The Week in Space and Physics
Igniting nuclear fusion, the future of American astronomy, a fight for the Moon and the hunt for exomoons.
For the briefest of moments, the experiment outshone every power station in the world - combined. It reached, almost unbelievably, a peak output of ten quadrillion watts. Yet brief it indeed was, for less than one billionth of a second later it was all over, nothing more than a rapidly cooling surge of energy..
Nevertheless, the experiment has been hailed as a milestone on the road to successful nuclear fusion. Some went so far as to label it an “historic breakthrough”, one which ushers in a new age of clean and limitless energy. Those claims should be treated carefully. Fusion is still decades from any practical implementation.
The experiment in question took place at the Lawrence Livermore National Laboratory, and involved a device known as the National Ignition Facility. This is, essentially, a massive laser, one of the most powerful on Earth. Researchers focus that laser on a tiny pellet of hydrogen fuel, and then emit an intense beam of light.
That flash of light lasts mere fractions of a second, but it is powerful enough to utterly destroy the pellet. The surface layers rapidly heat and then explode, placing an immense pressure on the layers below. If scientists get everything right, the hydrogen atoms within are forced together at such speed that they fuse - releasing a surge of energy.
This, at least, is the theory. When the facility opened in 2009, scientists predicted that success would come quickly. Computer models had proven the viability of the approach, and calculation suggested far more energy should come out than the lasers put in. All that was needed, they thought, were a few demonstration runs to prove the technique in practice.
Disappointment followed, however. The experiment failed to reach ignition - the point at which the reaction gives out more energy than is put in, thus making it self-sustaining. Indeed, the facility was barely producing any energy at all, raising questions about the large amounts of cash - billions of dollars - that the experiments cost.
The results announced earlier this month show that the National Ignition Facility may finally be approaching ignition - even if that leaves them far short of their original lofty goals. That is the result of years of careful study and tinkering to improve results - efforts which finally seem to be paying off. The most recent experimental run released eight times more energy than was achieved a few months ago.
Scientists will now study the results of the experiment, and prepare for another attempt in the next few months. If all goes well, that could bring the first sustained and controlled fusion reaction, finally demonstrating a long-sought technology. That really would be a breakthrough.
Astronomy’s Ten Year Plan
Every ten years, American astronomers take a close look at their field. The result is a detailed report outlining their main priorities for the following decade. These Decadal Surveys, as they are known, are immensely influential. Based on their recommendations a major telescope may be built or abandoned, an area of research given a boost or left to flounder, a scientific career made or broken.
Work on the most recent decadal survey started back in 2018, with astronomers hoping to publish it by Spring 2021. The coronavirus pandemic, naturally, delayed things, and publication is now expected in the next few weeks. What might it say?
Many astronomers are anxious about the prospects for new telescopes. Recent years have seen something of a decline in American observatories, marked most dramatically by the collapse of Arecibo last year, but also seen in concern about the health of the Hubble Space Telescope and the slipping timeline for the James Webb Telescope.
Astronomers would like a new big telescope, one powerful enough to compete with observatories currently under construction by Europe and China. Two key telescopes are proposed: the Thirty Meter Telescope in Hawaii, and the Giant Magellan Telescope in Chile. Work has started on both, but funding is scarce and deadlines are receding in the future.
Either, or both, would benefit from a strong endorsement in the survey. That could see extra funds directed towards the telescopes, and a renewed focus by astronomers and engineers on getting them completed.
The report will also consider options for a new space-based telescope. With the James Webb finally expected to launch later this year, astronomers are starting to think about what might come next. Four options are being examined, with the survey expected to pick one, at most, as a recommendation.
Three of the options - LUVOIR, HabEx and Origins - would give us closer views of exoplanets, especially ones that could be habitable. HabEx in particular would focus on those worlds, searching for signs of water and oxygen. LUVOIR is perhaps the most ambitious - the design calls for the biggest mirror ever placed in space, so powerful that it could directly photograph planets in distant solar systems.
