Universe is not only Expanding but Accelerating

Image : Astronomers use changes in brightness of Cepheid star to measure distance

Credit : NASA/ESA Hubble Space Telescope

 

     We know that our universe is expanding every second.In 19th Century Edwin Hubble discovered the rate of expansion of the universe and that was called Hubble Constant, which is essential for determining the age,size and fate of Cosmos. Before the launch of Hubble Space Telescope, the values of astronomical measurement was calculated using Hubble Constant.The age of the Universe was estimated as 10 billion to 20 billion years. But the modern astronomers were able to determine accurate values using Hubble Telescope.[For example: the distance between stars is calculated using brightness of stars]. With Hubble's refined values, the present age of the Universe is 13.8 billion years.

     With all the observations from Hubble and Ground based observation, astronomers have found that the universe is not only Expanding but Accelerating. This new discovery led to won 2011 Noble Prize in Physics.

     Scientists believe that the acceleration may be the cause of "Dark Energy" which is a thought of Anti-gravity. This Anti-gravity pushes the galaxy by stretching space at an increasing pace. Till now Dark energy is an unsolved mystery. Astrophysicist believe that 70% of the Universe is composed of Dark matter which cannot be measured or seen through modern technology. Scientist will get better understanding about the Universe if they solve dark energy mystery.