The Week in Space and Physics
A new radio telescope, power from space, sub-orbital tourism takes off and the rise of the machines.
Back in the 1930s, an engineer working on trans-Atlantic radio systems noticed an odd daily pattern appearing in his radio signals. Investigation showed this repeating signal came not from Earth, or even from our Solar System, but from the heart of the Milky Way.
The engineer, Karl Jansky, was soon reassigned to more profitable activities. Still, his chance discovery inspired astronomers to take a closer look at radio signals coming from the heavens. Over the following decades the field blossomed, revealing many surprises - from pulsars to quasars. Today it is one of the main areas of astronomical research.
Jansky’s signal, it turned out, was caused by the powerful black hole at the centre of our galaxy. Such extreme objects are intense emitters of radio waves. Indeed, it is through radio observations that we get some of our best views of black holes - including the famous first image taken in 2019.
Little wonder, then, that astronomers are keen to build more powerful radio telescopes. The Square Kilometre Array - a proposed telescope fifty times more sensitive than any other built - is one such idea. Stretching across Australia and South Africa, the observatory would combine thousands of antennas into a single virtual telescope of unprecedented strength.
After years of talks, designs and redesigns, project leaders finally signed off on the observatory last week. Contracts for the construction should be prepared over the next few months, with building starting in earnest early next year. Don’t expect results anytime soon - even if all goes to plan the telescope will not begin operations until 2028. After that, though, astronomers are planning at least half a century of observations.
The web of communications satellites now encircling the planet may threaten those plans. Players like Starlink and OneWeb are placing thousands of new satellites in orbit, each firing radio signals at the Earth. For the Square Kilometre Array, each of those satellites is a point of interference, disturbing its view of the night sky.
According to project leaders, networks like Starlink are manageable for the moment. Astronomers think that only four percent of observations would be interrupted - hardly enough to throw in the towel. Worse are the larger constellations planned for the future. Starlink could expand to include tens of thousands of satellites, as could a rival Chinese network. That would affect far more than just four percent of measurements.
The idea of placing thousands of solar panels in orbit has been around for a while. In theory the concept seems almost utopian. In space, far above the clouds, solar power is available twenty-four hours a day, regardless of the weather. Massive banks of solar panels could capture that energy, beaming it down to wherever needed.
Yet a closer inspection reveals a number of problems. Sending all that power back to Earth is hard. Some suggest using microwave links to do this, or even lasers. But the technology needed has never been demonstrated over such vast distances. Even worse, the solution demands massive and expensive infrastructure on the ground.
If that can be done, the power stations still need to be put in orbit. Calculations suggest they would be huge structures, dwarfing the largest thing so far built in space: the International Space Station. Putting all that mass into orbit, even with the most powerful rockets available today, would take unrealistically long.
Most serious analysis of the question concludes that we are decades, if not centuries, from feasible space based power. To get there we need to build up industry in space - from asteroid mining to manufacturing. With that in place, the panels could be built and maintained in orbit, with no need for expensive rocket launches. That, though, will take a long time.
China seems to think differently. According to remarks from Long Lehao, the chief designer of China’s powerful Long March rockets, the country could start building a power station in orbit as soon as next year. At first that would be a simple demonstration of the concept: perhaps proving key technologies like power collection and transfer by laser or microwave back to Earth.
Later iterations would build on that, leading up to a commercial station operating by 2050. That’s still a fair way off, but China has a history of long-term strategic thinking in space that many western space programs lack. By laying the ground work now, China may be able to reap the benefits in decades to come.
Space is fast becoming a battleground for billionaires. Three - Elon Musk, Jeff Bezos and Richard Branson - each confirmed plans to reach major milestones in July. The week began with news that SpaceX plans to attempt an orbital launch of Starship sooner rather than later. Gwynne Shotwell, SpaceX’s president, confirmed that the company would like to launch before the end of the month, if possible.
That’s ambitious, especially as SpaceX is still waiting for approval from the FAA allowing the launch to take place at all. Even so, the plans fit with SpaceX’s fast moving approach to rocket development. There’s a good chance that Starship’s first orbital flight is not entirely (or perhaps at all) successful. But be sure they will try again and again until it is.
Jeff Bezos, the billionaire founder of Amazon and owner of rocket company Blue Origin, named Wally Funk as the third passenger on a flight to the edge of space later this month. She will join Bezos and his brother, Mark, along with a so far unknown fourth crew member on the mission.
Wally Funk has a long history of involvement in the space program. In the 1960s she was one of thirteen to graduate from the “Women in Space” program, an attempt to persuade NASA to send a woman into orbit. Aged just twenty-one at the time, she passed a rigorous series of mental and physical tests, only to see the idea cancelled by NASA. Now, at the age of eighty-two, she will finally get her chance to visit space, if only for a few moments.
She and Jeff Bezos will be beaten by Richard Branson. The British billionaire will fly on 11 July, reaching an altitude of around eighty kilometres. That will make him one of the first commercial space tourists in history, ushering in a new age of space tourism.
Wally Funk and Jeff Bezos do have one thought to console themselves with. Their capsule will reach one hundred kilometres high - twenty more than Branson. That puts them across the internationally agreed boundary of space, a line Richard Branson will not cross.
A series of stories this week underlined the growing importance of artificial intelligence in physics - and perhaps provided hints that it could soon start replacing physicists altogether.
In Japan, a team trained a computer to examine observations of distant galaxies. Those are often distorted by gravitational lensing - an effect that astronomers use to measure the mass of the universe. To do that, though, they must first work out which galaxies are really distorted, and which just look a bit odd. Humans struggle to do this task accurately - but the AI system proved more than capable. Its results helped boost our current models of the universe.
A second team in Europe built a convolutional neural network - a type of machine learning - designed to examine the outer atmosphere of the Sun. From time to time cool spots known as "holes" appear in this region, directing streams of energetic particles into space.
Currently, such holes must be identified by hand. That is a long and difficult task - especially as the solar atmosphere is constantly changing. The neural network automated this process - finding almost every hole spotted by the professional astronomers.
The more astonishing breakthrough, however, was reported by Scientific American. To deal with the tough equations that quantum mechanics throws up, a group of researchers built an alogrithm that learns to solve them. To their surprise, it started suggesting unknown solutions and new experimental approaches.
That will help to speed up research at the frontiers of quantum physics, but it also offers a glimpse of a new way of doing science. Future researchers may be guided by computers coming up with promising experiments and new lines of inquiry. As the Economist speculated this week, we may even find ourselves awarding the Nobel Prize to a machine.