- 7 weeks ago
Asteroids that almost hit Earth have long fascinated scientists, space agencies, and the general public because they reveal how active and dynamic our solar system truly is. These near-miss events are not just dramatic stories about space rocks passing by our planet; they are also important reminders of the need for asteroid monitoring, planetary defense, and ongoing astronomical research. When a large asteroid passes close to Earth, it highlights both the vulnerability of our planet and the remarkable progress humanity has made in detecting objects near our orbit. In many cases, the miss distance may sound enormous in everyday terms, but in astronomical terms it can be alarmingly close.
Category
🛠️
LifestyleTranscript
00:00Space is basically shooting rocks at us all the time. Most burn up, most miss by millions of
00:05miles, and we never even notice. But a handful of times, something has come close enough that
00:10scientists at NASA and the European Space Agency stopped what they were doing and watched the sky.
00:16Some of these rocks were spotted years in advance, some were spotted hours before they showed up.
00:21And one of them is still coming, set to buzz past us in 2029 closer than some of our own
00:26satellites.
00:27So let's go through eight times, an asteroid got close enough to make headlines,
00:32starting with the one that kicked off the modern era of asteroid panic.
00:36In March of 1998, astronomers dropped a bomb on the public. A mile-wide asteroid called 1997 XF11
00:43had been tracked since the previous December, and new orbit calculations suggested it could
00:49come frighteningly close to Earth in the year 2028. The Minor Planet Center in Cambridge,
00:54Massachusetts sent out a message meant for a small circle of asteroid trackers,
00:58and it leaked straight into the news cycle. The message said new observational data on the
01:03recently discovered asteroid 1997 XF11 suggested there was a chance that the half-mile-wide object
01:10could hit Earth in 2028. NPR ran a segment saying a mile-wide asteroid called 1997 XF11 appeared to be
01:18heading for a close encounter with Earth in the year 2028. And astronomers said they couldn't yet
01:24rule out the possibility that it would strike the Earth. That's the kind of line that gets
01:28everyone's attention. Scientist Brian Marston of the International Astronomical Union tried to calm
01:34things down, saying chances were it would miss Earth, while still admitting the possibility of
01:39collision wasn't entirely off the table. People started running numbers on what a hit would
01:44actually look like. One researcher estimated that an asteroid the size of 1997 XF11 colliding with
01:51Earth at more than 17,000 miles an hour would explode with an energy of about 320,000 megatons
01:59of dynamite, almost 2 million Hiroshima-sized atomic bombs. If it landed in the ocean, the same report
02:05warned of a wave hundreds of feet high slamming into coastlines for thousands of miles. If it hit land,
02:11picture a crater 20 miles wide in a sky choked with dust for months. Then within a day, everything
02:17changed. Astronomers dug up old photographic plates taken years earlier that happened to capture the
02:23asteroid without anyone realizing it at the time. Those images let scientists nail down its orbit with
02:29far more precision, and the numbers moved fast. The revised prediction pushed the 2028-close approach out
02:36to an unremarkable 980,000 kilometers. A team at NASA's Jet Propulsion Laboratory later explained the
02:43object would make what was, at the time, easily the closest ever predicted approach of a minor planet
02:48to Earth, with a missed distance calculated at less than one quarter of a lunar distance.
02:53That's how close the first estimate really was, inside a quarter of the distance to the moon.
02:58The whole episode became a lesson for how these announcements should be handled.
03:02Years later, JPL scientist Paul Chodes pointed to the event as proof of the need for clarity and
03:08precision in communicating with the public about close passes of near-Earth objects, and the
03:13importance of peer review before public statements are made. XF-11 never came close to hitting us,
03:20but it put asteroid impact into the public vocabulary in a way that hadn't happened before, and it forced
03:25the entire tracking community to get more careful, and faster, about how they double-check in orbit
03:31before anyone picks up a phone. Ten years after the XF-11 panic, something different happened.
