A new study suggests that planetary defense strategies should not ignore a strange and highly unstable type of object, nicknamed a "dark comet."
"Dark comets" is the nickname scientists have given to several recently discovered strange cosmic objects that exist half asteroid, half comet.
A study recently published in the scientific journal Icarus shows that "dark comets" are not only strange but also much more dangerous than we thought.
A hybrid object between a comet and an asteroid could be a terrifying killer for Earth - Photo AI: Anh Thu
A hybrid object between a comet and an asteroid could be a terrifying killer for Earth - Photo AI: Anh Thu
In general, comets are very different from asteroids.
Comets come from the outer reaches of the Solar System, have stable orbits, sometimes disturbed by the gravitational interactions with giant planets, and travel towards the Sun, where they are gradually disintegrated by the hot star. It is this process that creates the magical tail.
Asteroids, in contrast, typically reside in the "inner solar system" region, mostly between Mars and Jupiter.
They are much more solid than comets, so they can survive much longer near the Sun. They also sometimes end up in unstable orbits, approaching or even colliding with Earth.
The "dark comet", only recently identified, exhibits a strange third state.
These objects are small, with the largest measuring only a few tens of kilometers across. Unlike comets, they do not show visible outgassing or evaporation of volatile elements such as water.
They also don't follow perfect orbits. They show evidence of antigravity acceleration—which implies that there's some other force that's gently pushing their orbits—in an unusual way.
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All small objects in our star system, including asteroids, have some degree of non-gravitational acceleration, but astronomers can usually determine the cause.
Asteroids, for example, are heated unevenly by the Sun, causing small but measurable shifts in their orbits.
But the dark comet's antigravity acceleration is incompatible with uneven heating, suggesting that some other "force" is at work. An invisible, comet-like outgassing may be contributing.
The team of authors led by researcher Aster G. Taylor from the Michigan Institute for Computational Engineering and Discovery (USA) suspects that the dark comet likely originated in the asteroid belt between Mars and Jupiter, but was impacted by Saturn and became unstable.
Furthermore, it is a special type of asteroid that contains a large amount of light-reflecting molecules, such as water.
Their unstable orbits and uncertain combination of characteristics make them particularly dangerous near-Earth objects. They are small, fast, hard to detect, and their paths are difficult to predict.
Therefore, they can cause completely unexpected global attacks.
They may have struck: The properties of "dark comets" suggest that this family may have been the space objects that crashed into the early Earth, carrying the first water-rich molecules that gave our Earth water and thus life.
Regardless, they are dangerous for now. Scientists say it is important to further clarify the origin of these objects, and from there design more suitable plans to prevent surprise attacks.
