Why don't we see the sun in space?
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.
It is a common misconception that the Sun is yellow, or orange or even red. However, the Sun is essentially all colors mixed together, which appear to our eyes as white. This is easy to see in pictures taken from space.
Can astronauts see stars while in outer space? In short, Yes they can! There have been many reports from astronauts stationed on the ISS like Mr Jack Fischer (@Astro2fish) who shared the below video a few years ago.
A succession of astronauts have described the smell as '… a rather pleasant metallic sensation ... [like] ... sweet-smelling welding fumes', 'burning metal', 'a distinct odour of ozone, an acrid smell', 'walnuts and brake pads', 'gunpowder' and even 'burnt almond cookie'.
Space is very, very cold. The baseline temperature of outer space is 2.7 kelvins (opens in new tab) — minus 454.81 degrees Fahrenheit, or minus 270.45 degrees Celsius — meaning it is barely above absolute zero, the point at which molecular motion stops.
How dark does space get? If you get away from city lights and look up, the sky between the stars appears very dark indeed. Above the Earth's atmosphere, outer space dims even further, fading to an inky pitch-black. And yet even there, space isn't absolutely black.
Space is a vacuum.
With no molecules in the vacuum of space there is no medium for the sound waves to travel through. So there is no sound.
The shuttle/ISS Extravehicular Mobility Unit (EMU) aka spacesuit incorporates a gold-film plated sun visor to protect the astronaut's vision when looking in the general direction of the sun. It is called the Extravehicular Visor Assembly.
The real colour of the Sun is actually white and the reason the dwarf star generally looks yellow is because of a strange play of physics of light which makes the sun appear yellow most of the time. For those who think that the Sun is actually yellow, that is not its true colour.
The surprising answer is it does both: first it boils and then it freezes! We know this because this is what used to happen when astronauts felt the call of nature while in space.
Can astronauts hear in space?
When astronauts are out in space, they can whistle, talk, or even yell inside their own spacesuit, but the other astronauts would not hear the noise. In fact, the middle of space is very quiet. Sound travels in waves, and it moves at different speeds through air or water or other materials.
For every watt our sun puts out, it produces 93 lumens of visible light. So at earth's orbit, for each square meter, our sun puts out 127,000 lumens. That is very bright.
Scientists have recently observed for the first time that, on an epigenetic level, astronauts age more slowly during long-term simulated space travel than they would have if their feet had been planted on Planet Earth.
In either case, you could never get to the end of the universe or space. Scientists now consider it unlikely the universe has an end – a region where the galaxies stop or where there would be a barrier of some kind marking the end of space. But nobody knows for sure.
It's also very cold in space. You'll eventually freeze solid. Depending on where you are in space, this will take 12-26 hours, but if you're close to a star, you'll be burnt to a crisp instead.
There's a limit to how much of the universe we can see. The observable universe is finite in that it hasn't existed forever. It extends 46 billion light years in every direction from us. (While our universe is 13.8 billion years old, the observable universe reaches further since the universe is expanding).
A total of 32 monkeys have flown in space, including (from left): rhesus macaques, cynomolgus monkeys, squirrel monkeys and pig-tailed monkeys. Chimpanzees have also flown. In the 1950s, the Soviet Union launched a total of 12 dogs on various suborbital flights.
"No human can survive this — death is likely in less than two minutes," Lehnhardt said. According to NASA's bioastronautics data book (opens in new tab), the vacuum of space would also pull air out of your lungs, causing you to suffocate within minutes.
First, the good news: Your blood won't boil. On Earth, liquids boil at a lower temperature when there's less atmospheric pressure; outer space is a vacuum, with no pressure at all; hence the blood boiling idea.
(If the universe weren't expanding, then the one or two atoms per cubic centimeter encountered by the bullet in the near-vacuum of space would bring it to a standstill after 10 million light-years.)
What was there before the universe?
In the beginning, there was an infinitely dense, tiny ball of matter. Then, it all went bang, giving rise to the atoms, molecules, stars and galaxies we see today. Or at least, that's what we've been told by physicists for the past several decades.
Space Environment
So, in order for sound to travel, there has to be something with molecules for it to travel through. On Earth, sound travels to your ears by vibrating air molecules. In deep space, the large empty areas between stars and planets, there are no molecules to vibrate. There is no sound there.
