NASA's Hubble Space Telescope embarks on a cosmic treasure hunt, scanning the vast expanse to capture the trails of small asteroids that dart through space.

Unlike planets, these celestial wanderers evade easy detection, demanding a keen eye and advanced technology to reveal their presence.

Hubble Looks for Small Belt Asteroids

Astronomers recently went on a mission to uncover a hidden population of diminutive asteroids using an extensive archive of images captured by the Hubble Space Telescope. 

Their quest involved sifting through a staggering 37,000 images spanning nearly two decades, meticulously analyzing each frame for the faint traces of asteroids. 

Their efforts yielded a remarkable discovery: 1,701 asteroid trails, over a thousand of which previously eluded detection. Among these newfound asteroids, approximately 400 are diminutive, measuring less than one kilometer in diameter.

Assisting in this astronomical endeavor were volunteers from across the globe, known as "citizen scientists," who dedicated their time and expertise to the identification process. 

Their contributions and sophisticated machine-learning algorithms proved instrumental in identifying these elusive celestial travelers. 

"We are getting deeper into seeing the smaller population of main belt asteroids. We were surprised with seeing such a large number of candidate objects," said lead author Pablo García Martín of the Autonomous University of Madrid, Spain. 

"There was some hint of this population existing, but now we are confirming it with a random asteroid population sample obtained using the whole Hubble archive. This is important for providing insights into the evolutionary models of our solar system."

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Like Shattered Pottery in Space

NASA says the abundance of small asteroids unearthed by this survey provides crucial clues to their origins and evolution.

One prevailing theory suggests that these small cosmic fragments are remnants of larger asteroids that have undergone cataclysmic collisions akin to shattered pottery. 

According to NASA, an alternative perspective posits that these tiny fragments originated billions of years ago, defying conventional wisdom by resisting aggregation into larger bodies. 

Yet, the absence of a viable mechanism to prevent their growth challenges this notion, prompting astronomers to scrutinize existing models and refine their understanding of asteroid formation and dynamics.

Scientists spotted asteroids using Hubble's position as it circles Earth. Moving across its view, these asteroids leave streaks, like signatures in the sky, that help understand where they're going and what they're like.

Most of the asteroids caught hang out in the main belt between Mars and Jupiter. Hubble's cameras measure their brightness, and by comparing this to their distance, scientists estimate their size. NASA adds that the dimmest asteroids seen are about one forty-millionth as bright as the faintest star visible to the naked eye.

"Asteroid positions change with time, and therefore you cannot find them just by entering coordinates, because at different times, they might not be there,"  said co-author Bruno Merín of the European Space Astronomy Centre in Madrid, Spain.

"As astronomers we don't have time to go looking through all the asteroid images. So we got the idea to collaborate with over 10,000 citizen-science volunteers to peruse the huge Hubble archives." 

The findings of the team were published in the journal Astronomy and Astrophysics.

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