysis of ancient tropical rocks that are now found in remote northwestern Canada -- bolster the theory that our planet has, at times in the past, been ice-covered at all latitudes.

The survival of eukaryotic life throughout this period indicates sunlight and surface water remained available somewhere on the surface of Earth. The earliest animals arose at roughly the same time, following a major proliferation of eukaryotes.

Flowing lava probably carved at least one of the river-like channels on the surface of Mars, according to results of a study presented at the Lunar and Planetary Science Conference at NASA's Goddard Space Flight Center. Whether channels on Mars were formed by water or by lava has been debated for years, and the outcome is thought to influence the likelihood of finding life there.

A low-cost water purification technique that uses seeds from the Moringa oleifera tree can produce a 90.00% to 99.99% bacterial reduction in previously untreated water, according to a paper published in Current Protocols in Microbiology. The method could help drastically reduce the incidence of waterborne disease in the developing world.

"Moringa oleifera is a vegetable tree which is grown in Africa, Central and South America, the Indian subcontinent, and South East Asia. It could be considered to be one of the world's most useful trees," said Michael Lea, a researcher at Clearinghouse, a Canadian organization dedicated to investigating and implementing low-cost water purification technologies.

Scientists writing this week in Geophysical Research Letters say they have pinpointed six spots on the remote Pacific Antarctic Ridge, 1,000 miles from the west coast of Antarctica, where they think  hydrothermal vents are likely to be found.

Two pieces of evidence tipped researchers off to the location of the hidden vents. First, the ocean is stratified with layers of lighter water sitting on top of layers of denser water. Second, when a seafloor vent erupts, it spews gases rich in rare helium-3, an isotope found in earth's mantle and in the magma bubbling below the vent. As helium-3 disperses through the ocean, it mixes into a density layer and stays there, forming a plume that can stretch over thousands of kilometers.

Just as they would in face-to-face dating, people who lie about themselves on internet dating services probably are people-pleasers who want to present themselves in the most favorable light to get someone to like them, according to a study in the Journal of Social and Personal Relationships.

More than 5,000 participants in a national Internet matchmaking service were surveyed to determine what kinds of people are most likely to lie during the online dating process. They were asked how likely they were to lie about topics such as assets, relationship goals, personal interests, personal attributes, past relationships, age and weight.

A newly discovered species that shared many characteristics with dinosaurs but fell just outside of the dinosaur family lived 10 million years earlier than the oldest known dinosaurs. Researchers writing in Nature say the discovery of  Asilisaurus kongwe means that dinosaurs and their close relatives such as pterosaurs (flying reptiles) might have also lived much earlier than previously thought.

The research also suggests that at least three times in the evolution of dinosaurs and their closest relatives, meat-eating animals evolved into animals with diets that included plants. These shifts all occurred in less than 10 million years, a relatively short time by geological standards.