Space – Introduction
Outer space is the empty void that exists between various celestial bodies, including Earth. Space is not completely empty. It consists of a hard vacuum with a low density of particles, mostly plasma of hydrogen and helium, as well as some electromagnetic radiation, magnetic fields, neutrinos, dust and cosmic rays.
Density and temperature
The baseline temperature in spaces is 2.7 Kelvin (K). We know this based on the background radiation from the Big Bang. There is a fourth state of matter called plasma, which is neither solid, liquid nor gaseous. Plasma accounts for most of the baryonic or ordinary matter in space. It has a density of less than one hydrogen atom per cubic meter and a temperature of millions of Kelvin. It lies in the space between the galaxies. The local concentrations of plasma have condensed into stars and galaxies.
Dark matter
Observations have provided evidence that 90% of the mass in most galaxies is in an unknown form called “dark matter”. Dark matter interacts with other matter through gravitational forces, but not electromagnetic forces. Current data indicates that the majority of the mass-energy in the observable universe is a poorly understood vacuum energy of space. Astronomers, over time, have labeled this as “dark energy”. Intergalactic space occupies the maximum volume of the universe.
Even space has laws
The Outer Space Treaty established the framework for international space law. This treaty was passed by the United Nations General Assembly in 1967. The treaty prevents any claims of national sovereignty and allows all the states to freely explore outer space. The 1979 Moon Treaty made the surfaces of objects like planets and the orbital space around these bodies, the jurisdiction of the international community covered by the Space Law.
Despite the drafting of the UN resolutions for the peaceful use of outer space, anti-satellite weapons have been tested in Earth’s orbit. Current legislation only prohibits weapons of mass destruction, like nuclear weaponry and atomic bombs being placed into outer space.
Space exploration
Humans began the physical exploration of space during the 20th century. The advent of high-altitude balloon flights followed by manned rocket launchers facilitated this exploration. Yuri Gagarin of the Soviet Union first achieved Earth’s Orbit in 1961. Unmanned spacecraft have reached all the known planets in the solar system since then. The high cost of getting into space means that manned spaceflights have been limited to the lower Earth orbit and the moon. Voyager 1 became the first human-made spacecraft to enter interstellar space, leaving the solar system in August 2012.
An expensive affair
The current economic burden prevents us from becoming a spacefaring civilization. Certain proposed concepts for doing this involve non-rocket space launchers such as rockoon, skyhook, a rocket sled and an air launch.
Other concepts include momentum exchange tethers that make use of centrifugal acceleration and ionic propulsion.
Space elevators are also one of the proposed means of conducting space travel without the use of expensive resources. A space elevator extends into the space attached to the surface of Earth with the help of a ribbon-like structure.
These proposed concepts look promising when it comes to reducing the financial implications of space travel and exploration as they aim at saving on fuel, energy and loss of equipment and human lives.
Ccompiled by: Madhurani Chavan