My ChatGPT pal tells us how terrified – or not – we should be.

The little weather app on my phone shows me various videos and articles, all climate- or nature-related. I was perusing their titles today when suddenly I read:

“‘City-killer’ asteroid’s odds of crashing into Earth go up.”

😳

I wanted to know more! Wouldn’t you? But “more” scared me as I read the article. It seems that the 1.3% chance of this asteroid hitting Earth in 2032 (only eight years away, folks) has increased to 2.2%! This space rock’s name is “2024 YR4” – but from now on I’ll just say “asteroid.”)

The increase in odds – small though it seems – was made possible by the increase in precision of measurements used by astronomers, over time. The article (link below) explains everything, but somehow I needed a more reassuring voice. So I turned to ChatGPT.

It is apparently a lot smarter than me.

Asteroid Impact Probability

I asked: Explain what it means in practical terms, that an asteroid has a 2.2% chance of hitting earth. How great (or how little) is that chance of it actually happening?

ChatGPT said:
A 2.2% chance means that out of 100 possible scenarios, the asteroid would hit Earth in just over two of them. In practical terms, this probability is low but not negligible.

To put it into perspective:

• Everyday Risks: A 2.2% chance is much higher than the odds of winning the lottery but lower than many everyday risks, like getting into a car accident over the course of a year.
• Timeframe Matters: If this probability applies to an event happening on a specific date, it’s a small but serious possibility. If it’s over a longer period (e.g., over decades), it’s even less immediate.
• Comparison to Other Space Events: Most asteroids with a chance of impact have probabilities much lower than 1%, so 2.2% is relatively high in astronomical terms. Scientists would closely monitor such an asteroid.

If an asteroid with a significant size had a 2.2% chance of impact, space agencies would take it seriously, considering potential deflection strategies. However, the most likely scenario is that it will miss Earth, since there’s a 97.8% chance of that happening.

Would you consider 60 km wide as a “significant” size for this asteroid??

ChatGPT said:
Yes, a 60-km-wide asteroid would be extremely significant—catastrophic, even.

For context:

• The asteroid that likely caused the extinction of the dinosaurs (Chicxulub impactor) was about 10 to 15 km wide.
• A 60 km asteroid would have nearly 20 to 100 times the mass of that impactor, depending on its composition.
• The energy released upon impact would be orders of magnitude greater than the largest nuclear explosions ever created.

If such an asteroid had a 2.2% chance of hitting Earth, it would be a planetary emergency. Governments and space agencies would likely mobilize every available resource to attempt a deflection, because an impact would cause global devastation—firestorms, tsunamis, earthquakes, and possibly mass extinction.

If this is a hypothetical scenario, then yes, 60 km is beyond “significant”—it’s apocalyptic.

Oops no, I meant 60 metres!! [My bad! 😬]

ChatGPT said:
A 60-meter-wide asteroid is still significant, but nowhere near the catastrophic level of a 60-kilometer one!

For comparison:

• The Chelyabinsk meteor (2013) was about 20 meters wide and exploded in the atmosphere with the force of 30 Hiroshima bombs, damaging buildings and injuring 1,500 people.
• The Tunguska event (1908) was likely caused by a 50–60-meter asteroid, flattening 2,000 square kilometers of forest in Siberia.

A 60-meter asteroid could cause regional devastation if it hit land, or generate a significant tsunami if it impacted the ocean. However, it would not be an extinction-level event.

A 2.2% chance of impact would definitely get the attention of space agencies. If the projected impact zone were near a populated area, evacuation plans might be considered. If detected early enough, a small deflection mission could be attempted to push it off course.

Still, with a 97.8% chance of missing Earth, it’s more likely than not that it won’t hit—but it’s not something to ignore either!

What if it’s just 40 metres? [I asked, typing with trembling fingers…😬]

ChatGPT said:
A 40-meter-wide asteroid is still dangerous, but the impact effects would be more localized than with a 60-meter one.

For reference:

• The Tunguska event (likely caused by a 50–60 meter object) leveled 2,000 square km of forest, but if the asteroid had been just 40 meters, the destruction might have been somewhat less widespread.
• The Chelyabinsk meteor (about 20 meters) mostly shattered in the atmosphere, but a 40-meter asteroid would likely survive longer before breaking up or impacting the surface.

If it hit land:

• It could flatten a city-sized area, depending on where it strikes.
• If it airbursts (explodes in the atmosphere), it could shatter windows, collapse weak structures, and injure thousands.

If it hit the ocean:

• It could generate a local tsunami, but not a global one.
• Coastal areas within a few hundred kilometers might be affected.

