The Week in Space and Physics: Ancient Galaxies
The Week in Space and Physics: Ancient Galaxies
On vast ancient galaxies, Dragon and Starliner, Zhurong and a new Soyuz for the Space Station
They don’t, if we’re honest, look like anything much at all. Each is no more than a dot, glowing red against a noisy black background. At first glance, indeed, your eye would probably skip right over them, drawn instead to brighter, more impressive splashes of light.
Yet these six dots, captured in one of the deepest views ever observed by the James Webb Space Telescope, are remarkable. For one thing, astronomers believe they are galaxies seen six hundred million years after the Big Bang, making them some of the oldest objects ever sighted. For another, they appear to be extraordinarily large: far larger than our understanding of physics should allow.
That last point could have deep implications for astronomy. If the dots turn out to be as large as they look, then they threaten to blow a gaping hole in cosmological theory; forcing us to rethink the story of how the modern universe came to be. In doing so, they could change the way we think of dark matter and dark energy, of the big bang and the early universe, and ultimately open the door to a radically new understanding of the cosmos. No wonder one of the researchers that found the dots labelled them “universe breakers”.
This, of course, is a big ask; especially of six faint dots seen in a photograph. Yet these dots also represent our first view of an era that had previously been confined to modelling and simulation. Telescopes, until the James Webb come along, had found it impossible to peer back so far, leaving the period when the first galaxies came together shrouded in darkness.
Astronomers attempted to fill that darkness with models, especially with one known as Lambda-CDM. This model, when input into a computer and correctly configured, can simulate the evolution of the universe from the Big Bang until the modern day (or, if you like, well into the future). It has proven remarkably successful, creating simulated universes that look fairly similar to one we actually live in.
That had given astronomers a great deal of faith in it, especially as it predicted amounts of dark matter and dark energy that seemed in agreement with other observations. Yet it also predicts how the cosmos should have looked early on, when the first galaxies came together. Importantly, it places limits on how fast those galaxies should have grown.
These six dots, however, appear to show galaxies far larger than Lambda-CDM allows. Either the model is wrong, therefore, or these dots are not what they appear to be. Both options are possible, of course, but for now the focus is on the latter. The observations are early, based on limited data. They may be mistaken. They may, indeed, not even be galaxies at all.
To find out more, astronomers will need more data. The James Webb is sure to spend more time examining each of these six dots in detail. Researchers are especially keen to measure the spectra of light coming from them; data that should show what they are made of. That should help settle the question of what they are and how old they are.
Should they turn out to be as old and as big as they appear, then Lambda-CDM is in trouble. With it, so too is our understanding of how the modern universe came to be. The James Webb is already shaking modern cosmology. A few more red dots may be enough to overthrow it completely.
As Dragon Stumbles, Starliner Readies for Launch
SpaceX scrubbed an effort to send astronauts to the International Space Station on Monday. The launch, which was abandoned two minutes before lift-off, would have been SpaceX’s eighth crewed flight to the station, and ninth crewed mission overall.
At fault seems to have been the rocket’s ignition system, which handles the delicate step of lighting its powerful engines. Engineers, according to NASA, were unable to confirm that the ignition fluid had been fully loaded. Out of precaution, therefore, they chose to postpone the launch until later in the week.
SpaceX has by now flown eight crews of astronauts to the space station. Yet NASA has long planned for a second company, Boeing, to do the same. That should ensure redundancy - in case of a problem with one system, for example, NASA would have an alternative available. Yet it also encourages competition and, theoretically at least, lower prices for human spaceflight.
Boeing’s capsule, Starliner, has, however, been beset by a series of problems. The worst of these came at the end of 2019, when Boeing conducted a test flight. Starliner was supposed to fly to the space station, dock, and then return safely to Earth. In the event, however, Starliner never reached the station. An error in the capsule’s onboard software caused engines to fire early, leaving it in the wrong orbit and draining its fuel tanks.
After addressing those software bugs, as well as dozens of other identified issues, Boeing tried again in May last year. This time the flight went well, docking successfully at the station and eventually landing back on Earth. As a final step before beginning regular flights, NASA and Boeing now plan to conduct a crewed test flight.
This has been tentatively scheduled for mid-April this year, a date that NASA recently said is still on track. Only one major issue - related to the capsule´s thrusters - is still outstanding, and Boeing may begin fuelling Starliner in preparation for launch in the coming weeks. If all goes according to plan, America may well soon have two human-rated space vehicles in use for the first time in decades.
Zhurong in Trouble?
In May 2021 China landed its first rover on the surface of Mars, becoming only the second nation to achieve this feat. The subsequent mission appears to have been fairly successful. Zhurong, as the rover is named, has survived far beyond the initial three months planners had hoped for.
Yet when the Martian winter arrived last May, controllers sent Zhurong into a protected hibernation mode. That should have come to an end in December, when a timed command ought to have woken the rover up. Reports, however, suggest that didn’t happen. Images taken by NASA’s reconnaissance orbiter show no sign that the rover has moved in the past few months.
Official reports are silent on the matter, but some observers speculate that the rover is having trouble charging its batteries. Dust may have accumulated on its solar panels, blocking out the Sun’s energy. Temperatures around Zhurong are also still lower than expected, potentially making it harder for the rover to awaken.
China also has an orbiter, Tianwen-1, around Mars. That spacecraft arrived along with Zhurong in 2021 and has since spent its time mapping and observing the planet’s surface. Despite some speculation that Tianwen is also suffering technical problems, China’s media recently published articles celebrating the second anniversary of its arrival on Mars. Later this year, they say, Tianwen will experiment with aerobraking; a technique that uses Mars’ thin atmosphere to control the orbit of a spacecraft.
A New Soyuz at the Space Station
Two months ago, the Russian Soyuz capsule docked to the International Space Station sprung a leak. The leak, probably caused by an impact from a tiny space rock, drained the capsule of coolant. That left it at risk of reaching dangerously high temperatures during re-entry.
Russia thus sent up a replacement capsule last week, one which successfully docked with the station on Saturday. That helps resolve a potentially uncomfortable situation for Russia’s cosmonauts. Had anything gone wrong on the station, they would have been forced to rely on the damaged capsule for an emergency return to Earth. Now, however, they have a fully functional escape vessel once more.
The crew will stay longer in space than expected. Though they originally planned for a six month trip to the station, Russia was forced to rearrange plans to accommodate sending up the extra capsule. The cosmonauts will now stay for a full year on board, before they are replaced by another crew in September.