The Breakthrough Listen Initiative has released two petabytes of data from the SETI survey of the Milky Way, the most comprehensive survey of radio emissions from the plane of our galaxy, making it available to everyone. Members of the public and scientists alike will now be able to sift through it in search of interesting signals.
SETI stands for Search for Extra-Terrestrial Intelligence, but the observations provide data on much more than just possible alien signals. It provides an important new look at both known and unknown natural phenomena.
This is the second data release from Breakthrough Listen. Last June, the organization released one petabyte of both radio and optical telescope data; the largest release of SETI data at that time. The new release covers both the Northern and Southern hemisphere with observations from the Parkes radio telescope in New South Wales, Australia, and the Green Bank Observatory in West Virginia. The optical observations come from the Automated Planet Finder within the Lick Observatory in California.
"Since Breakthrough Listen's initial data release last year, we have doubled what is available to the public," Breakthrough Listen's lead system administrator Matt Lebofsky said in a statement. "It is our hope that these data sets will reveal something new and interesting, be it other intelligent life in the universe or an as-yet-undiscovered natural astronomical phenomenon."
A particularly interesting analysis performed by scientists in the team before the data release looked at 20 special nearby stars for signs of artificial signals. These stars have a very particular geometry. From their position, Earth can be seen passing in front of the Sun, creating the blip in light we have often used to discover planets passing in front of their star, so if there were any intelligent civilizations out there, they might know that Earth is here and try to communicate with us.
"We didn't find any aliens, but we are setting very rigorous limits on the presence of a technologically capable species, with data for the first time in the part of the radio spectrum between 4 and 8 gigahertz," said Breakthrough Listen principal investigator Andrew Siemion of the University of California, Berkeley. "These results put another rung on the ladder for the next person who comes along and wants to improve on the experiment."
The analysis was performed by Sofia Sheikh, a graduate researcher at Pennsylvania State University, and has been submitted for publication in The Astrophysical Journal. It focused on a very small subset of radio frequencies, so they weren’t really expecting to find a signal like that.
"My search was sensitive enough to see a transmitter basically the same as the strongest transmitters we have on Earth because I looked at nearby targets on purpose," Sheikh explained. "So, we know that there isn't anything as strong as our Arecibo telescope beaming something at us. Even though this is a very small project, we are starting to get at new frequencies and new areas of the sky."
Currently, between 20 and 30 percent of the data has been analyzed, but the team wants to cover all of it multiple times to make sure nothing is missed. This is why it has been made available to the public, and they are asking for help from scientists and coders to data analysts and anyone who has an interest in the quest for alien life to run their own analyses.
“There’s a ton of searching left to do,” Sheikh said. “The best shot we’ve ever had is right now.”