Origins, by contrast, is more conservative. As an infra-red telescope - like the James Webb - it could answer questions about how things as different as black holes and planets form. That means it could be the most useful, if, as it involves little new technology, the least exciting.
The fourth option, Lynx, would look for energetic x-rays coming from deep space. Those rays often come from black holes, a prime target for study by the telescope. But another telescope, under construction by ESA, may do the same, with roughly equal power. That could make it a less tempting prospect for the report’s authors.
For a more detailed look the Decadal Survey, and hopes and fears it raises among astronomers, take a look at this article in Scientific American.
Will Musk Beat NASA to the Moon?
Another week, another delay to the Moon program. Last week space suits got the blame; this week it is Jeffrey Bezos, Amazon founder and Blue Origin CEO. At question are contracts and funding for the Human Landing System, NASA’s term for the next generation Moon Lander.
Earlier this year NASA awarded those contracts to SpaceX, after a bidding process involving three teams led by SpaceX, Dynetics and Blue Origin. NASA originally planned to award two sets of contracts but, after receiving less money from Congress than anticipated, ended up approving just one of the three proposals.
Blue Origin cried foul, arguing the change in rules was unfair. They appealed the decision to the Government Accountability Office, hoping that the decision would be overturned, and, presumably, awarded to Blue Origin instead. When that appeal was rejected, Jeff Bezos then came out with a starkly better offer to NASA.
Since that offer seems to have been ignored, Blue Origin are now extending their legal campaign by suing NASA in court. In response, NASA have paused work on the Human Lander System. This pause, coming on top of the previous delay while Blue Origin appealed, makes hitting NASA’s 2024 (or perhaps 2025) target unlikely.
Could that mean SpaceX and Elon Musk decide to go it alone? In a brief tweet, Musk hinted that he believes SpaceX will be capable of reaching the Moon even sooner than 2024. The company already has a powerful rocket - the Falcon Heavy - and an even more powerful one under construction. If they can perfect a lunar lander - with or without funding from NASA - they may be capable of running an entirely private mission to the Moon.
Musk probably already has the ability to send a crew to orbit the Moon, and has reportedly already sold tickets to do so. With Starship he may also soon have the ability to land there too, though years of testing will certainly be needed to confirm it is safe for astronauts.
Neither Musk nor NASA will be ready for a Moon landing in 2024 then. But don’t rule out the possibility that Musk sends astronauts there by the end of the decade, whether or not NASA, and Jeff Bezos, comes along for the ride.
A Galaxy Full of Moons?
Our Solar System is full of moons, more than two hundred at the last count. It stands to reason, then, that other solar systems should be equally full of moons. And yet, despite finding thousands of planets in our galaxy, astronomers have found startling few moons.
That’s mostly because moons are hard to spot. We still haven’t found all of the moons of Jupiter and Saturn, though most of the remaining ones are probably small chunks of rock. Finding moons, however big they are, around planets light years from Earth is even harder.
That’s disappointing, because moons could be some of the more habitable places around. Astronomers are deeply intrigued by worlds like Europa, Titan and Enceladus. These moons are probably habitable, at least to primitive life forms, though whether any actually exist is unknown.
Moons in other parts of the galaxy should be equally, or perhaps even more, habitable. If we could reliably see them, then, we may rapidly expand our list of potentially inhabited star systems.
Though astronomers still haven’t discovered any certain candidates for exo-moons, they did recently find a moon in the process of forming. The solar system in question appears to be young, and may resemble our own solar system as it was billions of years ago.
Around the parent star, glowing rings of debris can be seen. Those rings are gradually coalescing into planets - a process that we’ve seen occurring around several stars. But in this star system astronomers were able to photograph the disk in enough detail to spot an even smaller ring of debris.
That appears to be a moon, or perhaps several, forming around a young planet. Though the ring of debris in question appears as just a few pixels, it is probably the first definite proof of moons outside our own solar system.
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