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| Are We Observed By Aliens |
Are we alone in this universe? This existential question may have arisen in everyone's mind. Considering the vastness of our universe and the vast number of star systems it contains, we may not be alone! And if so, what if an alien civilization, millions of years ahead of us in technological advancement, has already found us? What if these aliens are hiding in our solar system? If we are constantly portrayed and watched by them? Is it possible that there are aliens lurking in our solar system? In this video we discuss whether any alien civilization can see us or not! If you're here watching this video, it means you're passionately curious about human spaceflight and the mysteries of the universe.
In 1950, Enrico Fermi asked a question.
"Where's everyone?"
The question became one of the most famous paradoxes in history, also known as the Fermi Paradox. There are billions of stars in our universe and trillions and trillions of planets in those stars. Considering the large number of planets that exist in our universe, the chances of finding life are very high. So if that's the case, then the universe shouldn't be filled with spaceships. Where is everyone? This is the Fermi Paradox and no one has a real answer. What we have are possible theories and among them is a theory that says that advanced aliens are hiding in our solar system and watching us.
Are aliens taking pictures of us right now watching us go about our day, silently observing our behavior. It can send chills down your spine and make you wonder about the science behind this theory. Is it really possible? Can anyone really observe us without us noticing them? Aliens would need the technology to take long-distance pictures of space to see us. The fundamental challenge in imaging other star systems is the distance between them.
Even our closest stars are so far away that they appear as specks of light. Today in modern astronomy we have developed various techniques to identify and discover planets orbiting other star systems. To date about 5000 exoplanets have been discovered by various techniques used by us. This image of the young star system, PDS-70, is a state-of-the-art image taken by the Alma Observatory last year. Despite this technical achievement here, the Jupiter-class spatial resolution in this image is very limited, and anything smaller than that cannot be resolved by us today.
This is why a Jupiter-type planet appears as just a puff of smoke. Even if the image of the planet was resolved by a scale of 1000, we would still only have a best image of 1 by 1 pixels. So you can only imagine what kind of resolution would be needed to image and observe a planet as small as Earth. On top of that, the ALMA Observatory was able to detect this planet because it was recently formed and the light we see is very hot and bright.
Compared to this planet in PDS-70, our Earth is not only too small, but too faint. To deal with these two problems of resolution and faintness, the only common solution is to build a very large telescope. Fortunately in 2010, Gene Snyder and his colleagues calculated the extreme limits of our technology, saying that to take a 10 by 10 visible light image of a supersized Earth that's only 16 light-years away, we'd need a 70-km-wide telescope.
Now we don't necessarily need a single telescope 70 km in diameter, we can use a technique called interferometry, which uses several telescopes to pick up light scattered over a 70 km area. This concept was taken to the extreme by the Event Horizon Telescope (EHT) which used telescopes around the world to famously image the bulk hole in Messier 87, the first image of a bulk hole! But even using the whole Earth as a visible-light interferometer still wouldn't be enough to resolve exoplanets, so that we could see those planets' inhabitants.
This will be the ultimate goal of exoplanet observation. Imagine a video of a distant exoplanet, so detailed that you can easily see the planet's alien flora and fauna. We can see the sentient beings of the planet going about their days. The potential insights from such a video can be truly amazing. Snyder calculated that you would need a telescope the diameter of the Sun to get this level of detail.
But that would only solve the resolution problem, we also need photons from those distant exoplanets. So even with such a large telescope it would be almost impossible to image the inhabitants of those planets because they would be so faint that even their photons would not reach us. We have taken the time to explain this to you because the aliens will need this technology to observe us from afar and even that will not be enough!
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| Hubble Space Telescope |
The Hubble Space Telescope is one of the most important telescopes for mankind, providing thrilling images of the universe. With a diameter of 2.4 meters, Hubble travels 540 kilometers above Earth, 75 billion times farther than the nearest star, Proxima Centauri. But if we were to turn the Hubble telescope to look at people on Earth, the spatial resolution provided by Hubble would be enough to see people through their days. This means that while it's possible to solve a planet's inhabitants from space, you'll probably need to go to that star system.