03:37This time, instead of a false alarm about a future decade, astronomers spotted a small asteroid,
03:43and for the first time in history, correctly predicted it would hit Earth's atmosphere,
03:47before it actually happened. The object was designated 2008 TC3. It was found by astronomer Richard
03:54Kowalski at the Catalina Sky Survey in Arizona, just hours before it slammed into the atmosphere
04:00over Sudan's Nubian desert. Unlike every close call before it, this wasn't a near-miss that stayed in
04:06space, this rock actually came in. It was tiny, only a few meters across, so there was never a threat
04:12to
04:12anyone on the ground. It burned up spectacularly, and fragments rained down as meteorites that scientists
04:18later collected from the desert floor. A batch that came to be known as the Almohada Citta meteorites.
04:24What made this one historic wasn't its size. It was the speed of detection and the accuracy of the
04:30prediction. For the first time, the world's asteroid trackers had gone from, we see something,
04:35to here's exactly where and when it's going to hit, in less than a day. It proved the detection network
04:40wasn't just theoretical. It could actually work under real pressure, on short notice, with a real object
04:46barreling toward the planet. That capability would matter a lot for everything that came after it,
04:51because most dangerous-sized objects don't announce themselves years in advance. They show up fast,
04:57and the only defense is a system quick enough to catch them. Fast forward to February 2013,
05:02and astronomers were tracking something on a much bigger scale than a car-sized rock. Asteroid 2012
05:08DA14 had been discovered a year earlier at the La Sagra Observatory in Spain, and its return trip past Earth
05:15was going to be one for the record books. On its closest approach, near-Earth asteroid 2012
05:21DA14 passed at a distance of 27,700 kilometers from Earth's surface, inside the geosynchronous
05:28satellite ring. That's the shell of space where weather satellites, GPS satellites, and communications
05:34satellites live. This rock cut straight through it. Scientists at the Planetary Society put it plainly,
05:39saying that at roughly 45 meters across, this was the largest asteroid that had come so close
05:45since humans had been making great efforts to track such things. NASA's near-Earth object office
05:50confirmed there was zero chance of impact, but stressed how rare the geometry was. Their statement
05:56described it as passing so close that it would pass inside the ring of geosynchronous weather and
06:02communications satellites, giving researchers a rare shot at studying an object this size up close,
06:07using ground telescopes and radar. What made DA14 extra interesting is that its orbit around the
06:13Sun was almost a mirror of Earth's own, at a period of roughly 366 days, which is why it kept
06:20swinging
06:20back for repeat visits every year. Astronomers also caught something with the timing. After the
06:25closest pass, the asteroid was expected to slip briefly into Earth's shadow, vanishing from view for
06:31about 18 minutes before reappearing. It was a science bonanza with genuinely zero danger. But nobody in
06:37the tracking community was fully relaxed that day. Because a few hours before DA14 even arrived,
06:43something else showed up completely unannounced. On the very same day astronomers worldwide had their
06:49eyes locked on 2012 DA14, an unrelated object came in from a completely different direction and actually hit.
06:56Over the Russian city of Chelyabinsk, a rock roughly 20 meters across tore through the sky and exploded in
07:02the atmosphere, and nobody saw it coming until it was already a fireball. The United Nations later
07:07described it as an extraordinarily large fireball, the most energetic impact event recognized since the
07:131908 Tunguska blast in Russian Siberia. The Wikipedia record of that year's close approaches notes that of
07:20the near-earth objects detected in 2013, five carried more energy than a one-kiloton blast, including the
07:26440-kiloton Chelyabinsk meteor, estimated at 20 meters in diameter, which injured around 1,500 people
07:34and damaged over 7,000 buildings. The shockwave blew out windows across the city, sent people to
07:40hospitals with cuts from shattered glass, and turned into one of the most watched natural events of the
07:45decade because so many Russian drivers had dashcams running that morning. And the timing right alongside
07:51DA14 wasn't lost on anyone. Two completely unconnected space rocks, one tracked for a year,
07:58one invisible until it detonated, arrived on Earth's doorstep within hours of each other.
