Some U.S. scientists are helping search for evidence of alien life not by looking into outer space, but by studying some rocks right here on Earth.

Some of the rocks are up to 3.5 billion years old. The scientists are looking for crucial information to understand how life might have arisen elsewhere in the universe and guide the search for life on Mars one day.

Agricultural researchers on Tuesday said they had found a gene that boosts the digestibility of sorghum, transforming a humble grain into a potential famine-beater.

Sorghum (Latin name Sorghum bicolor) is a tough tropical cereal grown in dry regions of Africa, India and the southern United States.

An amount of freshwater almost the size of the Dead Sea has been lost in parts of the Middle East due to poor management, increased demands for groundwater and the effects of a 2007 drought, according to a NASA study.

The study, to be published Friday in Water Resources Research, a journal of the American Geophysical Union, examined data over seven years from 2003 from a pair of gravity-measuring satellites which is part of NASA's Gravity Recovery and Climate Experiment or GRACE. Researchers found freshwater reserves in parts of Turkey, Syria, Iraq and Iran along the Tigris and Euphrates river basins had lost 117 million acre feet (144 cubic kilometers) of its total stored freshwater, the second fastest loss of groundwater storage loss after India.

U.S. President Barack Obama on Tuesday told divided lawmakers he will act on climate change even if they do not, vowing to set ambitious long-term goals such as ending the car's dependence on oil.

Obama pledged to promote wind, solar and cleaner natural gas energy in the world's largest economy and called for the United States to cut the energy wasted by homes and businesses by half over the next 20 years.

A sea turtle that lost her front legs to a shark attack was bidding to match "Blade Runner" Oscar Pistorius on Tuesday, as she donned the latest in artificial flipper technology in Japan.

Yu, an approximately 25-year-old female loggerhead turtle, was test-driving her 27th pair of artificial front legs around her home aquarium near Kobe in western Japan, where she proves a draw for the crowds.

The United States launched its latest Earth observation satellite Monday, enhancing an array of orbiting eyes that help with everything from climate change study to urban planning.

The satellite was launched into space atop an Atlas rocket fired from Vandenberg Air Force Base in California, NASA said.

The remains of Julia Pastrana, a Mexican who was paraded in fairs and circuses as the "ape woman" in 19th century Europe, have returned home from Norway 153 years after her death.

Pastrana suffered from a rare disease -- congenital generalized hypertrichosis terminalis, or CGHT -- that covered her face and body with thick hair and gave her fat lips and gums.

"Cassius" has reclaimed his crown as the world's biggest crocodile in captivity after his rival for the title died, with the huge reptile's handler in Australia saying Tuesday it will boost business.

The 5.48-metre (17 ft 11ins) crocodile, kept in a park on an island off Australia's Queensland, held the record until "Lolong", a 6.17-meter suspected man-eater, was caught in the Philippines 17 months ago.

Senior politicians on Monday launched an independent panel into management of the world's oceans, which are facing unprecedented overfishing, pollution and habitat loss.

The Global Ocean Commission is spearheaded by former British foreign secretary David Miliband, ex-Costa Rican president Jose Maria Figueres and South African cabinet minister Trevor Manuel.

World solar power capacity passed the 100 gigawatt mark for the first time to 101 GW, the European Photovoltaic Industry Association (EPIA) said on Monday.

"This global capacity to harness the power of the sun produces as much electricity energy in a year as 16 coal power plants or nuclear reactors of one GW each," the association said in a statement