Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

Movement in space is very difficult because if you push on something, you will move in the opposite direction. Astronauts on the Gemini missions complained that when they tried to use a spanner in space they spun in the opposite direction. Microgravity means that an astronaut is in danger of floating away mid-job, or losing a vital tool into outer space. To aid astronauts to move around outside, spacecraft are equipped with handles and special footholders into which feet can be locked.

When on a spacewalk, astronauts use safety tethers to stay close to their spacecraft. Tethers are like ropes. One end is hooked to the spacewalker. The other end is connected to the vehicle. The safety tethers keep astronauts from floating away into space. Astronauts also use tethers to keep tools from floating away. They tether their tools to their spacesuits.

Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER stands for simplified Aid for EVA Rescue. SAFER is worn like a backpack. It uses small jet thrusters to let an astronaut move around in space. If an astronaut were to become untethered and float away, SAFER would help him or her fly back to the spacecraft. Astronauts control SAFER with a small joystick, like on a video game.

When astronauts go on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits, astronauts have the oxygen they need to breathe. They have the water they need to drink. Astronauts put on their spacesuits several hours before a spacewalk. The suits are pressurized. This means that the suits are filled with oxygen.

Once in their suits, astronauts breathe pure oxygen for a few hours. Breathing only oxygen gets rid of all the nitrogen in an astronaut’s body. If they didn’t get rid of the nitrogen, the astronauts might get gas bubbles in their body when they walked in space. These gas bubbles can cause astronauts to feel pain in their shoulders, elbows, wrists and knees. This pain is called getting “the bends” because it affects the places where the body bends. Scuba divers can also get “the bends.”

Astronauts are now ready to get out of their spacecraft. They leave the spacecraft through a special door called an airlock. The airlock has two doors. When astronauts are inside the spacecraft, the airlock is airtight so no air can get out. When astronauts get ready to go on a spacewalk, they go through the first door and lock it tight behind them. They can then open the second door without any air getting out of the spacecraft. After a spacewalk, astronauts go back inside through the airlock.

Astronauts have to perform many different duties that involve leaving their spacecraft. The International Space Station, which is currently under construction, requires many adjustments that can only be done by trained personnel. Robotic equipment is used to put the components of the space station together, but much of the construction can only be done by hand. Astronauts also have to make repairs to complicated items such as the Hubble Space Telescope and damaged satellites.

Astronauts perform many tasks as they orbit Earth. The space station is designed to be a permanent orbiting research facility. Its major purpose is to perform world-class science and research that only a microgravity environment can provide. The station crew spends their day working on science experiments that require their input, as well as monitoring those that are controlled from the ground. They also take part in medical experiments to determine how well their bodies are adjusting to living in microgravity for long periods of time.

Working on the space station also means ensuring the maintenance and health of the orbiting platform. Crew members are constantly checking support systems and cleaning filters, updating computer equipment: doing many of the things homeowners must do to ensure their largest investment stays in good shape. Similarly, the Mission Control Center constantly monitors the space station and sends messages each day through voice or email with new instructions or plans to assist the crew members in their daily routines.

In the early days, the job description of an astronaut was basically that of being an observer – someone who would view and document what was happening. It didn’t take long for NASA to understand that human interaction would be required. These astronauts work with pilots to conduct experiments, launch satellites, and maintain spacecraft and equipment. Their background can be in engineering, science, or medicine. They can also work as astronaut educators, inspiring students to consider joining the US space program.

These astronauts serve as space shuttle and international space station pilots and commanders. They are responsible for the crew, the mission, the mission success and the safety of the flight. The Johnson Space Center provides a number of simulators and facilities to prepare the astronauts for their work in space, such as a neutral buoyancy simulator, which simulates weightlessness on earth, and a 200′ long and 40′ deep pool where astronauts train for spacewalks underwater.

When in orbit, most of the time is spent in the craft or space station. At times, a spacewalk is required to make repairs, or to deploy a satellite, and the astronaut must wear a space suit, or an EMU (extravehicular mobility unit) for protection. Most missions last two to three weeks, but long duration missions may run as long as half a year. Training for long duration missions is very arduous and takes approximately two to three years.

