cross-posted from: https://lemmy.ml/post/18256668

A solar superstorm in May caused thousands of satellites to simultaneously maneuver to maintain altitude due to the thickening of the upper atmosphere, creating potential collision hazards as existing prediction systems struggled to cope. Space.com reports:

According to a pre-print paper published on the online repository arXiv on June 12, satellites and space debris objects in low Earth orbit -- the region of space up to an altitude of 1,200 miles (2,000 kilometers) -- were sinking toward the planet at the speed of 590 feet (180 meters) per day during the four-day storm. To make up for the loss of altitude, thousands of spacecraft began firing their thrusters at the same time to climb back up. That mass movement, the authors of the paper point out, could have led to dangerous situations because collision avoidance systems didn't have time to calculate the satellites' changing paths.

The solar storm that battered Earth from May 7 to 10 reached the intensity of G5, the highest level on the five-step scale used by the National Oceanic and Atmospheric Administration (NOAA) to assess the strength of solar storms. It was the strongest solar storm to hit Earth since 2003. The authors of the paper, however, pointed out that the environment around the planet has changed profoundly since that time. While only a few hundred satellites were orbiting Earth twenty years ago, there are thousands today. The authors of the paper put the number of "active payloads at [low Earth orbit]" at 10,000. [...] The new paper points out that space weather forecasts ahead of the May storm failed to accurately predict the duration and intensity of the event, making satellite collision predictions nearly impossible.

On the upside, the storm helped to clear out some junk as defunct satellites and debris fragments spiraled deeper into the atmosphere. The authors of the report estimate that thousands of space debris objects lost several kilometers in altitude during the storm. More powerful solar storms can be expected in the coming months as the peak of the current solar cycle -- the 11-year ebb and flow in the number of sunspots, solar flares and eruptions -- is expected in late 2024 and early 2025.

The paper can be found here.

Their ongoing interaction was set in motion between 25 and 75 million years ago, when the Penguin (individually catalogued as NGC 2936) and the Egg (NGC 2937) completed their first pass. They will go on to shimmy and sway, completing several additional loops before merging into a single galaxy hundreds of millions of years from now.

The James Webb Space Telescope takes constant observations, including images and highly detailed data known as spectra. Its operations have led to a ‘parade’ of discoveries by astronomers around the world. It has never felt more possible to explore every facet of the Universe.

The telescope’s specialisation in capturing infrared light – which is beyond what our own eyes can detect – shows these galaxies, collectively known as Arp 142, locked in a slow cosmic dance. Webb’s observations (which combine near- and mid-infrared light from Webb’s NIRCam [Near-InfraRed Camera] and MIRI [Mid-Infrared Instrument], respectively) clearly show that they are joined by a blue haze that is a mix of stars and gas, a result of their mingling.

. . .

And here's a followup video on the James Webb Space Telescope YouTube channel: A Tour of Arp 142

A SpaceX Falcon 9 rocket suffered an upper stage engine failure and deployed a batch of Starlink internet satellites into a perilously low orbit after launch from California Thursday night, the first blemish on the workhorse launcher's record in more than 300 missions since 2016.

Will it be able to compete at all costs wise, given its lack of reusability?

BBC mentioned it would probably be a decade before the ESA reaches that sort of technology.

Sorry for dumb question I haven’t been following space stuff at all. But I read a couple articles on yesterdays launch and was interested.

Launch window opens at: 2024-07-09 19:00 UTC

Launch thread has been posted over at [email protected]:

Ariane 6 Demo Flight Launch Thread! (ESA Rideshares)

edit: title was modified to call attention to the discussion in the comments

The article is by Rajendra Gupta, Adjunct professor Physics @ L’Université d’Ottawa/University of Ottawa

First few lines:

Do constants of nature — the numbers that determine how things behave, like the speed of light — change over time as the universe expands? Does light get a little tired travelling vast cosmic distances? It was believed that dark matter and dark energy explained these cosmological phenomena, but recent research indicates that our universe has been expanding without dark matter or dark energy.

Doing away with dark matter and dark energy resolves the “impossible early galaxy problem,” that arises when trying to account for galaxies that do not adhere to expectations regarding to size and age. Finding an alternative to dark matter and energy that complies with existing cosmological observations, including galaxy distribution, is possible.

“We need to consider alternatives to dark matter that better explain cosmological observations” (see comments for discussion)

cross-posted from: https://lemmy.ml/post/17634058