You may have heard the theory surrounding the glass of water seen in a video taken onboard China's Tiangong space station, that has led some to claim it's proof the footage was faked.
The video in question shows a glass of clear liquid sitting unperturbed on a table aboard the Chinese space station, causing some viewers to question why the water isn't floating out of the glass, given it's in a weightless environment.
More debunking science
Indeed, why is the glass itself not floating away?
We've seen videos of astronauts onboard the International Space Station showing what water looks like in a weightless environment, and it's a pretty amazing display of physics.
So what's going on here?
Luckily, the Associated Press debunked this conspiracy theory back in 2023.
How the theory arose
The glass of water was seen on the Chinese Tiangong space station during a live-streamed science lesson by the Shenzhou‑13 crew in late 2021.
This prompted some discussion online as to whether this was a case of catastrophic oversight by a Chinese space agency looking to trick the rest of the world into believing it had a sophisticated space program.
However, the Associated Press looked into the physics behind what we're seeing, as part of their ongoing effort to "address widely shared misinformation".
Debunking the theory
The Associated Press spoke to Jordan Bimm, a postdoctoral researcher and space historian at the University of Chicago.
He explained that liquid in a glass in weightless environment tends to cling rather than drift:
"Water molecules like to stick to glass and also to other water molecules more than they like to disperse in the air," Bimm told AP.
"So if there is no external force, water remains in ‘clumps’ in the weightless environment, and in this case inside the glass."
Bimm also said surface tension "works to help maintain the static shape and presents the illusion of how water would act on the ground."
Behind the scenes
China’s crewed space program responded to the accusations online by posting a behind‑the‑scenes video on social media network Weibo showing astronaut Wang Yaping pouring water into the glass through a straw, then securing it with adhesive strips to the work surface.
And in a follow‑up experiment, the crew submerged a ping‑pong ball in the water.
On Earth, the ping-pong ball would have floated to the surface, but in the weightless environment of the space station, the ball stays suspended underwater.
Further proof that the physics match what you would expect to happen in space, rather than on Earth.
Molly Silk, a doctoral researcher at the University of Manchester in the UK who has studied the Chinese space program, also spoke to the Associated Press about the video.
"It is extremely unlikely that the video was faked, as Chinese space program actors have very little reason to fake a video," she told AP.
"The presence of the space station has been verified by international actors, including China’s biggest space competitor the US."
Indeed, we know for a fact that China has a sophisticated space program, which is hardly surprising given the size and population of the country, as well as its renowned technological prowess.
Recent successes by the Chinese space agency include the Chang'e 6 mission to return samples from the far side of the Moon.
And in May 2025, Moon samples collected by the Chang'e 5 mission were given to the UK's Open University for study by scientists.
Bottom line
The allegation that the still water in a glass proves China faked the video of their astronauts on board a space station has been disproven.
Both knowledge of physics and direct evidence from NASA and independent researchers show the scenario is consistent with microgravity conditions aboard Tiangong.