Every astronaut who leaves a spacecraft has to wear a specially designed spacesuit. It is called an Extra-Vehicular Activity (EVA) suit and acts like a miniature spaceship. Layers of material protect the astronaut from the Sun’s rays, as well as tiny particles of space dust that travel at hundreds of thousands of kilometres per hour. The suit provides everything that an astronaut needs to survive in space for short periods of time, including oxygen to breathe and water to drink. It also provides heating and cooling, communication devices and toilet facilities.

Astronauts must wear spacesuits whenever they leave a spacecraft and are exposed to the environment of space. In space, there is no air to breath and no air pressure. Space is extremely cold and filled with dangerous radiation. Without protection, an astronaut would quickly die in space. Spacesuits are specially designed to protect astronauts from the cold, radiation and low pressure in space. They also provide air to breathe. Wearing a spacesuit allows an astronaut to survive and work in space.

Spacesuits help astronauts in several ways. Spacewalking astronauts face a wide variety of temperatures. In Earth orbit, conditions can be as cold as minus 250 degrees Fahrenheit. In the sunlight, they can be as hot as 250 degrees. A spacesuit protects astronauts from those extreme temperatures.

Spacesuits supply astronauts with oxygen to breathe while they are in the vacuum of space. The suits contain water to drink during spacewalks. They protect astronauts from being injured from impacts of small bits of space dust. Space dust may not sound very dangerous, but when even a tiny object is moving many times faster than a bullet, it can cause injury. Spacesuits also protect astronauts from radiation in space. The suits even have visors to protect astronauts’ eyes from the bright sunlight.

A spacesuit is much more than a set of clothes astronauts wear on spacewalks. A fully equipped spacesuit is really a one-person spacecraft. The formal name for the spacesuit used on the space shuttle and International Space Station is the Extravehicular Mobility Unit, or EMU. “Extravehicular” means outside of the vehicle or spacecraft. “Mobility” means that the astronaut can move around in the suit. The spacesuit protects the astronaut from the dangers of being outside in space.

Nuclear reactions are the result of the strong nuclear force, which binds together the particles that form atoms. During a nuclear explosion, this powerful force is released, expelling vast amounts of energy.

A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device.

Atmospheric nuclear explosions are associated with mushroom clouds, although mushroom clouds can occur with large chemical explosions. It is possible to have an air-burst nuclear explosion without those clouds. Nuclear explosions produce radiation and radioactive debris.

The effects of a nuclear explosion on its immediate vicinity are typically much more destructive and multifaceted than those caused by conventional explosives. In most cases, the energy released from a nuclear weapon detonated within the lower atmosphere.

Depending on the design of the weapon and the location in which it is detonated, the energy distributed to any one of these categories may be significantly higher or lower. The blast effect is created by the coupling of immense amounts of energy, spanning the electromagnetic spectrum, with the surroundings. The environment of the explosion (e.g. submarine, ground burst, air burst or exo-atmospheric) determines how much energy is distributed to the blast and how much to radiation. In general, surrounding a bomb with denser media, such as water, absorbs more energy and creates more powerful shockwaves while at the same time limiting the area of its effect. When a nuclear weapon is surrounded only by air, lethal blast and thermal effects proportionally scale much more rapidly than lethal radiation effects as explosive yield increases. The physical-damage mechanisms of a nuclear weapon (blast and thermal radiation) are identical to those of conventional explosives, but the energy produced by a nuclear explosion is usually millions of times more powerful per unit mass and temperatures may briefly reach the tens of millions of degrees.

Energy from a nuclear explosion is initially released in several forms of penetrating radiation. When there is a surrounding material such as air, rock, or water, this radiation interacts with and rapidly heats the material to an equilibrium temperature (i.e. so that the matter is at the same temperature as the fuel powering the explosion). This causes vaporization of the surrounding material, resulting in its rapid expansion. Kinetic energy created by this expansion contributes to the formation of a shockwaves. When a nuclear detonation occurs in air near sea level, much of the released energy interacts with the atmosphere and creates a shockwave which expands spherically from the center. Intense thermal radiation at the hypocenter forms a nuclear fireball which, if the burst is low enough, is often associated with a mushroom cloud. In a high-altitude burst, where the density of the atmosphere is low, more energy is released as ionizing gamma radiation and X-rays than as an atmosphere-displacing shockwave.

