The Week in Space and Physics: To the Moon and Back
On Artemis I, a controversy over wormholes, the Solar System's glow and Dear Moon

Half a century ago, as they voyaged from the Earth the Moon, the astronauts onboard Apollo 17 took a photo of our planet. At the time it was little thought of; so little, indeed, that the astronauts themselves seem to have forgotten which of them took it. Perhaps there was little to be remarked on. The image, showing the sphere of the Earth bright and beautiful against the darkness of space, was neither the first such photo made, nor even the first captured by an astronaut.
Yet the image, once the astronauts had returned home, was hailed as a symbol of the Earth’s fragility and uniqueness. The Blue Marble, as it was named, is also significant in another way. It marks the last time, fifty years ago this December, that any human travelled far enough to see the full face of our planet against the void.
NASA surely had this in mind when they recently directed the Orion capsule of Artemis I to capture a photograph of the Earth and Moon together. Orion, at that point, was further from Earth than any other capsule in history; breaking the record once held by the Apollo missions. Artemis I is, of course, uncrewed, yet Artemis II - and the others to follow - will not be. Men and women, NASA hopes, will soon see the full beauty of the Earth again.
The Artemis I mission – which came to a successful end on Sunday afternoon – seems to have gone as well as NASA could have hoped. It demonstrated the power and functionality of the new SLS rocket which, despite months of delays, finally roared to life at the end of November. It also proved the operation of the Orion capsule, and, fortunately, the safety of its heat shield as it plunged back through the atmosphere.
That last step, according to NASA engineers, was crucial. Though the capsule has been to space once before – a test flight flew in 2014 – it had never re-entered at the speeds involved in a return from the Moon. When it hit the atmosphere on Sunday, Orion was travelling at over eleven kilometres – seven miles – per second; or over thirty times the speed of sound.
At such speeds the heat of re-entry is extreme. The capsule reached temperatures of more than three thousand degrees centigrade. Though Orion was built to survive these temperatures, it was impossible to fully test it on Earth before the flight. Had it failed, the results would have been catastrophic: certain destruction of Orion would have followed, with only charred wreckage falling to the ground.
Fortunately the waiting observers were treated to another view: that of Orion, with its parachutes gracefully unfurled, slowly descending towards the Pacific Ocean. NASA could hardly have asked for a better ending to the long-awaited Artemis I.
A Wormhole Controversy
The movie Interstellar is famous for its depiction of a black hole. This was no accident. The production crew enlisted renowned physicists to advise them on the science and to help them put together visual effects that created a realistic view on screens.
That effort paid off. Not only was the black hole imagery a highlight of the movie, but it also turned out to somewhat resemble the actual, far fuzzier, photograph of a black hole astronomers later captured.
Yet Interstellar also featured another cosmic object that warped space and time: a wormhole. Appearing mysteriously beyond Saturn, this strange object opened a shortcut between solar systems.
Wormholes, like black holes, were first predicted by Einstein’s theory of relativity. Theoretically, at least, they allow distant regions of the universe to become connected through a higher dimension: a trick that allows faster-than-light travel across the cosmos. Yet, unlike black holes, no hint of a real wormhole has ever been discovered.
Much attention, then, was drawn earlier this month when a team of researchers claimed to have built a wormhole in a lab. The experiment in question used Google’s quantum computer. By simulating equations on that computer, reports said, they had actually gone further: linking quantum components of the computer together in a wormhole.
If true, the news would be ground-breaking. The researchers would not only have proven the existence of wormholes and faster-than-light travel, but would have forever changed our view of space and time. Such an experiment would rightly be lauded as one of the greatest of all time.
Yet cracks in the story soon started to emerge. Experts in quantum physics regarded the results with puzzlement, noting that the experiment seemed to show little that was actually new. Indeed, as many observed, the same simulation has been performed on non-quantum computers before. The only real difference, indeed, was the “quantum” element, a factor that hardly seems enough to claim the simulation really created a wormhole.
In the end, then, it seems that wormholes are still confined to the world of theory. We may someday succeed in building one, or finding one somewhere in space, yet nothing so far suggests they are any more real than unicorns.
The Glowing Solar System
The night sky, astronomers have found, is not perfectly dark. That may seem rather obvious - the night sky is littered with stars, planets and moons. Yet a new discovery shows that the darkness between these pinpricks of light has a faint glow of its own.
On Earth this can be explained by the atmosphere, which glows slightly even at night. This effect, which is sometimes bright enough to be seen by eye, is caused by the presence of certain gas molecules in the atmosphere, and gives the entire sky a slight hue.
Yet astronomers recently found a faint glow exists even far beyond the Earth. Data from Hubble - which flies hundreds of miles above the atmosphere - spotted the light coming from every direction. It is faint - certainly invisible to the eye - but appears to be constantly present.
This cannot be explained by gas molecules, since Hubble is flying far above any that could be glowing. Instead astronomers speculate the light is coming from a hitherto unknown cloud of dust filling the Solar System.
This dust, they think, is the legacy of millions of comets falling through the Solar System. Each would have left a trail of dust and ice behind it. Since comets seem to come from every direction in the sky, this dust would have ended up uniformly spread through the inner solar system. Sunlight reflecting off this dust would thus create a ghostly glow, faintly lighting up the entire sky.
Intriguingly, another telescope flying far beyond Pluto - New Horizons - found traces of an even fainter glow coming from deep space. The origins of this remain mysterious, but it could be coming from distant galaxies, too far away for our telescopes to pick out individually. Instead, their light merges, creating a slight but uniform glow across the cosmos.
Dear Moon, When Shall We Meet?
A Japanese billionaire, Yusaku Maezawa, selected a crew of eight for a mission to fly around the Moon. The mission, which he names Dear Moon, will make use of SpaceX’s Starship, a rocket and spaceship currently under development.
Among the crew are Youtubers, DJs, photographers and actors, in keeping with Maezawa’s desire to carry artists into space with him. He hopes that the voyage to the Moon, along with the responsibility he believes comes with such a journey, will inspire the crew to create visionary artwork.
Quite when the trip will happen looks uncertain. Publicly the mission is scheduled for 2023; but as Starship is far from ready, it looks likely to be postponed for at least a few years more. SpaceX have been preparing to test Starship for more than a year, and according to recent reports, that test is unlikely to come before spring next year. Several more flights will be needed before it can carry astronauts, and before it can head further from Earth.