A study of astronauts' eyes and brains shows that they are affected after a long space stint.

This includes flattening of the rear of the eyeball, bulging of the optic nerve and changes in the pituitary gland and its connection to the brain, according to University of Texas Medical School, Houston researchers.

Researchers performed Magnetic Resonance Imaging (MRI) and analyzed the data on 27 astronauts, each of whom were exposed to microgravity, or zero gravity, for an average of 108 days.

Eight of the 27 astronauts underwent a second MRI exam after a second space mission that lasted an average of 39 days, the journal Radiology reports.

"The MRI findings revealed various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity," said Larry A. Kramer, professor of diagnostic and interventional imaging at the Texas Medical School, according to a statement.

Findings included expansion of the cerebral spinal fluid space surrounding the optic nerve in nine of the 27 astronauts.

Flattening of the rear of the eyeball was found in six (22 percent), bulging of the optic nerve in four (15 percent) and changes in the pituitary gland and its connection to the brain in three (11 percent) of the astronauts.

"These changes that occur during exposure to microgravity may help scientists to better understand the mechanisms responsible for intracranial hypertension (buildup of pressure within the skull), in non-space travelling patients," concluded Kramer.

Space travel could thrill but also kill
Sydney (IANS) Mar 13 - Space travel could be the ultimate in human adventure but there's a catch - it could thrill but also kill and destroy everything within sight.

It could create the ultimate 'killer entrance', devastating your destination and anything around the landing craft, according to calculations by Geraint Lewis and two honours students from the University of Sydney.

The Sydney team is the first to spell out on the effects of theoretical space travel using an Alcubierre warp drive, the journal Physical Review D reports.

Miguel Alcubierre, Mexican physicist, proposed this warp drive in 1994 as a way to travel faster than light, overcoming the limit on particles travelling at such speeds posed by Einstein's theory of special relativity, according to a Sydney statement.

"When the spacecraft decelerates to stop at its destination, the particles collected at the front of the spacecraft are released with such high-energy that they would destroy anything they came in contact with," said Lewis, professor from the Sydney School of Physics.

"During the journey the particles picked up and included inside the bubble could threaten the safety of people travelling in the spacecraft," added Lewis.

"What we've shown is that when this spacecraft decelerated to arrive at its destination, it would release high energy particles which would destroy anything near the spacecraft's landing spot," concluded Lewis.

Source: Indo-Asia News Service