08:03It was the clearest demonstration, yet that the ones we track aren't necessarily the ones we need to
08:09worry about. The dangerous ones can be the ones nobody spots at all until they're already glowing in the
08:14sky. Six years later, almost the exact same nightmare played out again, an object nobody caught in time,
08:21except this one didn't hit. It just came close enough to make scientists visibly rattled.
08:26Asteroid 2019 OK was spotted by astronomy teams in Brazil and the United States only days before its
08:33closest approach. NASA's own Center for Near-Earth Object Studies later called it the largest asteroid to
08:39pass this close to Earth in a century, reporting that it approached Earth at about 40,400 miles above
08:45the surface, one-fifth the distance to the moon. And while other known asteroids had passed closer,
08:51none had been as large, with 2019 OK estimated at 195 to 425 feet in size. Astronomers who studied the
08:59object didn't hold back on how they described it. Alan Duffy at Swinburne University told reporters it
09:05would have hit with over 30 times the energy of the atomic blast at Hiroshima and called it a
09:11city-killer asteroid outright. Michael Brown at Monash University admitted it was impressively close,
09:17that it hadn't quite sunk in yet, and that it was a pretty big deal. What really rattled people was
09:22how
09:22it got past detection in the first place. NASA's own internal emails, later obtained through a Freedom
09:28of Information Act request, showed that the agency's planetary defense officer, Lindley Johnson,
09:34only learned about the object roughly 30 minutes before it passed, warning colleagues that a 57
09:39to 130-meter-sized asteroid would pass Earth at only 0.19 lunar distances, and that it had been
09:46spotted about 24 hours prior. CNEOS later explained the reason it slipped through. The asteroid's highly
09:53elliptical orbit meant it barely moved against the star field until the final days. So ground telescopes
09:59had trouble flagging it as anything unusual, until it was almost on top of us. Just over a year after
10:052019 OK, an even closer visitor showed up, and this one blue-right passed the previous record.
10:11In August of 2020, an asteroid roughly the size of a small car skimmed over the Indian Ocean,
10:17at a distance of only around 1,830 miles above the surface. That's closer to Earth than some satellites in
10:24low orbit, and at the time it stood as the nearest known asteroid flyby ever recorded,
10:29that didn't actually make contact with the atmosphere. Astronomers didn't spot it coming.
10:34Like 2019 OK a year before, this asteroid was only picked up by the Zwicky Transient Facility Survey in
10:40California, after it had already made its closest pass and was heading back out into space.
10:45Its size somewhere in the range of a few meters, meant it wouldn't have caused catastrophic damage,
10:50even in a direct hit, likely breaking up in the atmosphere the way small rocks usually do.
10:55But the distance was the headline. It came in low enough that, had its path been just slightly
11:00different, it would have been grazing the edge of the atmosphere itself. What this flyby really
11:05underlined was a pattern the tracking community kept running into again and again. The bigger asteroids,
11:11the ones that could genuinely level a city, are usually caught years or months out because they're
11:16bright enough and their orbits are stable enough to nail down early. But the small ones, the ones
11:21the size of a delivery truck or a compact car, keep sneaking in from angles telescopes struggle to
11:26cover, especially anything approaching from the direction of the sun. Every time one of these small,
11:32fast, practically invisible objects skims past, it resets what counts as the closest ever. And it was
11:38only a matter of months before the record got broken again. In January of 2023, that record fell hard.
