Space News & Blog Articles

In 1977, the Big Ear Radio Telescope at Ohio State University picked up a strong narrowband signal from space. The signal was a continuous radio wave that was very strong in intensity and frequency and had many expected characteristics of an extraterrestrial transmission. This event would come to be known as the Wow! Signal, and it remains the strongest candidate for a message sent by an extraterrestrial civilization. Unfortunately, all attempts to pinpoint the source of the signal (or detect it again) have failed.

This led many astronomers and theorists to speculate as to the origin of the signal and what type of civilization may have sent it. In a recent series of papers, amateur astronomer and science communicator Alberto Caballero offered some fresh insights into the Wow! Signal and extraterrestrial intelligence in our cosmic neighborhood. In the first paper, he surveyed nearby Sun-like stars to identify a possible source for the signal. In the second, he estimates the prevalence of hostile extraterrestrial civilizations in the Milky Way Galaxy and the likelihood that they’ll invade us.

Almost fifty years after it was detected, the Wow! Signal continues to tantalize and defy explanation. In recent years, attempts have been made to attribute it to comets at the edge of our Solar System, an explanation that the astronomical community has since rejected. In 2020, interest in this candidate ETI signal was revitalized when Cabellaro identified a Sun-like star in the vicinity of the sky where the Wow! Signal was detected. If the analysis is correct, this famous signal may have come from a Sun-like star located 1,800 light-years away.

The recap, the Wow! Signal was detected by the now-defunct Ohio State University Radio Observatory (nicknamed “Big Ear”), which was assigned to SETI surveys in 1973 after completing an extensive survey of extragalactic radio sources. In the summer of 1977, astronomer Jerry R. Ehman was working as a volunteer with the project and was tasked with analyzing the massive amounts of data printed on line paper. On August 15th, he spotted a series of values indicating a massive intensity and frequency boost.

Ehman circled the alphanumeric designation for this signal (6EQUJ5) and wrote “Wow!” next to it. In recent years, coinciding with the 35th anniversary of the signal’s detection, there has been renewed interest and research into this mysterious event. This should come as no surprise, considering how it remains the most likely candidate for an extraterrestrial message. Despite being (from all accounts) an unmodulated continuous wave, there were several indications at the time that the signal was not natural in origin.

In this age of exoplanet discovery, we’ve discovered thousands of exoplanets of different types. The hot Jupiter is one of the most unusual types. There’s nothing like it in our Solar System.

Hot Jupiters are massive gas planets, and they attract a lot of attention because they’re so close to their stars and reach blistering temperatures. Their existence spawns a lot of questions about their formation and evolution. A new study is trying to answer some of those questions by determining hot Jupiters’ ages.

Hot Jupiters are the most easily-detected exoplanets because they’re so close to their stars and orbit so rapidly. That means they transit often and cause a relatively large dip in starlight when they do. 51 Pegasi b was the first hot Jupiter found, and astronomers spotted it orbiting a Sun-like star in 1995. Now we know of at least 400 hot Jupiters.

Scientists have studied this unusual class of planets and learned a few things. They’re usually tidally locked, and the dayside-nightside temperature difference can reach 1000 Kelvin (726 C) or more. They’ve discovered that hot Jupiters have thermally inverted atmospheres due to the presence of elements like iron, titanium, and vanadium. They’ve also found less water than expected, raising questions about their formation. Hot Jupiters appear to be more common around stars with higher magnitudes like the Sun and less common around low magnitude stars like red dwarfs, although observational biases may play a role there.

How these planets form is a central question in exoplanet science. Do they form like other planets and then migrate towards their star while the star is still young? Or do they fully form further away and migrate later in life in a process astronomers call high-eccentricity migration?