A new study shows aliens might live only 33,000 light-years away. Read on to know why we haven’t found them yet.
There are signs of the possibility of intelligent alien life all around our universe.
Billions of galaxies drift through the visible cosmos, each one containing hundreds of billions of stars, and each of those stars in turn shelters many planets. These trillion-or-so planets in every galaxy may not be habitable but the countless moons orbiting these lifeless spheres might be.
However, despite the vast number of planets, humans have yet to discover life beyond earth. Even after many types of research, the question is remains unanswered – Are we alone in this universe?
The searches for extraterrestrial intelligence, or SETI, suggest that somewhere in that ocean of space, within the Milky Way galaxy, intelligent aliens may be out there trying to make contact and we’d have no way of knowing, at least not yet.
Multiple SETI projects have looked over the past 60 years, and continue to look for alien signals. Some scan the sky for powerful signals, while others target individual star systems for weaker signals. Yet, these searches have turned up empty-handed.
Even though it might be similar looking to looking for a needle in a haystack, the group of SETI is determined to find the “needle”. They agree with the well-known SETI astronomer Jill Tarter, who said in 2010 that it was pointless to conclude intelligent aliens do not exist nearby just because we haven’t yet found their signal. According to Jill, such may signal to exist and are aimed right at Earth, but we have not yet to scan the whole sky and may not be looking for the right type of signal to find them.
In their study, the group of colleagues built a mathematical model of what they considered a reasonable-size “cosmic haystack”, which was a sphere of space nearly 33,000 light-years in diameter, centered on Earth. The region captured parts of Milky Way’s bustling core as well as some giant globular clusters of stars above and below our galaxy.
They also picked eight dimensions of a search for aliens — factors like signal transmission frequency, bandwidth, power, location, repetition, polarization, and modulation, defining reasonable limits for each one.
They concluded this led to a total 8D haystack volume of 6.4 × 10116 m5Hz2 s/W – that is 6.4 followed by 115 zeros — which was described as “a space of truly gargantuan proportions.”
The group then examined the past 60 years’ worth of SETI projects and reconciled them against their haystack. This helped them determine that humanity’s collective search for extraterrestrials added up to about 0.00000000000000058% of the haystack’s volume, which is about a bathtub of water in all of Earth’s oceans or a five-centimeter-by-five-centimeter patch of land on all of Earth’s surface area. That may make humanity’s search efforts seem meager.
However, modern telescopes are getting better at scanning more objects with greater sensitivity and speed. For example, a 150-minute search this year by the Murchison Widefield Array covered a larger percentage of the galaxy than any other SETI project in history.
Still, there’s no guarantee of alien civilization so far.
On the other hand, a group of scientists from Oxford University recently took a different approach to the question of aliens. Rather than focusing on the likelihood of finding techno signatures that could be detected, they questioned the likelihood of intelligent alien life exists at all.
These researchers examined dozens of authoritative studies about variables in the Drake equation. Then they analyzed the results and calculated a dreary 2-in-5 chance that humans may be entirely alone in the Milky Way galaxy.
All being said, there is also a more unsettling possibility – could it be that aliens do exist nearby but don’t want us to find them?