Could this plane really fly from London to Sydney in four hours? The UK government thinks so

How do you get from London to Sydney in four hours? Either you sit in your Islington flat listening to Men at Work records until you start craving Vegemite sandwiches or you wait for the Skylon super plane to start making test flights. The UK government has just given a £60 million ($92.2 million) grant to Reaction Engines, a British company that is currently developing the plane, as well as its Synergetic Air-Breathing Rocket Engine (SABRE). The SABRE-powered Skylon plane would "theoretically [allow] travel anywhere on Earth in four hours or less" and bring low-cost commercial space flight to economy class passengers.

Reaction Engines has spent the past 20 years working on SABRE, a combination jet propulsion system and rocket engine that works by cooling incoming air from 1,000 degrees Celsius to to -150 C in less than 1/100th of a second. The SABRE's ultra-lightweight heat exchanger would reportedly double the limits of a jet engine, allowing the Skylon to travel at five times the speed of sound — twice as fast as the Concorde —  before it leaves the earth's atmosphere and switches to its rocket engine. Nigel Whitehead, the managing director at BAE (which just bought a 20% stake in Reaction Engines), told the BBC:

"The potential for this engine is incredible. I feel like we’re in the same position as the people who were the first to consider putting a propeller on an internal combustion engine: we understand that there are amazing possibilities but don’t fully understand what they are, as we just can’t imagine them all. It could be very high speed flight, low-cost launches to orbit or other fantastic achievements.”

But don't get in line to buy a ticket just yet. Reaction Engines has planned a full ground-based engine test for 2020, and unmanned test flights would still be another ten years away. The technology would most likely be used as a lower cost method of launching satellites before SABRE or the still-theoretical Skylon would transition into passenger planes. "It’s easier to get into space than fly to Australia because making a vehicle that is safe for passengers is more complicated by orders of magnitude,” Whitehead said.

So keep spinning "Down Under," and keep your fingers crossed. That four-hour flight might be closer than we think.