Hubble gets photobombed by an asteroid in beautiful image of a spiral galaxy

Astronomers have stumbled upon a cosmic treasure trove by using NASA’s Hubble Space Telescope in an unexpected way. They’ve discovered over a thousand photos of asteroids that had been hiding in Hubble images, unnoticed until now.

Lead researcher Pablo García Martín from the Autonomous University of Madrid delved into 19 years’ worth of Hubble images to find these elusive space rocks.

Working alongside co-author Bruno Merín of the European Space Astronomy Centre, they found 1,701 asteroid trails, with 1,031 of them being entirely new discoveries.

Galaxy UGC 12158 has a surprise guest

One of the standout images features the barred spiral galaxy UGC 12158, which got an unexpected visitor — a photobombing asteroid passing by during the telescope’s exposure.

Barred spiral galaxies like UGC 12158 are fascinating. They have swirling arms that extend from a central bar-shaped region.

These bars are more than just cosmic eye candy; they play a crucial role in channeling gas toward the galaxy’s center, fueling the birth of new stars.

These bar structures aren’t permanent fixtures. Astronomers believe they slowly disperse over time, and the galaxies eventually evolve into regular spirals. It’s like watching a cosmic dance that changes steps over millions of years.

Hubble’s hunt for hidden asteroids

But how did these asteroids go unnoticed for so long? The answer lies in the sheer volume of data.

Hubble has been snapping pictures of the universe for decades, amassing a vast archive that’s simply too massive for astronomers to sift through alone.

Enter the citizen scientists — over 11,000 volunteers from around the globe who teamed up with the researchers.

Their mission? To comb through nearly 20 years of images in search of asteroid trails.

“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,” García Martín remarked.

“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,” he added.

Why do we care about asteroids?

You might be wondering, why all the fuss about asteroids? These space rocks are like time capsules, holding clues about the early solar system.

The abundance of small asteroids supports the idea that they are fragments from larger bodies that collided and broke apart over billions of years.

It’s like piecing together a cosmic jigsaw puzzle, helping us understand how planets and other celestial bodies formed.

This finding challenges an alternative theory suggesting that these smaller fragments formed as such billions of years ago. Understanding which theory holds true can significantly impact our knowledge of solar system evolution.

Citizen science, asteroids, and Hubble

The Hubble Asteroid Hunter project, launched in 2019, was a true team effort.

Volunteers provided nearly 2 million identifications, which were then used to train a machine learning algorithm to find even more asteroids.

“Asteroid positions change with time, and therefore you cannot find them just by entering coordinates, because at different times, they might not be there,” explained Merín.

“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.”

This innovative approach may be effectively applied to other datasets in the future, showcasing the power of combining human effort with technology.

How Hubble finds asteroids

Hubble’s unique position orbiting Earth allows it to capture images of asteroids as they move. Unlike stars, which stay relatively fixed, asteroids can appear as streaks or trails in photographs.

From Earth-based telescopes, an asteroid leaves a straight streak across the picture. But in Hubble’s images, they appear as curved trails due to the telescope’s motion around Earth.

By analyzing these trails, scientists can determine how far away the asteroids are and estimate their orbits.

The faintest asteroids they found are incredibly dim — about one forty-millionth the brightness of the faintest star visible to the naked eye.

Snapshot of the universe

The image of UGC 12158 holds more than just an asteroid. It also contains a supernova — an exploding star — called SN 2004ef.

This bright blue point near the galaxy’s center was first spotted by two British amateur astronomers in September 2004.

At around 400 million light-years away, this supernova offers a glimpse into the life cycles of stars far beyond our own galaxy. It’s a reminder of the dynamic and ever-changing nature of the universe.

The team plans to study these newly discovered asteroids further, looking into their orbits and properties like rotation periods.

However, since many of these images were taken years ago, tracking the asteroids now isn’t possible. But the data still provides valuable insights that can be used to refine models of asteroid behavior and solar system evolution.

Why does any of this matter?

This discovery highlights how much can be achieved when professionals and the public join forces.

By tapping into the enthusiasm and curiosity of citizen scientists, the team was able to process an enormous amount of data that would have been overwhelming otherwise.

“This is important for providing insights into the evolutionary models of our solar system,” García Martín emphasized.

Understanding asteroids isn’t just an academic exercise. These objects can tell us about the building blocks of planets, including our own Earth.

They can also help us learn about potential hazards. After all, asteroids have impacted Earth before, and knowing more about them can help us prepare.

The full study was published in the journal Astronomy and Astrophysics.

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