On December 25, 2024, you were not alerted by the news that an asteroid two-thirds the size of a football field was passing close to the Earth. Yet it was. Just 2.1 lunar distances away, a 50-meter-wide rock barreled past our planet at a staggering 38,000 miles per hour.
Why was there no breaking news on CNN? Or iPhone alerts saying a city-busting asteroid was coming closer to us than any that big in decades?
Because we have a blind spot.
There are hundreds of telescopes around the world that either actively watch for asteroids, or respond immediately and track objects if alerted. We don't miss much out there.
But telescopes rely on reflected sunlight to spot asteroids. If an asteroid happens to be approaching on what astronomers call "the day side" -- right between the Earth and the Sun -- it can be lost in the brightness. Like trying to see a flashlight in front of a floodlight.
This is rare, but it's scary. Because an asteroid coming from the sunward side is, by definition, on a trajectory straight toward Earth. So it's these most dangerous objects we're most likely to miss -- where our usual networks of telescopes fail to give us advanced warning. These massive rocks only become visible after they've passed us. Which is exactly what happened with Asteroid 2024 YR4 last December. It was only detected two days after its closest approach.
In the movies, the heroes have weeks after detecting Earth-destroying asteroids to figure out how to stop them. They have time to assemble a rag tag crew of outcasts to drill into the rock and plant a nuclear weapon. (If that's the preferred solution.)
In real life, it's possible we get no warning at all.
Like the morning of February 15, 2013, when people in the Russian city of Chelyabinsk looked up to see a blinding fireball streak across the sky. There was no warning. The blazing comet was just there, in the blue sky where it didn't belong.
Seconds later, the one million people living in the city heard a massive sonic boom. Shockwaves slammed the buildings. Windows shattered everywhere. Witnesses described the sky turning dark from the thick trail of smoke and dust trailing the projectile from space. People thought they were attacked. The energy released was over 500 kilotons -- 30 times the Hiroshima bomb. It wasn't until scientists examined the impact crater that they realized what happened. The city was hit with a 65 foot wide meteor that weighed 13,000 metric tons at over 40,000 miles an hour.
It's lucky Asteroid 2024 YR4 didn't make similar contact. It's more than twice the size of the Chelyabinsk meteor.
But last December's Asteroid is still on an Earth-crossing orbit, in an elliptical path known as an Apollo-type orbit. What does this mean? Simply put, it's coming back.
In 2032 the asteroid will once again barrel past the Earth. Knowing this, International Planetary Defense officials studied the asteroid's trajectory. By March of this year they'd done enough calculations to rule out an Earth impact.
At the same time, the European Space Agency is doing something about that blind spot. They are launching the Near-Earth Object Mission in the InfraRed (NEOMIR) satellite. NEOMIR will be equipped with an infrared telescope and positioned at a special spot in space called the Sun-Earth Lagrange Point, where gravity and motion balance perfectly, allowing the satellite to "hover" between the Earth and the Sun. Because it uses infrared, it won't be blinded by the light -- we'll finally be able to see danger coming.
NEOMIR would have detected asteroid 2024 YR4 a month earlier than our ground-based telescopes did. Plenty of time for that rag tag crew of minors to fly out there and plant a bomb in the asteroid. Or come up with an easier way to knock it off course.
So we're all good.
Except all those calculations on Asteroid 2024 YR4's path revealed a new, disturbing possibility. It may hit the moon.
A massive rock hitting the moon at 38,000 mph could send significant debris into the Earth. Fireballs might rain down causing untold damage.
2032 may be an exciting year yet. Hopefully we'll see it coming.