Orbits explained: It's hard to get into space -- but great once you're there

Orbits explained: It's hard to get into space -- but great once you're there

Space is closer than you might think -- about 62 miles up, only a little farther away from you than San Jose is from San Francisco. Heck, you can get halfway to space in a balloon.

The hardest part about space, it turns out, isn't so much getting there as staying there. That's where the idea of orbiting comes into play. Once you accomplish the hard work of getting a spacecraft into orbit, you can get years of use out of it as it loops more or less effortlessly around the planet on its own invisible track.

Orbits are "roadways in space," said Ajmal Yousuff, a Drexel University professor who studies aerospace vehicles. "You place a vehicle in space, and it stays there."

 GM and Nikola agree to massively scaled back deal

GM and Nikola agree to massively scaled back deal

General Motors and Nikola announced a watered-down memorandum of understanding for a new partnership after months of discussions Monday, but the details remain foggy. With the new agreement, GM said it will supply its Hydrotec fuel cell systems for Nikola's upcoming fuel cell semi trucks. The question remains: Why does Nikola need GM's tech if it supposedly already developed proprietary systems?

I digress because what's not included in this MOU is even more interesting. The big news is GM decided not to build the Nikola Badger. We previously covered the vehicle's hyped-up birth and not-so-surprising demise: Without GM to build and engineer the truck, Nikola called it quits.

How to 'disappear' on Happiness Avenue in Beijing

How to 'disappear' on Happiness Avenue in Beijing

On a busy Monday afternoon in late October, a line of people in reflective vests stood on Happiness Avenue, in downtown Beijing.

Moving slowly and carefully along the pavement, some crouched, others tilted their heads towards the ground, as curious onlookers snapped photos.

It was a performance staged by the artist Deng Yufeng, who was trying to demonstrate how difficult it was to dodge CCTV cameras in the Chinese capital.

As governments and companies around the world boost their investments in security networks, hundreds of millions more surveillance cameras are expected to be installed in 2021 - and most of them will be in China, according to industry analysts IHS Markit.

Coronavirus: Second-hand car website becomes latest 'unicorn'

Coronavirus: Second-hand car website becomes latest 'unicorn'

A second-hand car website has seen its value rocket to more than $1bn (£750m), putting it into unicorn status.

India's Cars24 has seen a big rise in business during the pandemic as people look to alternatives to public transport such as pre-owned cars.

India's popular but unreliable rail networks were shut off completely when the country went into lock-down.

A unicorn refers to a privately-owned start-up firm that is now valued at more than $1bn.

Other start-ups that have gone on to become unicorns, and household names, include Uber and Airbnb.

How machine learning is allowing thousands of students to sit exams at home

How machine learning is allowing thousands of students to sit exams at home

The phones began ringing off the hook at Piero Tintori's company Better Examinations back in April.

His tech business allows tens of thousands of students to remotely sit exams at the same time, with each needing just a laptop, a webcam and an internet connection.

The firm's software uses machine learning (ML), an advanced form of artificial intelligence, to detect patterns in user behaviour that could indicate attempts to cheat. Its technology can also automatically mark multiple-choice answers and mathematics exams.

In addition, it checks each exam-sitter's identity using the webcam, to ensure that no-one else is sitting the test for them. The Better Examinations program also temporarily restricts access to the internet, or certain websites and applications on each person's computer.

"We had 60 organisations from all over the world contact us out of the blue, who wanted to run exams online in May and June," says Mr Tintori. "Everything from universities, to professional organisations, to schools."