- Education and Science»
- Astronomy & Space Exploration
Company of earthlike planets
billions of extrasolar / earthlike planets are there
Milky way galaxy is one of the oldest galaxies and is estimated to be 13.2 billion year old, almost as old as the Universe itself @ 13.7 billion years. The no. Of stars is estimated to be 100 billion to 400 billion. Many of them are invisible red dwarf stars nearing the end of their life cycle. A large no of such stars are expected to be hosting at least one or two extrasolar planets. Somehow these red dwarf stars are found to be favourite candidates for such activity as the warmth and radiance from the red dwarf is just adequate for a planet to be in a comfort zone easier to develop than a normal star.
The assumption about such red dwarf stars is found to be correct by HARPS planet finder of ESO. It confirms that earthlike planets are quite abundant around many stars so much so that there is a planet on average for every star. Red dwarf stars of milky way are holding many such planets. There could be at least 200 billion stars with abundance of other live factors. 80% of milky way galaxy stars are red dwarf stars and obviously at least 160 billion extrasolar planets should be crawling in our own milky way galaxy. Further assuming that only 5% of them are like ours, there are 8 billion planets.
HARPS team leader Xavier Bonfils (IPAG, Observatoire des Sciences de l’Univers de Grenoble, France) further augments these earthlike planet nos. To 40 billion with variable sizes in zones where liquid water can exist The conclusion had been carefully arrived at based on empirical observations of various stars and red dwarf stars in particular. The study had been further augmented by a sample survey by the team on 102 red dwarf stars wherein 9 super earth planets (one to ten times the size of the earth) were located. Very terrestrial planets in the orbit of Gliese 581 and Gliese 667 C with abundance of water could be located.
The same study concludes that the Sun has several red dwarf stars in the neighborhood of 30 light years. Probably we have company in the form of Earthlike planets in hundreds within this radius.
HARPS survey puts limelight on Gliese 667 Cc right in most habitable zone. With size 4 to 5 times bigger than earth, its anybody’s guess what kind of life is supported by the planet.
HARPS research opened up new vistas for extrasolar planet research with special focus on planets resembling earth. We need not focus on entire arms of milky way galaxy stated to be as long as 30000 light years but on small fraction of 30 light years itself.
With exciting news from HARPS, Kepler mission and Hubble Telescope pouring in, astronomers the world over are excited about discovery and broadcast of advanced alien life in our galactic neighborhood itself. One NASA Scientist Dr. Kailash Sahu holds a record for discovering maximum no. Of extrasolar planets. He is emphatic that life must be very common among them as all other life supporting chemicals such as water, methane and Sodium have been found!
Today’s youth are blessed as several mysteries unravelling in the cosmos on alien life and planets similar to ours will enrich their lives. I propose to summarise this article on the observation that rather incredible distances within our own galaxy with each arm spreading thousands of light years disable us to establish a contact with these alien civilisations for some more decades! Perhaps that would be the best option available in terms of advice offered by Stephen Hawking.