Astronauts can't cry the same in space as they do on Earth. Your eyes make tears but they stick as a liquid ball. In fact, they sting a bit. So — space tears don't shed." Unless an astronaut wipes that water away, tears in space can form a giant clump that can break free of your eye, as The Atlantic explained.
The Outer Space Treaty
There is no claim for sovereignty in space; no nation can “own” space, the Moon or any other body. Weapons of mass destruction are forbidden in orbit and beyond, and the Moon, the planets, and other celestial bodies can only be used for peaceful purposes.
Sound does not travel at all in space. The vacuum of outer space has essentially zero air. Because sound is just vibrating air, space has no air to vibrate and therefore no sound.
Deep space missions will boost crew exposure to long-term microgravity, or weightlessness, and reduced gravity, according to the 100 Year Starship Project. Such low-gravity environments slow wound and fracture healing and accelerate bone loss, muscle loss and certain aspects of aging.
In space, blood can splatter even more than it usually does on Earth, unconstrained by gravity. Or it can pool into a kind of dome around a wound or incision, making it hard to see the actual trauma. (Fun fact: If you are bleeding more than 100 milliliters per minute, you are probably doomed.
This leaves only high-energy blue light to be reflected from our maroon veins. So, if you cut yourself in space, your blood would be a dark-red, maroon color.
The loudest sound in the universe definitely comes from black hole mergers. In this case the “sound” comes out in gravitational waves and not ordinary sound waves.
In space, no one can hear you scream. This is because there is no air in space – it is a vacuum. Sound waves cannot travel through a vacuum.
During the Mars-500 experiment, six astronaut crews stayed in an isolated space and lived as if they were on Mars for 520 days. Cosmic radiation and microgravity were not replicated in the experiment, so the slower aging process found by scientists is caused by social isolation and other relative effects.
Black holes are the darkest things in our universe because they emit no light whatsoever in any wavelength.
Almost every galaxy can be classified as a spiral, elliptical, or irregular galaxy. Only 1-in-10,000 galaxies fall into the rarest category of all: ring galaxies.
In space, there is no air, so sound has nothing to travel through. If someone were to scream in space, the sound wouldn't even leave their mouths.
Since tears on Earth only stream down a person's face because of gravity's influence, tears shed in microgravity do not fall. Instead, they pool on the face and could eventually drift off in little droplets that disperse throughout the orbiting science laboratory.
Without the proper diet and exercise routine, astronauts also lose muscle mass in microgravity faster than they would on Earth. Moreover, the fluids in the body shift upward to the head in microgravity, which may put pressure on the eyes and cause vision problems.
In space or on the Moon there is no atmosphere to scatter light. The light from the sun travels a straight line without scattering and all the colors stay together. Looking toward the sun we thus see a brilliant white light while looking away we would see only the darkness of empty space.
The Universe is thought to consist of three types of substance: normal matter, 'dark matter' and 'dark energy'. Normal matter consists of the atoms that make up stars, planets, human beings and every other visible object in the Universe.
But what of the average temperature of space away from the Earth? Believe it or not, astronomers actually know this value quite well: an extreme -270.42 degrees (2.73 degrees above absolute zero).
(Photo by NASA/CXC/Columbia Univ./C. Hailey et al.) For the first time in history, earthlings can hear what a black hole sounds like: a low-pitched groaning, as if a very creaky heavy door was being opened again and again.
NASA Has Captured 'Actual Sound' in Space and It's Honestly Terrifying. Vice. Start a conversation, not a fire.
Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color.
Also, dried blood often has a darker, rust-coloured quality: all dried blood has been oxygenated and then desiccated, causing the cells within it to die. This blood is often darker than either shade of red that can be seen in fresh blood.
Blood that has been oxygenated (mostly flowing through the arteries) is bright red and blood that has lost its oxygen (mostly flowing through the veins) is dark red. Anyone who has donated blood or had their blood drawn by a nurse can attest that deoxygenated blood is dark red and not blue.