Space, in brief

Scientists working with LHAASO, an observatory that catches the showers of particles set off when something from space hits the air, published a result on 24 September. [1]

It appeared in the journal Nature Astronomy, about a year after the team first sent it in. [1]

They picked up very high-energy gamma rays, the most energetic kind of light, coming from five giant clouds of gas close to us in the Milky Way. [1]

The team combined the signal from all five clouds, using 4.5 years of the observatory's records. [1]

Cosmic rays are fast particles flying through the galaxy. When they crash into the gas in a cloud, the crash gives off gamma rays. [1]

The amount of gamma light matched what cosmic rays hitting the gas should make, across energies from 1 to 100 TeV, a unit for the energy of one particle. [1]

That makes each cloud a measuring station. Its glow shows how many cosmic rays are passing through that part of the galaxy, and how their energies are spread. [1]

The team also looked for the knee, a bend in the count of cosmic rays where the most energetic ones start to get rarer faster. [1]

They found no clear knee. Their data fit a knee at about 0.9 PeV or higher, which is 900 TeV, but a lower one cannot be ruled out yet. [1]

The result agrees with recent measurements of cosmic rays made by instruments on the ground. [1]

The authors say the clouds can now be used to map where cosmic rays are across the Milky Way, and so help work out where the particles come from. [1]

Why it matters. The next step the authors name is using more clouds to map cosmic rays across the Milky Way, and the open test is whether more data pin the knee at 0.9 PeV or show it lower. [1]

SpaceX said on 24 September that it had finished a wet dress rehearsal for Flight 14 of Starship, its giant reusable rocket. [2] In that test the team fills the rocket with fuel and goes through launch day without lighting the engines. [2] The booster and ship were stacked on the pad at Starbase in Texas overnight on 23 September. [3] The launch window opens at 8:15 a.m. US Eastern time on 28 September, pending approval from the US Federal Aviation Administration. [3] Earlier flights lasted about an hour, and this one is planned to last about ten. [3]

Why it matters. All 13 earlier Starship flights stopped short of orbit on purpose, and this is the first try to reach it. [3] If it works, the ship will release 26 of SpaceX's new, larger Starlink internet satellites and circle Earth six times before splashing down in the Pacific off Chile. [2][4]

A Falcon 9 rocket launched 27 more Starlink internet satellites from Vandenberg in California on the evening of 19 September. [5] Its first stage landed on a ship in the Pacific about eight and a half minutes later, on that booster's 17th flight. [5] Starlink now has more than 11,100 working satellites, according to the satellite tracker Jonathan McDowell. [5] At this year's rate, SpaceX would fly Falcon 9 149 times in 2026, down from 165 in 2025. [5]

Why it matters. The bigger V3 satellites that Starship is carrying are meant to replace this whole network in time. [3] None of them can be put into service until Starship reaches orbit. [3]

Russia's Progress M-25 cargo ship, which NASA calls Progress 96, docked with the International Space Station at 9:44 a.m. US Eastern time on 19 September. [6] It flew in on its own automatic system, while two cosmonauts stood by with remote controls they did not need. [6] Its launch from Baikonur in Kazakhstan was held back a week by a problem in the third stage of its Soyuz-2-1b rocket. [6] It was the first time that version of the rocket carried a Progress. [6]

Why it matters. It brought 2.8 tons of food, fuel and supplies for the seven people on the station and will stay about five months. [6][7] Then it will be filled with rubbish and burned up in the air, like every station freighter except SpaceX's Dragon. [7]