POP GOES THE SPACE JUNK: There's a lot of junk up in space that's a danger to spacecraft and space missions. That's why most of it is being carefully tracked by the sensitive Murchison Widefield Array radio telescope in Australia. The telescope array of 2,048 dual-polarization dipole antennas arranged in 128 formations of four-by-four tiles can detect objects smaller than 1 metre. One technique it's using is to pick up pop music from FM stations reflected back by objects up to 1,000 Km away. Way to make pop useful.

WITH A LITTLE BIT OF LUCK: Chernobyl is famous for its massive radiation leak nearly 30 years ago. At the time the site was covered in concrete and metal to help contain the radioactivity, but that cap is deteriorating. Now work is underway to cover the whole lot with a massive 29,000 ton metal arch whose ends will be sealed.

The site is still so radioactive the arch is being built 300 metres away and will slide into place along rails. But that's only after the old reactor chimney has been dismantled. Workers on that job can receive a year's worth of maximum radiation exposure in just a few hours. The project is due to be completed in 2015. With any luck no-one will make any mistakes that release vast amounts of radiation into the atmosphere.

LET THE SUN SHINE ON: Solar panels are a wonderful thing, but like ordinary windows on a house they accumulate dirt over time, reducing their efficiency. Sinfonia's robot cleaner moves from panel to panel, eradicating dirt and debris with a spinning scrub brush and squeegee combination, along with a reservoir of detergent. It can clean more than 93 square metres every hour and can crawl across a gap from one panel to another to finish the job. The cleaner runs on a battery that must be recharged from time to time. One of the panels at the end of a row should be its home base and able to recharge the device.

LIFE ON THE OCEAN WAVE: The Freedom Ship is a concept of a place to live, work, retire, vacation, or visit. The idea is to create a mobile community, circling the globe once every 3 years. Commuter aircraft would ferry residents and visitors to and from shore, making use of the top deck as an airport. The concept has the ship at 4,152 metres long, 228 metres wide, and 106 metres high. Imagine the building consent process for making structural changes to your living or working quarters.

CAST A LITTLE LIGHT: A camera generally works by recording photons reflected from objects. The more light reflected, the brighter the object. A team at MIT are working on recording only a single reflected photon from positions on a grid. It keeps firing until a photon is reflected and then moves on. A light surface should require fewer bursts of photons than a dark surface. Apply a clever algorithm and you can use this to record images in very low light, perhaps producing images from only one nine-hundredth the light. The technique could be useful for studying biological systems where too much light could be damaging, or for stealth imaging. Timing matters.

Miraz Jordan, knowit.co.nz