The Week in Space and Physics: The Great Gamma Ray Burst of 2022

On the brightest gamma ray burst since the dawn of civilization, Japan's future moon walkers, Europe's oft delayed plans for Mars and Peter Higgs

Hubble spies a newborn star shining behind a cocoon of dust. Image credit: NASA, ESA, and K. Stapelfeldt (NASA JPL); Image Processing: Gladys Kober (NASA/Catholic University of America)

On October 8, 2022 a sudden wave of energy crashed over Voyager I, momentarily lit up its sensors, and then faded away. Nineteen hours later the same wave reached the orbits of Earth and Mars, swept across two dozen telescopes, and carried on, vanishing into the icy depths of space.

Astronomers soon realised the wave had been remarkably powerful. Telescopes designed to hunt for bursts of this kind were blinded by its intensity. Many others registered the surge of energy, including a Mercury-bound probe and two satellites orbiting Mars. Even the Earth’s atmosphere had changed in response, as electrons were suddenly stripped from their atoms.

Analysis showed the wave had originated some two billion light years away, and that it had come in the form of a gamma ray burst. Such bursts are actually quite common. Telescopes pick up roughly one every day, though most take place billions of light years away. Exactly what causes them is still unknown, but physicists think they are linked to dying stars collapsing into black holes.

The event of October 2022, however, broke all records. Nothing comparable to it had ever been seen before, and may never be seen again. Eric Burns, after studying past gamma ray bursts, concluded that such powerful waves arrive only once every ten thousand years. It is probably, he says, the strongest gamma ray burst to reach Earth since the dawn of human civilization.

Since then, however, there has been a lingering question about what caused it. Soon after it was spotted, astronomers pointed telescopes in the direction it came from. They saw little of interest. No supernova was seen blooming in the sky, nor were there signs of any other cosmic disaster. 

There were two reasons for this. First the burst itself took time to fade away. After the initial high energy wave, a long lasting afterglow remained and obscured the origin of the gamma ray burst for some months. Second, the burst came from behind the Milky Way, in a direction that is rich in cosmic dust and therefore hard to study.

Six months after the burst, astronomers tried looking again. This time, as a recent paper in Nature explains, they found what they were looking for. Amidst the fading afterglow were signs of a supernova - not, by any means an especially bright one, but one that could at least be to blame for the wave.

Researchers had expected to find the supernova marked by heavy elements like gold and platinum. Yet the observations found little sign of these. That suggests the supernova was not particularly powerful, and so the strength of the burst must have come from some other process. Whatever that was, for now it remains a mystery.

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Japanese Astronauts on the Moon

America will put a Japanese astronaut on the Moon, according to an announcement by President Joe Biden and Prime Minister Kishida Fumio. The voyage will take place as part of the Artemis program, America’s effort to return to the lunar surface after more than half a century of absence.

In return, Japan will build and supply a pressurised rover for use on the Moon. Since the rover will provide life support capabilities, it should allow astronauts to make long journeys across the lunar terrain. NASA is already planning for future explorers to spend up to thirty days on the Moon, and such a vehicle would greatly expand the area they can study during those stays.

As always, the timing of Artemis missions is hard to judge. At present, NASA is expecting to launch the second Artemis mission late next year, during which astronauts will fly around the Moon without trying to land. Artemis III - and the first landing - will follow in 2026. Subsequent landings might take place in 2028 and 2030.

Undoubtedly, however, this schedule is too ambitious. NASA is hoping to use SpaceX’s Starship as a lunar lander, but it is unlikely to be ready in time. Even if it is, the agency also lacks spacesuits for the crew to wear on the surface. 

A more likely scenario, then, is for the first landing to be delayed until Artemis IV flies in 2028. Japan will almost certainly have to wait until 2030 or later to get their landing. And that - since China wants to put its astronauts on the Moon in the early 2030s - means they may not be the first non-Americans to walk on the Moon.

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ExoMars

Europe’s ExoMars mission has a long and painful history. Originally dreamed up in 2001, the project was supposed to put a rover on Mars by the end of that decade. Four years later the project was officially approved, but progressed slowly until 2009 when Europe signed agreements with NASA and Russia to cooperate on Martian exploration.

After budget cuts forced NASA to pull out a few years later, Europe decided the project would go ahead as a joint European-Russian mission. Arrival on Mars was postponed to 2018, and then to 2020, and then again - partly thanks to the coronavirus pandemic - to 2022.

Russia’s invasion of Ukraine, however, put the project in limbo. Europe’s space agency, ESA, cut all ties with Russia and left ExoMars without a launcher. Even worse, many of the instruments and components onboard were Russian made, and would need replacing before the mission could go ahead.

Now, two years later, ExoMars finally seems to be moving again. ESA has awarded contracts to replace the Russian components. NASA seems to be back onboard too - the agency has agreed to supply some parts and will provide a launch vehicle. Lift-off, this time, is scheduled for 2028.

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Peter Higgs

Peter Higgs, the theoretical physicist and Nobel laureate, died last week at the age of 94. Higgs is, of course, best known for his prediction of the Higgs Boson in 1964. Together with two other phenomena - the Higgs Field and Higgs Mechanism - this boson explains why some subatomic particles have mass.

Although Higgs’ ideas were initially met with skepticism, attitudes changed when they proved key to unifying the electromagnetic and weak forces. The resulting electroweak theory formed a cornerstone of the standard model, and so placed the Higgs Boson at the centre of modern particle physics.

That left, of course, the problem of actually detecting the particle. Throughout the latter half of the twentieth century, experiments found every particle predicted by the standard model, with the sole exception of the Higgs. Only with the arrival of the Large Hadron Collider, the highest energy particle collider ever built, did physicists finally confirm its existence in 2012.

That discovery was rightly hailed as a triumph of modern physics. In little more than a century humanity had gone from discovering the quantum world to unveiling its innermost workings. Physicists, guided by mathematics and ideas of elegance, had succeeded in formulating a theory that contained within its grasp a multitude of particles and three of the four fundamental forces of nature. This accomplishment, surely, must rank amongst the greatest of human history.

For Peter Higgs the discovery brought worldwide fame and, a year later, the Nobel Prize. The attention ruined his life, he later said, destroying the peaceful existence he craved. It was strange to be so recognised for three weeks' work, he went on, and - after all - it was the only original idea he’d ever really had. Higgs, of course, was selling himself short. At least it was very nice, as he said on the day his particle was discovered, to be right sometimes.