9 Missing Stars Can Not Be Explained By Known Astronomy
Stars shouldn't be able to disappear without a trace. But for the first time in the history of astronomy, researchers have discovered a group of objects appearing and disappearing at the same time. Are advanced civilizations intentionally hiding from our telescopes?
The discovery
70 years ago, a detailed mapping of the northern sky was done for the first time. The Samuel Oschin Telescope in California systematically panned back and forth across the sky, capturing the light of 600 million stars. Everything found with the telescope was preserved on so-called photo discs, but one of the total of 2 000 images stands out.
On the disc from April 1950, nine star-like dots are visible, but on the images of the same part of the sky taken just 30 minutes earlier, they are not there. On the subsequent images taken hours afterwards, the light sources are gone, and although the telescopes have become significantly more sensitive in the decades since the original images were taken, no one has ever seen the nine sources of light in the sky again.
The discovery was made within the framework of the research project VASCO (Vanishing & Appearing Sources during a Century of Observations), which since 2017 has been looking for vanished stars by comparing the old images from the 1950s and 1960s with modern mapping of the sky.
According to astrophysicist Beatriz Villarroel at the Nordic Institute for Theoretical Physics in Stockholm, who leads the project, stars cannot just disappear without a trace. If a star like the Sun were to suddenly disappear, there are two possible explanations for it. Either physics unknown to us caused it to disappear, or superintelligent aliens hid it from our telescopes.
The VASCO and Galileo projects
The primary goal of VASCO project is to search for vanishing and appearing stars (or light sources) using existing survey data to find examples of exceptional astrophysical transients or anomalies.
The Galileo project is a SETI (Search for ExtraTerrestrial Intelligence) project, lead by scientist Avi Loeb at Harvard University, where telescopes and radars will be used to search for signs of extraterrestrial activity that can be seen from Earth. These may be unusual space objects such as the interstellar visitor “Oumuamua” but also objects closer to us.
Although both Galileo and VASCO are interested in anomalies and unusual phenomena, they come in from completely different perspectives. VASCO is a transient project where you do both regular astrophysics with natural astrophysical objects as well as SETI research. In VASCO, public databases are used. Galileo will make new observations in real time, and here the main interest is in solar system SETI and looking for technological signatures from extraterrestrials.
In 2019, the VASCO researchers determined in a scientific article that a total of 100 short-lived light sources in the old images cannot be found today. These are strongly varying objects or phenomena in the sky. Some of these appear in a short time to have increased 8–9 magnitudes, or several thousand times, in brightness.
While it is expected that these anomalies will eventually be explained as natural astrophysical phenomena, there are nine special cases that require more attention, according to Beatriz Villarroel. This anomaly is referred to as the “nine simultaneous transients” phenomenon.
The phenomenon is a group of nine objects appearing and disappearing at the same time within a very short time frame. Could any natural phenomena cause a light source to vanish? And if so, how can nine sources come and go simultaneously?
Dead stars are still visible
For thousands of years, astronomers believed that stars were eternal and unchanging. Today we know that all stars have a life cycle, but their lifespan is long and when a star burns out, it leaves clear traces behind. And the actual death process is usually one of the most violent events that can be observed in the night sky.
Stars like the Sun shine stably for ten billion years. The star then swells into a red giant, which shines for a few million years. Finally, the giant sends its outer layers into space like a nebula and collapses into a small white dwarf star.
The dwarf star is dead to the extent that there are no longer any fusion processes in the core. However, the dwarf is still so hot that it emits both a faint white light and infrared heat radiation, so a dead sun-like star does not disappear.
As for the most common stars in the Milky Way red dwarfs, they have a life expectancy that exceeds the current age of the universe, so the probability of seeing one go out is extremely low.
A “failed supernova” could be a theoretical explanation to why a star disappears without a bang. This is a rare event where a star dies and collapses into a black hole without first exploding as a supernova.
This phenomena was observed for the first time in 2019 when a luminous blue star, that had been observed by astronomers for a decade between 2001 and 2011, suddenly disappeared. Scientists believe that they have witnessed a failed supernova for the first time.
But this is a rare event and in the Milky Way this should happen no more than once every 250 to 300 years. So nine failed supernovas at the same time is not realistic.
Flaring stars are much more common events but nine transients in a very small search box and all within 30 minutes is not realistic. Neither can any other well-established astrophysical phenomena like gravitational lensing, fast radio bursts, or any variable star be responsible for this cluster of fast changes in the sky.
