Three astronauts returned safely to Earth from the International Space Station early Saturday, aboard a Russian capsule which landed on the freezing Kazakhstan steppe, mission control said.

"There is landing!" flashed a Russian mission control center message transmitted by NASA. Rescue teams rushed to recover the capsule carrying NASA U.S. astronaut Kevin Ford and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin.

Scientists digging a new railway in London have uncovered 13 skeletons that will be tested to see if they died from the Black Death plague in the 14th century.

The lead archaeologist of the Crossrail project, Jay Carver, says the location of the bodies and historical records suggest that the skeletons were found in a burial ground that opened at the start of the plague. Carver says scientists will study the bones to establish cause of death, and hope to map the DNA signature of the plague bacteria.

Some primitive birds boasted four wings, before evolution led them to ditch their hind feathers in favor of webbed or scaly feet, scientists in China said on Thursday.

Previous research had uncovered the existence of bird-like dinosaurs with hind limb feathers, but evidence has remained slim in birds, which are widely believed to have evolved from dinosaurs.

The return to earth of two Russian cosmonauts and an American astronaut from the International Space Station was delayed Friday due to harsh conditions at the Kazakhstan landing site, the Russian space agency said.

The return was postponed until Saturday due to a snow storm and icy conditions which would hamper rescue helicopters deployed at such Soyuz landings.

Whales that beach themselves in large groups are not all members of the same family, a study has found, undermining long-held assumptions about the cause of mass strandings.

An international team of scientists studied 12 mass strandings in Australia and New Zealand to examine the theory that healthy whales beach themselves while trying to help sick or disorientated family members who have run aground.

The European Space Agency (ESA) said it signed a deal on Thursday with its Russian counterpart to launch two unmanned missions to Mars, a quest that was rocked by a U.S. pullout last year.

Called ExoMars, the scheme entails sending an orbital probe to the Red Planet in January 2016 to look for atmospheric traces of methane gas, a pointer to the existence of microbial life.

In its exuberant childhood, the Universe created galaxies that were vast star-making machines, astronomers reported on Wednesday.

Using a brand-new telescope in Chile's Atacama desert, the team snared light that took more than 12 thousand million years to reach them.

The world's biggest radio telescope is being launched in a plateau high above Chile's Atacama desert.

The Atacama Large Millimeter/submillimeter Array, or ALMA, will search for clues about the dawn of the cosmos — from the coldest gases and dust where galaxies are formed to the energy produced by the Big Bang.

Scientists said Wednesday they had unravelled the genetic code of the tapeworm, unearthing data that should lead to more efficient drugs against the dangerous intestinal parasite.

Tapeworms are among the first known parasites of humans, recorded by Hippocrates and Aristotle as long ago as 300 BC.

Scientists used an iPhone and a camera lens to diagnose intestinal worms in rural Tanzania, a breakthrough that could help doctors treat patients infected with the parasites, a study said on Tuesday.

Research published by the American Journal of Tropical Medicine and Hygiene showed that it is possible to fashion a low-cost field microscope using an iPhone, double-sided tape, a flashlight, ordinary laboratory slides and an $8 cameral lens.