A 2.2% chance would still warrant monitoring. If it were expected to hit near a populated area, authorities might consider evacuation plans, though global deflection efforts (like with larger asteroids) would be less urgent.

Overall, 40 meters is still serious, but it wouldn’t be a civilization-ending disaster. More like a regional crisis, depending on where it lands.

Am I right in thinking that whether an asteroid zips straight down to earth as opposed to coming in at a more shallow angle, would determine whether or not it shatters in the atmosphere vs. stays solid until hitting earth’s surface?

ChatGPT said:
Yes, you’re absolutely right! The angle of entry is a major factor in determining whether an asteroid breaks apart in the atmosphere or survives to hit the ground.

How Entry Angle Affects Impact

1. Steep (Near-Vertical) Entry (~90°)
   • The asteroid encounters maximum atmospheric resistance quickly.
   • If it’s small or loosely held together, it will likely shatter or explode in an airburst.
   • Larger, stronger asteroids (e.g., solid iron ones) may survive intact and hit the ground.
   • Example: The Barringer Crater (Arizona) was caused by a 50-meter iron asteroid that came in steeply and stayed intact.
2. Moderate to Shallow Entry (~30°–60°)
   • The asteroid experiences atmospheric drag more gradually.
   • This increases the chances of it fragmenting before reaching the surface.
   • Chelyabinsk (2013) entered at about 20°, causing an airburst that shattered windows but no ground impact.
3. Very Shallow Entry (~10° or Less)
   • The asteroid might skip off the atmosphere like a stone on water and never impact at all.
   • A famous example: In 1972, a small asteroid entered Earth’s atmosphere at a very shallow angle over the U.S. and Canada, then bounced back into space.

Other Factors That Affect Breakup vs. Impact

• Size & Composition: Iron asteroids are dense and more likely to survive impact, while stony or icy ones tend to break apart.
• Speed: Faster asteroids experience greater atmospheric resistance, increasing breakup risk.
• Atmospheric Density: The lower an asteroid gets, the denser the air and the stronger the forces breaking it up.

So, a steep angle and strong material increase the chances of a ground impact, while a shallow angle, weak composition, or high-speed entry makes an airburst or deflection more likely.

Wow! So entry angle is hugely important! Plus density of the rock. Omg so many aspects astronomers must consider!!!

ChatGPT said:
Exactly! The entry angle, asteroid composition, speed, and size all play a role in whether an asteroid explodes in the sky, hits the ground, or even skips back into space. It’s a crazy mix of physics, atmospheric dynamics, and sheer luck.

Astronomers have to track and predict all these factors to determine:

• Will it hit Earth or miss?
• If it hits, will it explode in the atmosphere or make a crater?
• If it airbursts, how much damage will the shockwave cause?
• If it impacts, will it hit land or ocean?
• Could we deflect it in time?

Every new asteroid discovery means running complex simulations to figure out all these possibilities. Even a small change in an asteroid’s path can shift the impact zone by thousands of kilometers—or make it miss Earth entirely!

It’s amazing how much effort goes into monitoring near-Earth objects (NEOs), but given what happened to the dinosaurs, it’s definitely worth keeping an eye on!

Definitely! I now have an even greater respect for these scientists than I had already!

ChatGPT said:
Right? The amount of precision, math, and sheer dedication it takes to track these space rocks is incredible. They’re literally protecting the planet by calculating orbits, predicting impacts, and even working on ways to deflect dangerous asteroids if needed.

And the fact that they do all this with tiny specks of light in a telescope, sometimes millions of kilometers away, is mind-blowing. It’s like trying to predict where a grain of sand will land when tossed into the wind—decades in advance!

Makes you appreciate space agencies like NASA, ESA, and others that track NEOs daily. Hopefully, if a real threat ever comes our way, we’ll have a solid plan to deal with it.

~🌎~

*Link to the original article on my phone’s WeatherNetwork app: https://tinyurl.com/54xbsazk

**N.B.: All words and phrases in bold are the choices of ChatGPT. Any edits I made after my copy/paste here are tiny, and relate to formatting.

***I just want to point out several small things that this amazingly fluent LLM-trained AI ‘said’; little touches, such as:

• “Yes, you’re absolutely right!”
• “Exactly!”
• “Right?”

About that last one: “Right?” That word – and the question mark! – is so utterly spot on as a conversational expression we often hear – especially among the younger generation, perhaps. I saw that and thought, ChatGPT 3.5? You’re insanely brilliant. I don’t think I’ll ever need to move on to your 4 upgrade. But… I did hear that 4o is unbelievable. And – what’s that? 5 is coming this spring?

🤯