Rajasthan Board RBSE Class 10 Science Notes Chapter 17 Search of Life Outside Earth
Position of Earth in Space:
Scientists believe that an earth-like planet must have been very hot and explosive at the time of its formation. It takes about 500 million to 1 billion years for the celestial body to cool down to such a level that inorganic matter can combine to facilitate creation of life.
Possibilities of Life in Space
- The earth was formed like a hot sphere which cooled down in due course of time and an environment was created on it.
- Elements in the atmosphere combined to make simple compounds and eventually to complex compounds.
- These compounds also had some fundamental molecules for life, e.g. water, amino acid and nucleic acid. Condensation of these molecules instantaneously created the first life form.
- There are billions of sun-like stars in our galaxy. Some of them have their own solar systems. There are many earth-like planets, with possibility of life, in many of such solar systems.
The science of exploring the space from earth is called astronomy and when a spaceship of a man is sent into space to carry out research, it is called space technology.
- The first photograph of earth from space was taken in 1946. USSR also jumped in this race in 1947, with the help of German scientists.
- USSR took the initiative and sent the first man-made satellite Sputnik – 1 in October 1957 into space. Sputnik – 1 orbited around the earth while maintaining a distance between 939-215 km from the earth. USSR sent the first animal, first man (Yuri Gagarin), exhibited first spacewalk, landed an unmanned spaceship on a celestial body, and installed the space station named Salute-1.
- The USA tried to win the race by sending the first man on moon in July 1969.
- Today, space research centres of governments of 22 nations are working in this field.
- Loads of Information which we gather about atmosphere and troposphere, with the help of artificial satellites, is not possible to gather from remaining at the surface of earth. The modern telecommunication system is now fully dependent on artificial satellites.
- Spaceships have already been sent on other planets of the solar system, like Mars, Mercury, Venus, Jupiter, Saturn, Uranus and Neptune. American spaceships are orbiting some planets and sending rich information to earth, e.g. Juno (Jupiter), Cassini (Saturn) and New Horizon (Pluto).
- Pioneer 10 was the first spaceship that went beyond our solar system. To rule out the misconception of attack by aliens a plate was fixed on it showing friendly posture of man and woman and a message in sign language stated the real intention of voyage.
India in Space
- The space research in India started in 1948 in the form of Physics Research Institute, Ahmadabad.
- India established Indian National Committee for Space Research (INCOSPAR) in 1962 under the leadership of Dr. Vikram Sarabhai.
- Indian Committee for Space Research was renamed as Indian Space Research Organisation (ISRO) in 1969. ISRO has been at the forefront of developments in space technology since its day of inception.
- India launched its first rocket Rohini-75 in 1969.
- India collaborated with USSR in 1975 and sent its first spaceship Aryabhatta.
- After that India sent two satellites of Bhaskar series; with the help of Russia.
- In 1981, the satellite Apple was sent with the help of Arianne rocket of European Space Agency. This was installed in orbit at a height of 36,000 km from earth.
- India quickly made its own space launch vehicle -3 (SLV 3) which was capable of carrying Indian satellites into space. The first launch of SLV 3 was unsuccessful but after learning from this, scientists were able to successfully send the satellite Rohini into space.
- Indian satellites are helping in transmission of signals for radio, telephone, internet, television, telemedicine, distant education, etc.
India has also been successful in developing Polar Satellite Launch Vehicle (PSLV) which is a powerful rocket. This vehicle can install a satellite to orbit the poles of the earth.
- India has also sent a successful mission to the moon, named Chandrayan. This spaceship orbited the moon and send valuable data. Now, India is planning to send Chandrayan – 2 which would be installed in moon’s orbit and would land a vehicle on the moon.
- Many private agencies have also started taking interest in space. Their main objective is to explore space tourism to earn money.
International Space Station:
International Space Station is an artificial satellite in lower orbit of earth. This is the largest man-made structure in earth’s orbit. It can be seen without a telescope. This is moving on an almost circular path and is maintaining a distance of 330 – 435 km from the earth. It orbits around the earth for more than 15 times in a day. As it was made after collaboration among Japan, Canada, Russia, America and Europe hence the adjective ‘international’ has been used with its name. China is developing its own space station.