Space (Physics) Part-I

Cassini was a spacecraft developed by NASA to study ringed planet (Saturn) and its domain. TechSar is an Israeli reconnaissance satellite launched by India's launching vehicle PSLV. Apophis is an asteroid and Spitzer was a space infrared telescope developed by NASA.

The experiment in question refers to evolved Laser Interferometer Space Antenna (eLISA) which is a proposed space probe to detect and accurately measure gravitational waves. It is a space-based gravitational wave observatory building on the success of LISA Pathfinder and LIGO.

The European Space Agency (ESA) is leading this mission with supports from NASA and an international consortium of scientists. eLISA is a spectacular plan of setting into space three spacecrafts, a mother and two daughter spacecraft, which will fly in a triangular formation, trailing the Earth in its orbit around the sun at a distance of over 50 million km.

Each arm of the imaginary equilateral triangle will measure about a million km. The distance between the spacecrafts is precisely monitored by laser interferometers to detect a passing gravitational wave. This mission is slated for 2034.

The experiment in question refers to evolved Laser Interferometer Space Antenna (eLISA) which is a proposed space probe to detect and accurately measure gravitational waves. It is a space-based gravitational wave observatory building on the success of LISA Pathfinder and LIGO.

The European Space Agency (ESA) is leading this mission with supports from NASA and an international consortium of scientists. eLISA is a spectacular plan of setting into space three spacecrafts, a mother and two daughter spacecraft, which will fly in a triangular formation, trailing the Earth in its orbit around the sun at a distance of over 50 million km.

Each arm of the imaginary equilateral triangle will measure about a million km. The distance between the spacecrafts is precisely monitored by laser interferometers to detect a passing gravitational wave. This mission is slated for 2034.

In 2009, British scientists announced that they have designed a special spacecraft that can save the Earth from a catastrophic collision. The 10 ton spacecraft named 'Gravity Tractor' would be deployed to intercept an asteroid en route to the earth and has the ability to fly 160 ft alongside it.

The idea of a gravity tractor was put forward in 2005 by Edward T. Lu and Stanley G. Love.

Recently, scientists observed that billions of light years away, two black holes have collided to create a larger one-the biggest black hole merger yet detected. It has a mass more than 80 times that of the sun. The significance of this observation is that the gravitational waves were detected.

The resulting energy injected into the fabric of spacetime was also record breaking, with five sun's worth of mass released in the form of gravitational waves as the two holes spiralled in towards each other.

Such titanic amounts of energy meant that the signal was still detectable by the time it reached gravitational wave detectors on Earth.

The first direct observation of gravitational waves was made on 14 September, 2015 and was announced by the LIGO (Laser Interferometer Gravitational Wave Observatory) on 11 February, 2016.

Detection of microwaves in space and observation of redshift phenomenon in space are cited by the scientists as evidence for the continued expansion of the universe. In 1998 two research team presented their findings, first headed by Saul Perlmutter and Adam Riess and another by Brian Schmidt.

Both of these teams explored that the universe which just came after the event of big-bang that is expanding continuously. These two research teams found that over 50 distant supernova whose light became more weaker than expected, is the sign that the expansion of the universe is accelerating.

For their vast contribution in Physics, the Royal Swedish Academy of Science had decided to award them with the Nobel Prize in Physics for 2011.

The concept of expanding universe is based on Doppler effect. It was named after Christian Doppler, who first came up with the idea in 1942. Edwin Hubble used the Doppler Effect to determine that universe is expanding.

Hubble found that the light from distant galaxies was shifted towards lower frequencies, to the red end of the spectrum. This is known as a red Doppler shift or a red-shift.

When light travels near a huge celestial body or black hole it bends towards the celestial body. As per the prediction of Albert Einstein, the astronomers have found that the universe is expanding continuously and a heavenly body with huge mass tends to bend (warp) the space-time.

This is known as warping of the space-time. This is why light seems to bend when it passes near a star or black hole.

The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of observation and understanding of the Universe. In astrophysics, an event horizon is a boundary beyond which events cannot affect an observer.

In an expanding universe, the speed of expansion reaches and even exceeds - the speed of light, preventing signals from traveling to some regions. With reference to black holes, 'event horizon' is the boundary defining the region of space around a black hole from which nothing (not even light) can escape.

Singularities are regions of space where the density of matter, or the curvature of spacetime, becomes infinite. In such locales, the standard concepts of space and time cease to have any meaning.

Singularities are predicted to occur in all black holes and also in certain models of the Universe. String theory is a concept in theoretical physics that states the universe is constructed by tiny vibrating strings, smaller than the smallest subatomic particles.

According to this theory, as the strings vibrate, twist and fold, they produce effects in many, tiny dimensions that humans interpret as everything from particle physics to large-scale phenomena like gravity.

The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetic force, weak nuclear force, and the strong nuclear force excluding gravity) in the universe and classifying all known elementary particles.