We Asked a NASA Scientist: What Are the Trojan Asteroids? [Video]

NASA’s Lucy mission, which launched on October 16, 2021, for the first reconnaissance of the Trojans, a population of primitive asteroids orbiting in tandem with Jupiter. In this artist’s concept (not to scale), the Lucy spacecraft is flying by Eurybates, one of the six diverse and scientifically important Trojans to be studied.
Credit: Southwest Research Institute

What are the Trojan asteroids? These mysterious space rocks have been gravitationally trapped in Jupiter’s orbit around the Sun for billions of years and hold clues to the formation of our solar system. NASA’s Lucy mission will be the first spacecraft to study these ancient relics up close. Lucy scientist Audrey Martin at Northern Arizona University has the details.

What are the Trojan asteroids? Let’s begin by going back over four billion years when the newly formed solar system consisted of trillions of tiny little rocky and icy objects. Many of these objects came together to form the planets. The majority of the others were scattered into the distant reaches of our solar system and beyond, but not all of them.

Some of these leftover space rocks are pristine asteroids that now orbit with Jupiter in two huge swarms leading and trailing the planet. They’re known as the Trojan asteroids. They’re really mysterious and we think that they come from the outer solar system. They’re also special in terms of understanding the evolution of the solar system because they’ve remained gravitationally stable for over billions of years. Astronomers have only been able to study these distant and enigmatic small bodies from Earth, but all of that is about to change.

NASA’s Lucy mission recently launched on a 12-year journey to visit these primitive asteroids. This will be the first time that we are able to see these objects up close!

So, what are the Trojan asteroids? They’re asteroids that orbit with Jupiter around the Sun that ultimately hold the clues to the formation of our solar system.

We Asked a NASA Expert Video Series

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• Is NASA Really Crashing a Spacecraft Into an Asteroid?
• Is NASA Aware of Any Earth-Threatening Asteroids?
• When Was the Last Time an Asteroid Hit Earth?
• How Did Perseverance Mars Rover Pick Its Landing Spot?
• What if an Asteroid Was Going To Hit Earth?
• Did Mars Ever Look Like Earth?
• What Are Lagrange Points?
• What Are the Trojan Asteroids?
• Is There Oxygen on Mars?
• Does NASA Know About All the Asteroids?
• Do Aliens Exist?
• Is There Weather on Mars?
• Will an Asteroid Ever Hit Earth?
• Is Mars Habitable?
• Could Microbes Survive a Trip to Mars?