Summer is here! It’s the perfect time to get out and indulge in activities that are not part of your routine, like visiting the planetarium to understand the world beyond Earth’s Exosphere.
Amazing
The Nehru Planetarium in Mumbai has launched its new show titled “Invaders of Mars”. There are movies about alien invasion, speculations about the existence of extra-terrestrial life forms and rumoured UFO sightings… But here is one instance where we humans have actually “invaded” Mars with our satellites, landers, rovers and orbiters, purely out of curiosity and a desire to learn.
It begins with a description of how until 1965 our understanding of Mars was coloured by the observations and conclusions of one scientist — astronomer Percival Lowell, who set out to study the planet from his observatory at Mars Hill, Flagstaff, Arizona, U.S. for over 15 years.
He observed lines of vegetation planted on the banks of giant canals, which he believed brought water from the melting poles to irrigate the planet’s vast deserts. This he imagined was built by an intelligent race of Martians. And many believed him!
It was only post-1965 beginning with Mariner 4 spacecraft which flew past Mars and revealed a barren, desolate planet with freezing temperatures and an extremely thin atmosphere. No sign of Martians! Six years later, this was confirmed by the space orbiter Mariner 9. It was the first artificial satellite of Mars and it showed a planet whose features were formed by dark dust and strong winds, craters like mud splats, features that looked like dried-up river beds and a vast canyon.
Every mission to the red planet enabled us humans to understand our neighbour better:
Traces of methane were detected in the atmosphere indicating that volcanic activity or even primitive life forms exist today.
There are landscapes hidden beneath the surface terrain. Radio waves have penetrated the bedrock to reveal traces of vast water ice deposits covering large areas of the planet.
There was evidence of sudden and sometimes catastrophic water flows. Abrupt melting of the underground ice either by volcanic activity or meteorite strikes could be the cause.
The ice consists of layers of frozen water and carbon dioxide. Surface ice exists at the Martian poles. Measurements show that at the southern pole there is sufficient water ice to flood Mars to a depth of over 30 feet.
In 2008, the Phoenix spacecraft observed the snow fall on Mars at temperatures of -65° centigrade. It found chloride, bicarbonate, magnesium, sodium potassium, calcium, and possibly sulfate in Martian soil.
Further south, especially during summer, the temperature can be quite balmy at 50°.
The presence of silica suggests that hot water springs once existed. On Earth, such springs harbour primitive life. What about Mars?
The show playing at the planetarium is a prelude to the ISRO’s Mars mission. In November 2013, ISRO will launch a 1.4 tonne Martian spacecraft using a high-end rocket PSLV-XL, from the Sriharikota spaceport. It will have nine instruments to study various aspects of the red planet. The mission will explore Mars’ atmosphere and search for life-sustaining elements.
