With NASA preparing to send humans to Mars in the 2030s, researchers are studying the physical effects of spending long periods in space. Now a new study by scientists at UT Southwestern shows that the heart of an astronaut who spent nearly a year aboard the International Space Station shrank, even with regular exercise, although it continued to function well.

The results were comparable with what the researchers found in a long-distance swimmer who spent nearly half a year trying to cross the Pacific Ocean.

The study, published today in Circulation, reports that astronaut Scott Kelly, now retired, lost an average of 0.74 grams—about three-tenths of an ounce—per week in the mass of his heart's left ventricle during the 340 days he spent in space, from March 27, 2015, to March 1, 2016. This occurred despite a weekly exercise regimen of six days of cycling, treadmill, or resistance work.

The sun is the most important source of energy for sustaining life on Earth, but it gives us a lot more than just light and heat. It also gives us solar storms.

Disturbances on the sun, such as coronal mass ejections produced by solar flares that emanate from active sunspot regions, can cause solar storms. Solar flares and coronal mass ejections emit vast quantities of radiation and charged particles into space.

These events can damage the Earth's communication and power infrastructures, resulting in power outages and reduced system functionality. Satellites, space stations and astronauts, aviation, GPS, power grids and more can be affected.

As our civilisation becomes more advanced, we become more vulnerable to the effects of solar storms. Now, as the sun's activity is on the increase, we need to get better at predicting solar weather.

Many people still remember the collapse of Canada's Quebec electrical grid on 13 March 1989, which lasted for nine hours and affected six million people. It caused hundreds of millions of dollars in damages and lost revenues.