Last October, Oumuamua, the first known interstellar visitor to our solar system, swept past Earth. In its home star system, it would be one of the trillions of asteroids - rocky debris left over from its formation. So what makes Oumuamua so important to us? And why study asteroids at all?
Today, the asteroids of our solar system are concentrated between Mars and Jupiter in a dense region known as the asteroid belt. It is believed that they are all remnants of the cloud of gas and dust from which the planets, sun and moon were formed. Asteroids vary in size; some of them are so large that their gravitational pull is enough to attract their own satellite.
When the path of the asteroid around the Sun intersects with the Earth, they collide. In the early days of the solar system, before the Earth was ready for life, our world was severely affected by such a blow. But as the asteroids attacked our primitive home one by one, they also sowed life on it.
“The asteroids that bombarded the Earth in the early days of the solar system are believed to have contributed significantly to the carbon-rich and water-rich material present on Earth's surface today,” says NASA astronaut Joseph Masero. However, he stressed that this issue is still being investigated.
One theory, called panspermia, suggests that asteroids hitting Earth four billion years ago brought the seeds of life from other planets to our planet.
When Oumuamua reached our solar system, astronomers for the first time had the opportunity to study how planets in other systems are formed. By examining the shape of the stone and the specific wavelengths of light that it reflected, astronomers determined its composition.
Its color and spectrum were in the order of things, but astronomers were surprised by the absence of erupting gas and dust, like most comets, when Oumuamua flew past the Sun. A recent study suggests that the object is covered in a layer of organic compounds that insulates its icy interior from solar heat.
Masero notes that asteroids can help answer the question of how unique we are, and how unique life itself is. Other solar systems may be comparable to ours or be completely different. This is what astronomers are still trying to figure out. Such distant asteroids may contain information about the formation of planets, and maybe even life outside our solar system.
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