The Week in Space and Physics: Nobel Prizes
On the Nobel Prize in Physics, the birth of the Moon, Russian-American relations in space and Europa.

This year’s Nobel Prize in Physics went – appropriately enough for this newsletter – to a trio of quantum physicists. They were awarded for their work on entanglement: one of the weirdest and most disturbing areas of quantum physics, and a subject that made Einstein so uneasy he famously referred to it as “spooky action at a distance”.
Stated simply, entanglement says that two particles – for example, a pair of photons – can be bonded, or “entangled”. After, even if those particles are separated, this special bond endures. Do something to one of those particles – measure how it is spinning, for example – and the other particle will instantly change its behaviour in response. This works no matter how far apart the particles are: even if half the universe lies between the two, the change is still instantaneous.
This is odd, and especially disturbing to someone like Einstein. His theory of special relativity states, pretty clearly, that nothing can move faster than the speed of light. Yet when it comes to entanglement this ironclad law is broken: somehow one particle knows exactly what is happening to the other, without any need to wait for light to travel between the two.
This breaks with a principle known as localism: the idea that particles should only be influenced by the things around them. Einstein’s theory of relativity is built around this principle, and puts a limit - the speed of light - on how fast influences can spread. In a famous paper he, along with two other physicists, argued that entanglement thus creates a paradox at the heart of physics.
Einstein tried to salvage things by arguing that quantum physics was incomplete. Underneath it all, he was convinced, was a better behaved theory; one that kept localism intact. This became known as “hidden-variable theory”: the idea that the change in behaviour was predetermined all along, yet invisible and unknowable to us.
In the 1960s John Stewart Bell, a physicist, devised a way to test this idea. The Nobel Prize winners carried out ever stricter versions of this test, proving, in each case, that no local hidden variables were present. Localism, it seems, is well and truly dead. Fortunately relativity could be saved: entanglement, despite its instantaneous nature, does not allow faster-than-light travel or communication.
The implications of this are deep. It shows, most importantly, that quantum physics is indeed real. The fundamental randomness and uncertainty it describes are actual features of the universe, not simply a lack of knowledge on our behalf. It probably, too, tells us something profound about the nature of reality - but quite what is still up for debate.
All these discoveries, mysterious as they are, hold promise for the coming age of quantum computing. Entanglement has already been used to build simple quantum computers. One day it will allow for quantum approaches to encrypting data: ushering in new ways of manipulating and protecting data. Entanglement is, indeed, deeply spooky. But Einstein was wrong: it is how reality works.
For a more complete explanation, see the description of entanglement, the experiments, and the contributions of the prize winners released alongside the Nobel announcement.
The Moon’s Violent Birth
The Moon, we believe, was born in a moment of cataclysmic disaster. A small planet, roughly the size of Mars, smashed into the early Earth; ripping both apart and expelling a vast cloud of molten debris into space. Over time, the story runs, this debris coalesced; forming the familiar Earth and Moon we see today.
A new simulation of this impact suggests the Moon could have formed rapidly: within a few hours of the impact, at most. It sees the early Earth stuck a glancing blow, an impact that shatters the planet and throws out two enormous blobs of debris. The larger, and closer, of these blobs rapidly falls back to Earth, merging with the planet. Yet the second survives, and remains in orbit around the Earth. Over time it cools, gradually solidifying until it becomes the familiar Moon we see today.
Older theories told a slightly different version of events. They usually imagine the second planet – sometimes named Theia – shattering as it strikes the Earth. Most of it ends up in orbit, gradually coming together to form the Moon over a period of months or years. Yet this idea, if true, would mean the Moon and Earth end up with different rocks: most of the Moon would be made of Theia, not Earth.
Studies of Moon rocks contradict this. They show the Earth and Moon are made of almost the same things, most likely a mixture of material from both the early Earth and Theia. Other questions linger: the Moon’s tilted orbit is hard to explain with the older theories, as is its thin crust.
The new model neatly resolves all three problems. It shows the Earth and Theia mixing more thoroughly, explaining why the Moon and Earth now have the same rocks. It suggests the core of the Moon formed from a large chunk of rock that survived the collision mostly intact, with a thin crust forming on top. And it also allows the Moon – or the blob that eventually became the Moon – to start out on a wider and more tilted orbit, thus explaining its movements today.
Russia Adopts a New Approach to Space
For the first time in two decades, a Russia cosmonaut last week travelled to the International Space Station on an American spacecraft. The launch of Anna Kikina, Russia’s only female cosmonaut, is a notable reversal of roles between Russia and America. For almost a decade, between 2011 and 2020, America was forced to rely on Russia to carry its astronauts into orbit.
More remarkably, the trip also marks a rare cooperation between the United States and Russia at a time of high geopolitical tension. It signals a friendlier stance from the Russians on the space station. Yuri Borisov, the new head of Roscosmos, seems to be trying to repair the damage done by his predecessor Dmitry Rogozin.
Under Rogozin, Russia often threatened to pull out of the space station, at one point suggesting it might crash back to Earth without his help. Yet these threats were little more than words. Russia’s cooperation with America and Europe quietly continued in the background. Under Borisov, however, Russia seems more openly committed to cooperation.
Roscosmos and NASA have already agreed four more launches that will see American astronauts launch on Russian rockets, or vice versa. Reports also suggest Russia wants to extend the Space Station partnership beyond 2024, in sharp contrast to past fears Russia would soon pull out.
All this may be an acknowledgement that the Russian space program has few other good alternatives. Despite Russia’s frequent allusions to a planned station of their own, there is no sign of actual progress towards building one. For better or worse, then, it seems space will remain a rare bright spot in American and Russian relations.
Juno Images Europa
NASA’s Juno spacecraft flew over the surface of Europa, one of Jupiter’s largest moons, earlier this month. As it did, it captured the closest pictures of the world taken in several decades; revealing new details of its icy surface.
Europa is one of the more fascinating moons in the Solar System. Scientists speculate it is heated by Jupiter’s tremendous gravity. That heat could have created a vast and warm ocean under its frozen surface.
Though Juno is currently the only spacecraft visiting Jupiter, two new missions will head towards the giant planet and its moons in the next few years. JUICE, a mission funded by the European Space Agency, will focus its attentions on Ganymede, the largest of Jupiter’s moons. NASA, meanwhile, will send the Europa Clipper, which as the name suggests, will spend much of its time investigating Europa.