We often hear the phrase “speed of light” think about increased acceleration. This is because light typically travels about 240,000 miles from the moon to the Earth in seconds. But did you know it can also be slowed down?
In 1999, Lene Hau, a Harvard physicist, was able to slow down the speed of light to 17 meters per second. Practically the speed of a car during rush hour traffic. By 2001, she was able to stop light completely.
How Was This Possible?
Hau was able to alter the speed of light by discovering an entirely new state of matter. When atoms are tightly packed together at low temperatures within a high vacuum space, they lose their identity as individual particles. Instead, they mold together and start acting like a single super atom.
In this odd state of matter, light takes on a more human dimension; you can almost touch it.
Lene Hau
Hau was the lead scientist on the experiment, which was done at the Rowland Institute of Science. Other members of the team included; Zachary Dutton, Cyrus Behroozi, and Steve Harris. (Source: Harvard)
Why Did They Study This?
The primary reason was sheer curiosity about the new state of matter. During the process, they were able to identify several practical uses for slowing light which included creating new laser types and the ability to transmit data, pictures, and even sound with less power and space.
We did them because we are curious about this new state of matter. We wanted to understand it, to discover all the things that can be done with it.
Lene Hau
Building the container for the new matter took several years for Hau’s team to build. This was preceded by series of long-hour trial runs to make sure that all the parameters were working correctly. (Source: Harvard)
How Did the Experiment Go?
Hau’s study proves that the speed of light can be altered. The results of the experiment were more than just positive.
So many things have to go right, but the results finally exceeded our expectations. It’s fascinating to see a beam of light almost come to a standstill.
Lene Hau
(Source: Harvard)
Was This the First Time Anyone Attempted to Study a New Form of Matter?
The quick answer to this question is no. The idea of a new form of matter was first brought up in 1924 by Albert Einstein and Satyendra Nath Bose. As per their theory, when the atoms come close enough to each other under low temperatures, they lock. This is what Hau termed as a single glob of matter that produces waves.
Despite this theory being around since the 20s, it wasn’t actually until 1995 when this was actually made. The Bose-Einstein condensate was way ahead of its time. They just needed the right technology to make it possible. (Source: Harvard)
How Can This Technology Help in Our Daily Life?
While slowing down the speed of light this way does not directly violate any principle in physics. According to the theory of relativity, nothing is altered.
However, slowing light can certainly help our understanding of the bizarre state of matter of a Bose-Einstein condensate. Technologies that push past old limits are always expensive and impractical to begin with; then they become cheaper and more manageable.
Lene Hau
(Source: Harvard)