From Earth, space can seem calm and quiet, but in actual fact it is deadly. If humans ventured into space without the protection of a spacesuit they would die almost instantly. The lack of oxygen would mean suffocation. But before this, the lack of pressure would cause gases in the blood to separate as if it were boiling. With no protection from the Sun’s harmful ultraviolet radiation, the astronaut would be burned to death.

What happens to your body in space? NASA’s Human Research Program has been unfolding answers for over a decade. Space is a dangerous, unfriendly place. Isolated from family and friends, exposed to radiation that could increase your lifetime risk for cancer, a diet high in freeze-dried food, required daily exercise to keep your muscles and bones from deteriorating, a carefully scripted high-tempo work schedule, and confinement with three co-workers picked to travel with you by your boss.

But what, exactly, happens to your body in space, and what are the risks? Are risks the same for six months on the space station versus three years on a Mars mission? No. There are several risks NASA is researching for a Mars mission. The risks are grouped into five categories related to the stresses they place on the space traveler: Gravity fields, isolation/confinement, hostile/closed environments, space radiation, and distance from Earth.

Scott Kelly was the first American to spend nearly one year in space aboard the International space Station, twice the normal time. Science takes time, and researchers are eagerly analyzing results of the mission to see how much more the body changes after a year in space. One year is a stepping stone to a three-year journey to Mars, and Scott’s data will help researchers determine whether the solutions they’ve been developing will be suitable for such long, onerous journeys.

Together, the four forces can explain everything that happens in the Universe. Many scientists are now working to prove that they are all separate parts of the same universal force that once existed at the birth of the Universe.

A theory of everything (TOE or ToE), final theory, ultimate theory, or master theory is a hypothetical single, all-encompassing, coherent theoretical framework of physics that fully explains and links together all physical aspects of the universe. Finding a TOE is one of the major unsolved problems in physics. Over the past few centuries, two theoretical frameworks have been developed that, together, most closely resemble a TOE. These two theories upon which all modern physics rests are general relativity (GR) and quantum field theory (QFT). GR is a theoretical framework that only focuses on gravity for understanding the universe in regions of both large scale and high mass: stars, galaxies, clusters of galaxies, etc. On the other hand, QFT is a theoretical framework that only focuses on three non-gravitational forces for understanding the universe in regions of both small scale and low mass: sub-atomic particles, atoms, molecules, etc. QFT successfully implemented the Standard Model that describes the three non-gravitational forces – strong nuclear, weak nuclear, and electromagnetic force — as well as all observed elementary particles.

Physicists have experimentally confirmed virtually every prediction made by GR and QFT when in their appropriate domains of applicability. Nevertheless, GR and QFT are mutually incompatible – they cannot both be right. Since the usual domains of applicability of GR and QFT are so different, most situations require that only one of the two theories be used. As it turns out, this incompatibility between GR and QFT is only an issue in regions of extremely small scale – the Planck scale – such as those that exist within a black hole or during the beginning stages of the universe (i.e., the moment immediately following the Big Bang). To resolve the incompatibility, a theoretical framework revealing a deeper underlying reality, unifying gravity with the other three interactions, must be discovered to harmoniously integrate the realms of GR and QFT into a seamless whole: the TOE is a single theory that, in principle, is capable of describing all phenomena in the universe.

In pursuit of this goal, quantum gravity has become one area of active research. One example is string theory, which evolved into a candidate for the TOE, but not without drawbacks (most notably, its lack of currently testable predictions) and controversy. String theory posits that at the beginning of the universe (up to 10?43 seconds after the Big Bang), the four fundamental forces were once a single fundamental force. According to string theory, every particle in the universe, at its most microscopic level (Planck length), consists of varying combinations of vibrating strings (or strands) with preferred patterns of vibration. String theory further claims that it is through these specific oscillatory patterns of strings that a particle of unique mass and force charge is created (that is to say, the electron is a type of string that vibrates one way, while the up quark is a type of string vibrating another way, and so forth).