This brings us to the title of this video, What if they are hiding in our solar system? Mission concepts such as Breakthrough Starshot are to visit and observe distant planets. Given the limits of our telescope, this will be the ultimate goal of observation. Given that we are curious about doing this, what if an advanced alien civilization has already done this to us. First proposed by Ronald Bracewell in 1960, the idea suggests that we should look for probes inside our solar system rather than listening for radio signals from distant stars.
These are called Bracewell probes and could observe Earth for millions of years if intelligent life develops. Earth has been presenting a clear oxygen biosignature for about 2 billion years now. These Bracewell probes can even harness their energy to the Sun and send information about us to their home planet.
As sci-fi as this idea sounds, let's frankly explore the science behind it. So the tools we use today to look for signals from distant stars can easily be repurposed to look for these probes and signatures in our own solar system. And imagine if we could eavesdrop on the infections created by these hidden probes. These transmissions may have a layer of encryption, but it would be exciting if they weren't made for us. We can't help but wonder what the transmission says, what compression algorithm it uses.
All these things will be completely alien to us, their language, the mathematics they use! Unless the aliens deliberately want to decipher these messages and provide us with simple data forms, they need not worry about their privacy and encryption because all information will be completely foreign to us. The mere presence of such a find in our own backyard would be huge for what we could possibly salvage and reverse engineer. But where in our solar system will this probe be to quietly and easily observe us? Where should we look for them?
Let's talk about the science behind it. If this probe is to take clear high-resolution images of Earth, it needs to be as close to Earth as possible. Low Earth Orbit or LEO is the perfect place for him! But it has already been closely observed by humans. US space surveillance catalogs more than 34,000 objects in orbit around Earth, as small as 10 centimeters in size. A probe smaller than this would be unable to resolve human behavior on Earth, so this possibility is out of the question.
The presence of a low Earth orbit lurker will be challenged by our extensive observations in this region. The next place we can see is our moon. A probe on the Moon would have completely stable gravity and would be undisturbed by atmospheric erosion, weather or any geological activity. However, almost every part of our Moon, like low Earth orbit, has been extensively photographed by orbiters over the past few decades.
The Lunar Reconnaissance Orbiter imaged the surface of the Moon at a spatial resolution of 100 meters. So if there was a 100 meter sized alien telescope on the lunar surface we would have seen it by now or it was too small. Much more than that would be required to depict the Earth's surface in order to observe its inhabitants. So when the moon comes out, there are more questions? Co-orbital asteroids and quasi-satellites may be our next best hope.
A particularly interesting prospect in Cruthon! It is a two-kilometer-sized co-orbital asteroid that follows a horseshoe orbit that takes it as close as 12 million kilometers to Earth once every 770 years.
Even if this asteroid were some kind of giant extraterrestrial telescope monitoring the entire two kilometers of Earth, it would still be limited to a spatial resolution of no more than four meters on Earth's surface, and it would only be this rare and occasional occurrence. Duration of the nearest procedure. And that's not really enough.
However, Kreithon is one of the few other co-orbitals. If these different asteroids form an interferometric network. These co-orbital objects are thought to be stable over thousands of years, but not millions, and they move in unpredictable, almost chaotic orbits with each other that make interferometry a nightmare. The extraterrestrial hidden within this co-orbital is not a clear and obvious alternative or alien.
With Earth's orbits and co-orbitals being unstable, there are many significant difficulties, it is possible that lookers will choose more distant vantage points where Earth's gravity will not destabilize their probes. But that would require a truly massive space probe, for example, to visually image Earth at one meter resolution from a vantage point close to Saturn's distance, would require a telescope roughly the size of our Moon.
Of course, aliens could use interferometric methods but now the huge survey area would have to be swept and the sheer faintness of these probes would make them currently unobservable. Taken together, it is highly unlikely that there is an unknown alien lurker imaging the Earth at high resolution and at visible wavelengths. But anything can happen. So what do you think about the possibility of aliens visiting us? Are they interested in creating such an over-engineered system to monitor us? More updates on these extraterrestrial beings will come from both SETI and METI.
So make sure you follow our website and don't miss all the interesting updates about astronomy and space flight.