11:45An asteroid about the size of a box truck, designated 2023 BU, was discovered by an
11:51amateur astronomer in Crimea, named Gennady Borisov, the same person credited with finding
11:56the first confirmed interstellar comet. Within days, NASA's scout system flagged something
12:02extraordinary about its path. NASA's Jet Propulsion Laboratory stated flatly that the object was predicted
12:08to make one of the closest approaches by a near-Earth object ever recorded, and that it would zoom over
12:14the southern tip of South America, only 2,200 miles above the planet's surface, well within the orbit
12:20of geosynchronous satellites. David Farnakia, the JPL engineer who built the scout system, put it in
12:27blunt terms, saying scout quickly ruled out 2023 BU as an impactor. But despite the very few observations,
12:34it was nonetheless able to predict that the asteroid would make an extraordinarily close approach with
12:40Earth. In fact, one of the closest approaches by a known near-Earth object ever recorded. CNN's coverage
12:46laid out just how tight that margin was, reporting the asteroid zipped over the southern tip of South
12:51America, about 2,200 miles above Earth's surface, well within the orbit of global satellites. NPR added a
12:59way to visualize it, noting the distance was a little shorter than a straight-line trip from New York City
13:04to Las Vegas. The close pass didn't just rattle nerves, it physically altered the asteroid's path.
13:10CNN noted that Earth's gravity changes the trajectory of asteroids, but 2023 BU came so close that its
13:17orbit around the Sun changed after the encounter, having previously taken about 359 days to circle the Sun.
13:25A rock that had been quietly looping the Sun on an almost Earth-like schedule got yanked onto a completely
13:30new
13:30path, just from swinging that close to us one time. Every close call so far has been something that
13:36already happened. This last one hasn't, and it's the biggest of them all. Its name is Apophis, and it's
13:42set to make history in a matter of years, not decades. Apophis was first spotted in 2004 at Kitt Peak
13:49National Observatory, and almost immediately, it became one of the most feared objects ever catalogued.
13:55The European Space Agency explained that when Apophis was discovered, the initial observations
14:00indicated a small chance it could impact Earth in 2029, 2036 or 2068, and a collision would have been
14:08devastating enough that the asteroid was named after the Egyptian god of chaos and destruction.
14:14The risk numbers got serious fast. ESA notes the object was soon identified as one of the most
14:20potentially hazardous asteroids ever detected, with the risk of an impact in 2029 rising as high as
14:272.7%, and Apophis achieving the highest ever rating on the Torino scale. That risk has since been ruled
14:34out. But what's left behind is still remarkable, a guaranteed close pass unlike anything humans have
14:40tracked in advance before. ESA states plainly that on April 13, 2029, Apophis will briefly come within
14:4832,000 kilometers of Earth's surface. The closest approach of an asteroid of this size that humans
14:54have ever been aware of in advance. This is a genuinely massive object, roughly 340 meters across.
15:01According to the UN's own briefing on the flyby, big enough that if the earlier collision odds had held
15:06up, we wouldn't be talking about broken windows in one city, we'd be talking about something regional,
15:12maybe worse. Because it's guaranteed and it's close, scientists are treating the 2029 flyby less like
15:18a threat and more like a once-in-a-generation opportunity. Multiple space agencies are planning
15:24to have telescopes and spacecraft trained on it as it passes, because Earth's gravity is expected to
15:30physically reshape the object. ESA describes how during the approach, Apophis will be affected by
15:36Earth's mighty gravity. With the side nearest Earth pulled more strongly than the far side,
15:41creating tidal forces that could stretch and squeeze it, potentially triggering quakes and landslides,
15:46and changing the way it rotates. The flyby is even expected to permanently change the shape of its orbit
15:52around the sun. So that's where the story of Apophis stands right now, not a disaster, but a countdown.
15:58A 400-yard-wide asteroid, dipping inside the ring of our own satellites. In full view,
16:04years after we first thought it might be the one that finally got us. Out of everything on this list,
16:09the ones from the past are settled. This is the one still on the calendar, and when the date arrives,
16:14it'll be the closest look anyone alive has ever gotten at a rock that big passing that near to home.