The Search for Extraterrestrial Intelligence (SETI) is said to be probing a signal coming from the Hercules constellation, which is believed to have been sent by an alien civilisation much more advanced than us.
The signal was first detected on May 15, 2015 by a Russian receiver, and is said to be coming from near a star designated HD164595 that is 95 light years away and 6.3 billion years old. Compared to that, our own sun is 4.6 billion years old. However, both stars are believed to have a similar chemical composition, including percentage of metals, which has raised hopes of the existence of a Kardashev Type II civilisation there.
The Kardashev scale — named after Soviet astronomer Nikolai Kardashev — is a scale used to categorise civilisations. A Type-I civilisation is one that harnesses only that energy from its nearest star that it receives directly. Humankind is in this category. A Type-II civilisation on this scale is one that harnesses the nearest energy from its nearest star. This is the kind of civilisation that could be behind this signal.
What has also bolstered this hope is that the signal is believed to be coming from an isotropic beacon — one that can send signals of equal length in all directions, and which exist on Earth only as a hypothesis. Such a signal, to be transmitted in all directions, so that wherever it is received it gives the same power reading, requires a huge energy source, which can only come from an entire star.
The only planet near where the signal is coming from is comparable to our own Neptune in size, but much warmer. It is designated HD164595 b, but there could be more planets around the star HD164595, which we have not discovered yet.
Meanwhile, comparisons are already being drawn between this signal and the narrowband radio signal detected by a radio telescope in the United States in 1977. The unusually strong signal was detected by the telescope for the full duration of 72 seconds over which it was focusing on that direction. It came to be known as the "Wow! signal" because astronomer Jerry R Ehman, who was monitoring the telescope then, marked the signal in a red boundary and wrote the word "Wow!" beside it.