No, there isn't sound in space.
This is because sound travels through the vibration of particles, and space is a vacuum. On Earth, sound mainly travels to your ears by way of vibrating air molecules, but in near-empty regions of space there are no (or very, very few) particles to vibrate – so no sound.
In a new study, Stanford physicists Andrei Linde and Vitaly Vanchurin have calculated the number of all possible universes, coming up with an answer of 10^10^16.
Fires can't start in space itself because there is no oxygen – or indeed anything else – in a vacuum.
Jim Fuller. 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.
We can't smell space directly, because our noses don't work in a vacuum. But astronauts aboard the ISS have reported that they notice a metallic aroma – like the smell of welding fumes – on the surface of their spacesuits once the airlock has re-pressurised.
NASA's Parker Solar Probe is the first-ever mission to "touch" the Sun. The spacecraft, about the size of a small car, travels directly through the Sun's atmosphere --ultimately to a distance of bout 4 million miles from the surface.
Parker Probe, take a bow | Video. NASA spacecraft called the Parker Probe created history by touching the Sun.
What color is the hottest in space?
Summary. Stars exist in a range of colors: red, orange, yellow, green, white and blue with red being the coolest and blue being the hottest.
Every direction you looked in space you would be looking at a star. Yet we know from experience that space is black!
Instead, you would face another gruesome fate first: your blood, your bile, your eyeballs –will boil furiously, since the low pressure of the vacuum massively reduces the boiling point of water. It is only then that you would freeze.
Without gravity, hot air expands but doesn't move upward. The flame persists because of the diffusion of oxygen, with random oxygen molecules drifting into the fire. Absent the upward flow of hot air, fires in microgravity are dome-shaped or spherical—and sluggish, thanks to meager oxygen flow.
If you take it in space nothing happens cause there is no pressure on the outside of the bottle.
If atoms come to a complete stop, they are at absolute zero. Space is just above that, at an average temperature of 2.7 Kelvin (about minus 455 degrees Fahrenheit).
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.
Both the Earth and the International Space Station (ISS) receive their heat (energy) from the Sun. However, the way heat is transferred is completely different. Heat conduction and convection do not occur in space since there is no air in space. Heat transfers in space, which is a vacuum, only by radiation.
It turns out that our Sun is an average sized star. There are bigger stars, and there are smaller stars. We have found stars that are 100 times bigger in diameter than our sun. Truly, those stars are enormous.
How long will our sun last?
So our Sun is about halfway through its life. But don't worry. It still has about 5,000,000,000—five billion—years to go. When those five billion years are up, the Sun will become a red giant.
Conduction and convection can't happen in empty space due to the lack of matter and heat transfer occurs slowly by radiative processes alone. This means that heat doesn't transfer quickly in space.
However, as astronaut Chris Hadfield notes, in microgravity, "your eyes make tears but they stick as a liquid ball." In other words, astronauts technically can't cry. Sure, you can get a watery substance to come out of your eyes, but it doesn't fall like it ordinarily does on Earth.
Red-green and yellow-blue are the so-called "forbidden colors." Composed of pairs of hues whose light frequencies automatically cancel each other out in the human eye, they're supposed to be impossible to see simultaneously.
The past no longer exists, so no one can directly look at it. Instead, the telescopes are looking at the present-time pattern of a beam of light. Since the beam of light has been traveling through the mostly-empty vacuum of space for millions of years, it has been largely undisturbed.
The shuttle/ISS Extravehicular Mobility Unit (EMU) aka spacesuit incorporates a gold-film plated sun visor to protect the astronaut's vision when looking in the general direction of the sun. It is called the Extravehicular Visor Assembly.
Not only could you damage your eye, but you can also damage the lenses in the telescope. There is a particular color of red (called H-alpha, coming from hydrogen atoms) that is good for viewing the Sun's chromosphere, the part of the Sun directly above the surface, and that shows the best solar activity.
The Sun is a huge ball of hydrogen and helium held together by its own gravity. The Sun has several regions. The interior regions include the core, the radiative zone, and the convection zone.
The color of the sun is white. The sun emits all colors of the rainbow more or less evenly and in physics, we call this combination "white". That is why we can see so many different colors in the natural world under the illumination of sunlight.
