Space is nothing but the empty area (shunya) above the atmosphere approximately 100 miles from the surface. however we already know that there is no starting and ending point of the space it is expanded to infinity in all directions, there are different categories of space that is interplanetary space which is the space between planets, interstellar space which is the space between the stars in our galaxy and intergalactic space which is the space between the galaxies in-universe.
Observation of objects in space is called astronomy. Astronauts go to the International space station and observe what they want they will research the things and they will do the spacewalk. The international space station is about 400km above the surface. Astronauts will be in the International space station by docking space shuttle with the international space station.
Is gravity is zero in space?
Gravity makes the moon and human-made satellites revolving around the earth in an orbit. Gravity in space is not zero. Gravity decreases with distance.
Does less gravity makes weightless feeling of astronaut
People have an illusion that astronauts are floating in space but the fact is that they are falling but because of large tangential velocity and force of gravity brings them in an orbit. Weightless feeling of an astronaut is not because of less force of gravity, it is because of their tangential velocity (the tangential velocity is the velocity measured at any point tangent to the rotating wheel in this case rotating earth), the force of gravity makes them or allow them to remain in an orbital motion. The earth and satellites in orbits revolve or moves with the same velocity so satellite looking like it is stationary.
If the astronaut wants to walk in space he must wear the white coloured spacesuit for visible of an astronaut to other astronauts (orange-coloured spacesuit while for the landing in the sea for visible of astronauts to helpers). A lot of debris also there in space, somehow spacesuit will protect him from the collision of debris with him, and he must be attached with a steel probe with International space station. what if the probe is detached Safer (Simplified aid for EVA rescue) is there on their back, it is just simply a jet pack system.
What do they eat?
Definitely, they can not eat as they eat on earth, most of the food is served by mixing with water. Some foods like brownies and fruits can be taken by them directly means natural forms. Most of the foods like macaroni are mixed with water to avoid floating in the same way condiments like pepper, salt is not provided in the powdered form provided in liquid form because powdered food can clog the air vents.
Does exercise must?
we unknowingly move the bones by means of turning head moving hands-on earth in our daily life but in space, this scenario will not be there so they must do exercise on an average two hours a day to prevent the bones and muscle loss otherwise bone and muscles become weak.
What do they feel about their weight?
Weight is directly proportional to gravity. Because of the microgravity astronauts feel weightless. For an example lifting of 200kg weight is hard on earth but in space, it is easy to lift. This is the reason why astronauts can not walk on earth sometime after landing on earth from space they feel very heavy.
Why space looks black?
We are all having a question that why space looks black even though there are sun, stars and moon so on. *This is purely according to my knowledge- when we are on earth sky looks blue in day time ( when sun rays hit water molecules sky is blue) and looks black in night time at night time there is no sun the light travelled from space does not hit our eyes because we are in earth atmosphere we are not in space so our eyes can not reflect the light so space is black.
Almost all nations are exploring the space for scientific research, national prestige, ensuring the future survival of humans and military development.
NASA receives the applications from who had worked 1000 hours in flight. Next NASA will do the medical test, physical test and by conducting interviews NASA will select the persons who are eligible for astronaut training later they will give astronaut training and they will send them to space to explore the space.
KNow more about satellite HERE.