Buzz
The vastness and mystery of space is beyond imagination. It's doubtful that we'll ever fully explore it before humanity's time comes to an end. However, now and then, we stumble upon strange celestial objects or witness unexplained phenomena.
Answers to these cosmic riddles are rarely clear. Most of the time, we can only speculate on what they might be. Yet, some anomalies are so extraordinary that we’ve considered them as potential proof of intelligent life elsewhere in the universe.
10. Oumuamua
In October 2017, astronomers discovered a strange object drifting through our solar system. They named it Oumuamua. It passed close to the Sun, coming within a quarter of the distance between Earth and the Sun, before suddenly accelerating and leaving our solar system.
The nature of Oumuamua and the reason behind its unexpected acceleration remain unknown. Some astronomers propose that it could be an unusual comet, while others suggest it might be an asteroid, a half-formed planet, a solar sail, or even a giant piece of ice that separated from a shattered planet.
Shmuel Bialy and Avi Loeb from Harvard University hypothesize that Oumuamua is a solar sail, a spacecraft powered by sunlight. They believe it could have been constructed by extraterrestrials to explore our solar system.
Yet, other astronomers disagree with this theory. Zdenek Sekanina of NASA argues that Oumuamua is an icy comet without a tail, suggesting that it lost the water and gases that would have formed its tail when it ventured too close to the Sun.
Gregory Laughlin and his team at Yale University concur that Oumuamua is made of ice, but they do not think it’s a comet. They theorize that it could have once been part of an icy planet destroyed after getting too close to a larger planet.
Amaya Moro-Martin from the Space Telescope Science Institute believes that Oumuamua could be the remnant of a planet that was still in the process of forming. She and her team theorize that this planet was ejected from its star system before it could fully develop. If true, Oumuamua would be the first partially formed planet ever discovered.
9. Tabby’s Star
In 2011, scientists analyzing data from NASA’s Kepler spacecraft found that a star named KIC 8462852 often dimmed before brightening again. This star is also called Boyajian’s star or Tabby’s star.
Several theories were proposed to explain this strange phenomenon. Some researchers suggested that the dimming was caused by a group of comets orbiting the star or other unidentified materials in our solar system. Others believe the dimming could be the result of dust surrounding a black hole between Tabby’s star and Earth.
A group of astronomers initially speculated that the dimming effect might have been caused by a massive structure built by intelligent beings. They proposed that the star's light was blocked as an orbiting megastructure passed between the star and the Kepler space telescope. This hypothesis sparked great interest, prompting other scientists to investigate the true cause of the dimming event.
When the star dimmed again in May 2017, dozens of telescopes were used to observe it. Scientists quickly ruled out the megastructure theory, as such an object would block all colors of the star's light, not just cause a dimming effect. They concluded that the dimming was likely due to space dust orbiting the star.
Despite this, scientists were unable to determine the source of the dust or confirm its exact nature. It also appeared as though the dust was being blown away from the star. This led some researchers to speculate that an unknown celestial body could be generating more dust that orbits the star.
In 2016, Brian Metzger from Columbia University proposed that the dust might have come from a planet or moon that was destroyed after getting too close to Tabby’s star.
8. FRB 121102
Fast radio bursts (FRBs) are powerful radio signals that we rarely receive from space. While scientists haven't pinpointed their exact origin, it's believed that they may be emitted by exploding stars or neutron stars being consumed by black holes. These bursts tend to vanish just as quickly as they appear, but FRB 121102 is an exception.
Since the first signal from FRB 121102 was detected on November 2, 2012, scientists have received over 150 signals from this source. They've traced the signals back to a distant galaxy located three billion light-years away, though the specific source remains unidentified.
One theory suggests that the signals could be coming from a neutron star. Another possibility is that the FRBs are being emitted by technology used by aliens to power their spacecraft. However, scientists don’t believe that these signals were intentionally sent to contact humanity, as they originated three billion years ago, when Earth was still home to only single-celled organisms and humans did not yet exist.
7. The Dark Flow
Astronomers have discovered a cluster of distant galaxies speeding through space at over 1.6 million kilometers per hour (1 million mph). The reason for their extraordinary velocity and their ultimate destination remains a mystery. This unexplained motion has been dubbed “the dark flow.”
Scientists suspect that the dark flow is being caused by a massive, yet undetected celestial object that is pulling the galaxies toward it. While the galaxies are currently moving away from Earth, researchers cannot rule out the possibility that this motion could reverse, causing them to move toward Earth in the future.
6. The Cow
In June 2018, a sudden, bright flash appeared in the Hercules constellation, located 200 million light-years away. This flash was so intense that its brightness was equivalent to that of 10 to 100 supernovae. The event was named AT2018cow, or 'The Cow.' It remained dazzling for two weeks before beginning to fade.
Scientists analyzed the X-ray and ultraviolet radiation emitted by the flash and determined that it was caused by a black hole consuming a white dwarf. (A white dwarf is the remnant of a small star after it dies.) However, some scientists believe that the event, known as The Cow, was actually triggered by a black hole or neutron star formed from the death of a star.