Another possibility is fragmenting asteroids. Could the fragmentation of an asteroid sufficiently far from Earth result in a fragmented shower? Given the constant illumination of the Sun, long streaks are expected due to the orbital motion. Also, had a fragmentation occurred, we’d see a parent body in the blue exposure taken earlier. But there are none.
The team has also considered faint and small meteorite fragments burning up right upon atmospheric entry and shortly “glinting” as they catch fire. The time scale, however, is inconsistent with the observed, longer ablation times for meteorites. Asteroids, meteorites and similar objects cannot explain the simultaneous transients.
What other explanations do we have so far?
The team has also looked for more Earthbound explanations other than astrophysical anomalies.
The glass cover during the plate scanning process is a possible source of contamination. For the more luminous transients among the simultaneous transients, the point sources are more difficult to reconcile with the hypothesis of contamination. However the contamination theory cannot be completely ruled out.
One such theory is about radioactive particles on the photographic plates. In an epoch of time when many atomic bomb tests were carried out in the United States and in the Soviet Union, this is not an unreasonable explanation, as the Palomar Observatory in California is not located far from the testing sites in Nevada.
However, since no official atomic bomb tests were carried between 1949 and 1951 (during the exposure of the plate and during its storage time, since plates were normally developed the same night as the observation), this theory seems unlikely.
The team has also considered airplane lights and other light sources such as fireflies. Airplane strobes can flash fast, but they are also accompanied by continuous lights that leave streaks. There are no streaks present.
Human sources have also been analyzed. Some examples are local events in the observatory such as unusual radio bursts, microwave ovens, humidity, aerosols, water and saliva. But none of these produce consistent circular shapes of the right size.
In conclusion it seems that the nine simultaneous transients phenomena are inconsistent with any well-known natural explanation. Although a natural explanation (such as noise, glitches or contamination) cannot be completely excluded, this discovery opens up for two mind-blowing alternative explanations.
Either physics unknown to us caused it to disappear, or superintelligent aliens hid it from our telescopes.
Unknown natural explanations
Astronomy is changing with the help of computers. Huge amounts of data can be searched to unearth grains of knowledge that would otherwise have been impossible to access. Kristiaan Pelckmans opens up for alternative explanations:
We don’t know what we’re looking for. We look at what is happening at the edge of our knowledge, at what has not yet been explained.
Kristiaan wants to build a new machine that will learn to recognize what is important in astronomical images. This smart machine must cooperate with people — and act as a decision support. The assessment may be based on astronomical knowledge, intuition or just common sense.
It is not difficult to design a machine that can make an accurate judgment most of the time. The difficult thing is to make someone who is always right, he says.
We have much to learn about the Universe and a lot of discoveries to unfold. We still don’t know much about gravity, magnetars and other phenomena in the sky. But AI and machine learning could most certainly help finding the answers.
The non-natural explanations
The scientists in both the VASCO and Gaia projects are carrying the silent hope of discovering something completely new, something unknown. Maybe aliens. According to Beatriz Villarroel it would be a fanciful possibility that there could be beings with technology advanced enough to move, obliterate, or hide an entire star.
An alien megastructure such as the Dyson sphere could block all wavelengths of light equally. A Dyson sphere (also known as Dyson swarm, Dyson bubble, Dyson ring) is a system of orbiting megastructures designed to intercept and collect all energy produced by a parent star.
Dyson spheres came to the fore in 2015 in connection with a strange star whose brightness decreased in a way that was difficult to explain. The star is often called Tabby's Star. Today, almost no one believes that extraterrestrials have a hand in the game when it comes to this particular star - rather they talk about comets or dust clouds. But the reasoning about megastructures was widely spread.
Another option is alien laser flashes. It has long been speculated that powerful lasers might be used by advanced civilizations for interstellar communication. Messaging by light has a fundamental advantage over radio in that it can convey much more data per second — typically a half-million times as many.
This increased bandwidth is a characteristic that would make lasers useful for communicating between alien colonies. Powerful lasers can also propel spacecraft to near-relativistic speeds and could conceivably be in widespread use for this purpose.
Yet another explanation could be huge starships moving through space. In this case they would not be missing, but rather moving.
But none of the above could really answer the nine simultaneous light sources, unless they are located very close to each other.
Beatriz Villarroel summarizes her thoughts on alien civilizations as an explanation by quoting science fiction author Arthur C. Clarke:
All sufficiently advanced technology is indistinguishable from magic
