When a massive star dies, first there is a supernova explosion.

China launched Tianhe-1, the first and main module of a permanent orbiting space station called Tiangong (Heavenly Palace 天 宫), on April 29. Two additional science modules (Wentian and Mengtian) will follow in 2022 in a series of missions that will complete the station and allow it to start operations.

While the station is not China's first—the country has already launched two—the modular design is new. It replicates the International Space Station (ISS), from which China was excluded.

There are many reasons for China to invest in this costly and technologically challenging project. One is to conduct scientific research and make medical, environmental and technological discoveries. But there are also other possible motivations, such as commercial gains and prestige.

That said, Tiangong does not aim to compete with the ISS. The Chinese station will be smaller and similar in design and size to the former Soviet Mir space station, meaning it will have limited capacity for astronauts (three versus six on ISS).

If asked where meteorites come from, you might reply "from comets." But according to our new research, which tracked hundreds of fireballs on their journey through the Australian skies, you would be wrong.

In fact, it is very likely that all meteorites—space rocks that make it all the way to Earth—come not from icy comets but from rocky asteroids. Our new study found that even those meteorites with trajectories that look like they arrived from much farther afield are in fact from asteroids that simply got knocked into strange orbits.

Your smartphone may be able to sense space weather and even get a little disoriented by it, according to researchers, who tested how geomagnetic storms affect the magnetic sensors in cell phones. The new research suggests that apps being developed to use cell phone magnetometers to pinpoint locations could be susceptible to space weather errors. On the other hand, millions of phones sensing changes in Earth's magnetic field could potentially create a vast observatory to help scientists understand these geomagnetic storms.

Cell phone magnetometer chips are being explored as a backup for GPS, which uses satellite signals to triangulate location and thus is often inaccurate or unavailable in places where signals can't penetrate, such as inside large buildings or underground.

"Smartphone magnetometers are being commercially explored for applications as diverse as locating customers in shopping malls for targeted advertising, to precision needle-guided surgery," wrote Sten Odenwald, of NASA's Space Science Education Consortium at Goddard Space Flight Center in Maryland, in Space Weather.

This weekend, a Chinese rocket booster, weighing nearly 23 tons, came rushing back to Earth after spending more than a week in space—the result of what some critics, including NASA Administrator Bill Nelson, have attributed to poor planning by China. Pieces of the rocket, dubbed Long March 5B, are believed to have splashed down in the Indian Ocean near the Maldives, and no one was injured.

But the event has shown the potential dangers that come from humanity's expanding presence in space, said Hanspeter Schaub, professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences.

Schaub is an engineer with an eye for the myriad bits of junk that circle our planet—from meteors the size of grains of dust to manmade rocket stages as big as school buses. As humans launch more objects into space, he said, this debris may increasingly threaten the safety of satellites and human astronauts in orbit. In 2009, a decommissioned Russian satellite crashed into an active satellite called Iridium 33, sending a cloud of shrapnel hurtling around the planet.