Space, in brief

A cloud of magnetised gas left the Sun at 00:48 GMT on 15 December 2024, and seventeen spacecraft caught some part of it. [1]

That is a record. The previous best was ten, and those ten sat almost in a line from the Sun out past Earth. [1]

A line of instruments measures timing and speed well. It cannot measure shape, because every one of them looks from the same direction. [1]

Spread wide, the fleet showed two lobes rather than one: a fast lobe aimed at Earth and Mars, and a bigger, slower one off to the side. [1]

SOHO, the telescope that stares at the Sun from near Earth, has watched without a break for over thirty years. It saw only the slower lobe. [1]

The lobe that reached Earth averaged 840 kilometres a second. The other averaged 534, and had slowed to about 400 by the time it passed STEREO-A, a probe that runs ahead of Earth. [1]

Europe's Solar Orbiter sat almost on the Sun-Earth line and detected nothing at all. That silence helped fix the cloud's shape, by ruling out where it was not. [1][2]

The cloud was met near Mercury on 16 December, at Earth on the 17th, at STEREO-A on the 18th and at Mars on the 19th and 20th. [1]

None of the seventeen was built for this. Europa Clipper read it while flying past Mars to borrow speed from the planet, on its way to Jupiter. [1]

A missed cloud costs warning time, and fast ones drive shocks that fling out particles dangerous to anyone outside Earth's magnetic shield, the study's lead author said. [1]

Nobody knows whether lopsided eruptions are common and usually missed, or genuinely rare. Telling those apart needs more instruments away from the Sun-Earth line. [1]

This particular cloud was not strong enough to produce much aurora, the shifting lights seen near the poles. Almost nobody on the ground noticed it. [1]

Why it matters. Watch whether the next big eruption gets a reading from a probe well off the Sun-Earth line; that is what would show whether lopsided clouds are ordinary.

NASA's Nancy Grace Roman Space Telescope is due to lift off from Kennedy Space Center no earlier than 30 August, on a Falcon Heavy. [3][4][6] One image runs to 300 megapixels. [3]

Why it matters. Its data becomes public as soon as it is processed, so any team can work on it at once. [4][5]

The European Space Agency has put the Ariane 6 Block 3 upgrade on ice, including a lighter carbon upper stage. [7] Governments already subsidise each flight by 32 to 38 million euros. [7]

Why it matters. A planned probe to Saturn's moon Enceladus was counting on it, while Canada spends 2.3 billion dollars over fifteen years building its own. [7][19]

The Pentagon extended SpaceX's Starshield service across military aircraft without a contest, saying no rival terminal had passed the required aviation tests. [8] LeoLabs won 20.68 million dollars for a movable radar, and SpaceWERX picked 11 firms for deals worth 562.5 million dollars. [9][23]

Why it matters. The government had already spent 51.9 million dollars qualifying SpaceX's terminals, and that spending became the argument against testing anyone else's. [8]

A former astronomer reading a paper on his phone spotted a faint ribbon of stars beside a dwarf galaxy 115 million light-years away. [10]

Why it matters. Ribbons like it are pulled apart by dark matter, and this is the first one found beyond the Milky Way. [10]

Japan's MMX spacecraft is set to launch on 19 October, to collect a sample from Phobos, the larger Martian moon, and bring it home. [11]

Why it matters. The same two moons drew two more looks this week: Deimos's dent traced to a single impact, and Perseverance filming Phobos cross the Sun. [12][13][14]

NASA added a 34-metre antenna to its Deep Space Network, the three-site radio system that talks to more than 40 spacecraft. [15]

Why it matters. France's Miratlas is raising 20 million euros to map where skies are clear enough for laser links to orbit. [18]

NASA's Anil Menon and ESA's Sophie Adenot spent six and a half hours outside the space station installing a high-speed antenna. [16]

Why it matters. It was the third spacewalk this month, with another due in September. [16]

Lonestar Data Holdings hired the Polish firm Ares Shield to defend its orbital data centres, in a deal worth up to 6 million dollars. [17]

Why it matters. The chosen weapon is a microwave pulse, because shooting at a satellite would leave debris behind. [17]

Astronomers found 14 galaxies whose vast jets of gas have gone quiet, a first clear look at the engine switching off. [21] A simulation tied central star clusters to the black holes they surround. [22]

Why it matters. A separate paper argues dark stars seeded the first giant black holes, which would explain a faint background hum of ripples in space itself. [20]