Communications throughout the vastness of interstellar room could be enhanced by taking benefit of a star’s ability to concentrate and magnify communication signals.
A team of graduate student students at Penn Condition is looking for just these sorts of communication signals that might be taking advantage of our own sun if transmissions had been passing through our pv system.
The paper describing the technique— explored as part of a graduate course at Penn State covering the Search for Extraterrestrial Intelligence (SETI)— has been accepted just for publication in The Astronomical Journal and is available on the preprint server arXiv.
Massive objects like stars and black holes result in light to bend because it passes by due to the object’s gravitational pull, according to Einstein’s Theory of General Relativity. The warped space throughout the object acts somewhat just like a lens of a telescope, focusing and magnifying the light— an effect called gravitational lensing.
“ Astronomers have considered taking advantage of gravitational lensing as a way to essentially create a giant telescope to look at exoplanets around other stars, ” said Jason Wright, professor of astronomy and astrophysics at Penn State who else taught the course and is director of the Penn Condition Extraterrestrial Intelligence Center. “ It has also been considered as a means that humans might get in touch with our own probes if we actually sent them to another star. If an extraterrestrial technological species were to use the sun as a lens designed for interstellar communication efforts, we should be able to detect those marketing communications if we look in the right place. ”
Since communications across interstellar distances would face a variety of problems related to transmission power plus fidelity across such vast expanses, the researchers think any communication efforts would likely involve a network associated with probes or relays, such as cellular telephone towers in space. In this study, these people looked to one of our closest stars, which should be the closest node in a communication network.
“ People use networks to connect across the world all the time, ” stated Nick Tusay, a graduate student student in the course exactly who helped lead the task. “ When you use a mobile phone, the electromagnetic dunes are transmitted to the nearest cellular tower, which connects to the next tower and so on. TV, radio, and internet signals also make the most of network communication systems, that have many advantages over point-to-point marketing communications. On an interstellar scale, it seems sensible to use stars as lens, and we can infer exactly where probes would need to be located in order to use them. ”
In this study, the researchers looked more than 550 times the Earth-sun distance opposite the sky through Alpha Centauri— the closest stars to our own system that might be the nearest client in a communications network— that is where a probe would be situated in our solar system in order to use the sun as a zoom lens. This enabled the researchers to potentially detect radio transmissions that might be signals sent directly to Earth to communicate with us, signals being sent to various other probes exploring the solar power system, or perhaps even indicators being sent through the gravitational lens back to Alpha Centauri.
“ There has been a few previous searches using optical wavelengths , but we chose to use radio wavelengths , because radio is a great way to communicate information across space, ” said Macy Huston, a graduate student in the course who helped lead the project. “ We all included what is known as the ‘ waterhole’ wavelengths, which are often the focus of SETI searches because they would be an ideal part of the radio spectrum to connect in and could act like a waterhole on Earth, where several species convene. These wavelengths are generally free from other stereo waves coming from cosmic objects, so it’s a clean part of the spectrum to communicate within. ”
Looking into these particular wavelengths also allowed the researchers to maximize the amount of data they could collect over the sky in a short screen of time. The student experts collected the data over 1 night when they visited the particular Green Bank Telescope within West Virginia. Their data collection and analysis were conducted in collaboration with Breakthrough Listen, a program dedicated to finding evidence of intelligent life beyond Earth.
The particular students did not detect any kind of signals in the wavelengths they investigated that might be of extraterrestrial origin in the area they observed, recommending that signals at these types of wavelengths were not being sent towards Earth during the short window when they were looking.
“ Our own search was limited to one night, so anything that wasn’t broadcasting while we were observing was not going to get acquired, ” said Tusay. “ Although our limited search could miss existing probes if they weren’t constantly transmitting at these frequencies, it was a good test to see if this kind of search is possible. ”
The researchers suggest that extending their search to include additional observations, or observations directed at other nearby stars or other frequencies, could still prove productive. One of the students in the course is currently exploring archival information to see if previous Breakthrough discovery Listen observations have directed at additional areas that could be optimal for probes utilizing the gravitational lens effect.
“ The lensing effect isn’t the most robust at these frequencies, though there are still good reasons these frequencies might be used, ” mentioned Huston. “ But all of us believe the technique is certainly sound and hope that students in the course in future years might expand on this search. ”
The graduate-level SETI course is one of only 2 in the world— the other on the University of California, Mis Angeles— that encourages graduate student students to conduct a radio-based SETI research project and to publish their results in a scientific journal.
“ This graduate training course is the centerpiece of the Penn State Center for Extraterrestrial Intelligence, ” said Wright. “ Students come from a number of disciplines, including astrobiology, astronomy, chemistry, and geophysics. This year, because it was a hybrid course, we even had a college student from another university sign up for us. One of the neat things about this class is that, because the SETI field is so youthful, it is possible for students to produce a real contribution and publish research. It’s remarkable. ”
The research was presented June 29 at Penn State’s 1st SETI Symposium in State College, Pennsylvania.