5. A Strange Signal From A Sunlike Star
On May 15, 2015, astronomers using the Russian RATAN–600 telescope detected an unusual radio signal from a star similar to the Sun, located 94 light-years away. The star, named HD 164595, shares many similarities with our Sun, such as chemical properties and temperature. However, HD 164595 is 1 percent lighter and about 100 million years younger than the Sun.
Some astronomers speculate that the strange signal might have come from aliens, as the star system housing HD 164595 is known to have a Neptune-like planet, HD 164595 b. Scientists believe the system could harbor other, yet undiscovered planets, possibly even an Earth twin.
However, other scientists are skeptical that the signal is extraterrestrial in origin. For one, the astronomers who initially detected the signal kept it under wraps for an entire year. Additionally, the unique construction of the RATAN–600 telescope makes it challenging to pinpoint the precise location of the signal. Therefore, the HD 164595 system might not be the actual source of the signal.
Moreover, for the signal to be sent by aliens, they would have needed at least 50 trillion watts of energy—far more than the entire human population uses at any given moment. It seems unlikely that any alien civilization would gather such an immense amount of energy simply to send a signal toward Earth.
4. A Gigantic Supervoid—One of the Largest Structures in the Universe
Space is filled with vast empty regions known as voids. Some of these voids are so enormous that they are classified as supervoids. A typical supervoid could encompass 10,000 galaxies, though they generally lack sufficient density to contain them.
One of these supervoids stands out as one of the largest known structures in the universe. Positioned three billion light-years away, this supervoid is so immense that even if an object were traveling at the speed of light, it would take hundreds of millions of years to cross it. To locate and study this supervoid, scientists needed to construct three-dimensional maps.
Intriguingly, scientists have found that this supervoid might also absorb energy from light passing through it. Moreover, as the universe continues to expand, the supervoid will grow larger.
3. The Undead Star
A supernova is a cataclysmic event that marks the end of a star's life when it depletes its fuel. This explosion often signifies the final chapter of a star's existence. However, recent discoveries have shown that this isn't always the case.
In 1954, astronomers witnessed the powerful explosion of the iPTF14hls star, located 500 million light-years away, which briefly became a brilliant supernova. Remarkably, in 2014, the same star exploded once again. Initially, astronomer Iair Arcavi speculated that the 2014 event might have been caused by a different star somehow arriving at the location of the original 1954 explosion.
To his astonishment, he realized that it was the same star. This led to iPTF14hls being dubbed the “zombie star” because it appeared to have risen from the dead. While iPTF14hls is the only star known to have exploded twice, scientists believe that multiple explosions are likely in stars with masses greater than 100 times that of the Sun.
Despite this, astronomers are convinced that iPTF14hls has perished for good this time. Still, they could be mistaken. Supernovae typically shine brightly for around three months before slowly fading to darkness, but iPTF14hls remained brilliant for over two years. We might need to wait several decades to see if it explodes again.
2. CMB Cold Spots
The universe is filled with remnants of energy from the big bang, known as cosmic microwave background radiation (CMB). This radiation permeates every corner of the universe, except for certain regions referred to as CMB cold spots. The origin and nature of these cold spots remain a mystery, and some scientists speculate that they could actually be supervoids, like those mentioned previously.
However, two astronomers from Durham University in England, Tom Shanks and Ruari Mackenzie, offer an alternative theory. They propose that CMB cold spots could represent the point where our universe collided with another, alternate universe. Their hypothesis arose after analyzing light emitted from thousands of galaxies in our universe.
Upon their investigation, Shanks and Mackenzie found that the CMB cold spots were surrounded by several small voids, rather than a single massive supervoid. These voids were, in turn, encircled by small galaxies. While they acknowledge that these voids could be explained through known physical phenomena, they suggest that another plausible explanation could be a collision between our universe and an alternate one.
1. Mysterious Radio Signals From The M82 Galaxy
In May 2009, astronomers from the UK detected unusual radio signals while observing an exploding star in the M82 galaxy. Typically, radio signals from space grow stronger over several weeks before gradually fading. However, the signals from M82 remained consistent, even though the source of the emission was moving at an extraordinary speed.
Some scientists suggest that the radio signals might have been emitted by a supermassive black hole located in the M82 galaxy. This theory is plausible, as many galaxies are known to contain supermassive black holes that release radio waves from their centers. However, the signals did not appear to originate from the core of the M82 galaxy.
Another possibility raised by scientists is that the signals were produced by a microquasar, a black hole that forms when a large star undergoes an explosion. Microquasars are smaller than the supermassive black holes found in galactic centers, but still possess masses between 10 to 20 times that of our Sun.
Some researchers argue that the mysterious radio waves, which lack X-rays, cannot be attributed to microquasars, as these typically emit both radio waves and X-rays. However, there are suggestions that the microquasar responsible could be situated in an unusual environment that prevents the X-ray emission.
