Our office recently started recycling glass. Most of the collection centers I've found in Hong Kong do not take glass. And while my apartment building has signs warning residents not to throw trash out of their windows, there are none urging them to save the Earth and recycle. It's definitely different from the U.S., where some cities collect plastic, paper and glass curbside. And it's a far cry from Japan, where recycling is a law.
Countries vary in their approaches to waste management on Earth. But when it comes to trash in space, there is international consensus that it's an important problem. A near miss between the International Space Station and an unknown piece of debris has drawn renewed attention to the growing danger.
Usually ISS can dodge orbiting space junk, but this was spotted too late. Instead, the six-member ISS crew had to seek shelter in the Soyuz capsules docked to the station. NASA estimates the object passed about 335 meters from ISS. That's believed to be the closest encounter ever.
This is only the second time that a space station crew has taken shelter in the Soyuz. The first was in March 2009, when a bit of satellite rocket motor flew close by.
That incident happened one month after a defunct Russian satellite accidentally collided with a U.S. satellite. NASA says that created more than 2,000 trackable bits of debris.
So just how much trash is up there? Take a look.
This graphic represents the space junk floating in "Low Earth Orbit." That's the region of space within 2,000 kilometers above Earth. But most of the debris is in an altitude above where the shuttle and space station orbit.
The U.S. is currently tracking 8,000 objects 10 cm in diameter (about the size of an orange) or larger. Approximately 500,000 particles are between 10 cm and 1 cm (roughly the size of a marble). Millions more are even smaller.
Keep in mind these items are whizzing by at about 10-kilometers a second. NASA says even tiny paint flecks can do damage to spacecraft at that speed. Or to put it another way, if something the size of a marble hit you in space, it would be like a bowling ball slamming into you at 520-kilometers an hour on Earth. That's why astronauts wear multiple layers of protection to keep from getting hurt on spacewalks.
NASA says ISS is the most heavily shielded spacecraft ever, so it can take the impact of smaller pieces of debris. But there are ever more bits flying around. And what goes up doesn't always come down. They can remain in orbit for a century or more above 1,000 km.
Clean up is a challenge. It's technically tough to rendezvous with space junk and quite costly. So what can we do? NASA says the best solution is prevention.