The Week in Space and Physics
This week: the dawn of space tourism, a new space station, what really happened to Betelgeuse, and a mysteriously vanishing star.
Private spaceflight is edging closer and closer to reality. Space tourism, of the form where billionaires pay for short trips into orbit, has been around for a while, though such trips have always relied on the support of national space agencies. Now, purely commercial flights into space - onboard a privately built and operated vehicle - are on the verge of becoming routine.
The next few weeks should see two sets of private astronauts cross the boundary to space. The first to confirm an attempt is Blue Origin, who will carry Amazon founder Jeff Bezos to the edge of space on July 20. To prove the commercial aspects of the flight, he will be joined by a so far unidentified customer. The ticket came at an extraordinary price - whoever they are, they have paid $28 million for the trip.
Rumours suggest that Virgin Galactic may try beating them to space. Richard Branson, owner of Virgin Galactic, could fly on July 4, beating Jeff Bezos by more than two weeks. No official confirmation of this plan has yet been made, though reports suggest that Virgin Galactic is still lacking the necessary regulatory approval.
Such flights only just touch the edge of space. Travellers get a few moments of weightlessness, before a short fall back to Earth. Some companies are, however, looking further. Axiom Space, an American startup, recently brokered a deal with NASA and SpaceX to send a crew of private astronauts to the International Space Station in January next year.
NASA is keen on the idea. They are now asking companies to submit proposals for two more private missions to the space station. Who else, other than Axiom Space, might be interested is not yet clear. One candidate is Space Adventures, who have already signed deals with SpaceX to send astronauts into orbit.
China’s space program continues to grow in scope and ambition. Following the successful launch of the core Tianhe module of their new Tiangong (“Heavenly Palace”) space station, China launched a crew of astronauts to take up residence.
The three astronauts, led by Commander Nie Haisheng, will spend three months living and working onboard the station. They may find it a cramped experience - the space station is still relatively small, consisting only of the Tianhe module. China plans to expand the station next year by adding two more modules. That will bring the station to roughly the size of Mir, the decommissioned Russian station.
China also revealed details about their plans for lunar exploration and about their plans to build a moonbase. Construction will start around 2026, with a series of missions to test and demonstrate capabilities in exploration, resource use and astronomy.
A decade later, in 2036, the base would be ready for human occupation. China has not yet given a target date for a first manned mission to the Moon, but, given their ambitions and abilities, it seems reasonable to expect one in the early 2030s.
Back in 2019 a series of articles breathlessly proclaimed that Betelgeuse, a nearby supergiant star, was about to explode. It didn’t, of course, and the chances that it actually would were always low. The trigger for these articles was, however, real: Betelgeuse appeared to mysteriously dim over the year.
Betelgeuse is one of the biggest nearby stars, roughly 500 light years from Earth. It is also old, as such stars go, and astronomers believe that sometime in the next few thousand years it will die in a supernova explosion. That makes for exciting headlines - but it is also true that as an old, dying star, it tends to fluctuate in brightness.
The dimming seen in 2019 and 2020 was deeper that anything seen before - though keep in mind our observations only stretch back two centuries or so, a blink of the eye in cosmic terms. That probably meant something unknown on the star was happening - something the press interpreted to mean a fiery supernova was near.
In the end, Betelgeuse started to brighten again in mid-2020, ending the speculation of a dramatic outcome. But the cause of the dimming was still of interest to astronomers, and they now think they have found the cause.
Detailed imaging of the star revealed that only one area of the star actually got darker. A recent study suggested that region of Betelgeuse cooled, thereby darkening slightly. As it did, it also cooled a cloud of gas that surrounds the dying star, creating a patch of dust that further dimmed the star, at least as seen from Earth.
What does it mean when a star vanishes, only to reappear a few months later? That’s exactly what astronomers have been trying to figure out ever since VVV-WIT-08 - the “WIT” stands for “What Is This?” - mysteriously vanished back in 2012.
The most likely explanation for this temporary disappearance is something big passing between the star and Earth. What that could be, though, is puzzling. To block out an entire star, as it did, it must be huge, far bigger than the Sun, and very dark.
In a recent paper, astronomers analysed the event and attempted to find an answer. They concluded that whatever it was, it must be a big object linked, somehow, to the disappearing star. Despite considering a number of explanations - from shattered solar systems to black holes - no one candidate could explain everything they saw.
The implied properties of the object are breathtaking, and perhaps a little scary. Something so large, roughly fifty times bigger than the Sun, would normally emit a lot of light. But this object was faint, if slightly blue. Whatever it was, it has yet to make a reappearance, though astronomers will undoubtedly be keeping an eye on VVV-WIT-08 for some time to come.
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