Science In Action – "Asteroid 2024 YR4 Crisis Averted?"

BBC World Service | Host: Roland Pease | Date: February 27, 2025

Overview

This episode of Science in Action dives into some of the week’s most compelling science news stories, with a timely focus on the near-Earth asteroid 2024 YR4 and how scientists verified that it’s no longer a threat to our planet. The episode also delves into looming threats to the dark skies above one of the world’s premier observatories in Chile, cutting-edge climate science on Atlantic currents, and a remarkable breakthrough in wearable computing.

Main Segments & Key Insights

1. Asteroid 2024 YR4: How a Crisis Was Averted

[02:44–09:23]

Key Points:

• Just weeks ago, asteroid 2024 YR4 appeared to have a 1 in 50 chance of striking Earth in 2032.
• Continued high-precision observations, especially from Chile’s Very Large Telescope (VLT), refined the asteroid’s projected orbit, effectively ruling out the possibility of impact.
• Roland Pease interviews Olivier Heino of the European Southern Observatory (ESO) for a first-hand account of how astronomers track such threats.

Memorable Quotes:

• “Now the chance is essentially 0.001% is the number they're quoting.” – Roland Pease [02:44]
• “When you discover this kind of object, you know the orbit over one day, two days...the uncertainty is really large, like a huge beam covering a part of the sky. And the Earth happens to be in that beam.” – Olivier Heino [03:46]
• “Right now, we know the orbit well enough to know that we'll not be in trouble in 2032.” – Olivier Heino [07:42]

Interesting Moment:

• As more data rolled in and the uncertainty in YR4’s orbit shrank, the “beam” of possible Earth-crossing trajectories moved away from our planet, allaying fears of a future impact.
• The asteroid is now more likely to pass near the Moon, with Heino remarking: “The probability of impact for the Moon is getting higher and higher. But that's okay. It would be, would be entertaining.” [08:12]

Technical Insight:

• The challenge astronomers face as asteroids get fainter and tracking requires “stacking” dozens of images, similar to how sports photographers pan to keep a moving subject in focus. [05:53]

2. Threats to Chile’s Pristine Dark Skies

[09:24–21:43]

Key Points:

• Plans for a large green hydrogen factory near the VLT could threaten one of Earth’s last untouched dark-sky sites due to increased light pollution.
• Astronomers, including exoplanet hunter Julius Seidel, warn that even a modest increase in local brightness could cripple advanced observations and planetary defense efforts.

Memorable Quotes:

• “All of this will basically make observing in many many instances completely pointless.” – Julius Seidel [02:12, 15:35]
• “There's no such thing as a little bit of light pollution for astronomy from a facility this big, this close, or friendly light pollution from your neighbors.” – Julius Seidel [18:49]
• “For a cutting edge telescope, the impact is very significant. And it will basically destroy one of the last true dark sky sights in the world.” – Julius Seidel [15:52]

Notable Moment:

• Seidel describes the beauty and sensitivity of the Atacama as an astronomical site: “When you're in the Atacama, if you give your eyes the necessary 10 minutes to adjust...you can actually walk around and see trees and see buildings just by starlight.” [12:14]
• He cautions: even distant city lights over 100 km away cause a visible glow, so a nearby factory only 11 km away could devastate observations. [15:52]

Heritage Angle:

• Seidel emphasizes the universal, ancient human experience of looking at dark skies—now endangered: “It's really part of the human heritage that we are robbing us and future generations of, which is very sad.” [13:42]

Scientific Impact:

• Light pollution would hamper not just exoplanet studies but also meteor observations vital for planetary defense: “For example, planetary defense will be heavily impacted by this project. It's quite dangerous actually.” [17:04]

Activism:

• Thousands, including former observatory directors, have petitioned for the hydrogen factory to be relocated to preserve astronomical research capabilities. [11:40]

3. The Atlantic Meridional Overturning Circulation (AMOC): A Climate Safeguard?

[23:49–30:26]

Key Points:

• The AMOC, a colossal “conveyor belt” of ocean currents, is vital for Europe’s mild climate by transporting heat northward.
• There is concern it could collapse due to climate change, with catastrophic effects.
• Jonathan Baker and Met Office colleagues’ new modeling shows that powerful winds in the Southern Ocean act as a “pump,” stabilizing the system even as it weakens, making a total collapse this century unlikely.

Memorable Quotes:

• “The AMOC is a critical component of the ocean climate system...enough heat every five days to power the world for a year.” – Jonathan Baker [24:43]
• “In none of the models does the AMOC completely collapse. And so this gives us confidence that the AMOC is unlikely to collapse this century.” – Jonathan Baker [28:46]
• “But unlikely doesn't mean impossible. So we should be aware of these risks.” – Jonathan Baker [30:02]

Technical Details:

• Southern Ocean westerlies drive upwelling that sustains the AMOC, counterbalancing declines driven by Northern Atlantic changes.

4. Computers Woven into Clothes: The “Thread Computer” Revolution

[30:47–40:10]

Key Points:

• MIT team led by Joel Fink unveils a breakthrough: a computer embedded inside a stretchable fiber, with processor, memory, battery, and sensors—all integrated into clothing.
• This innovation could transform wearable technology and healthcare, e.g., smart garments that monitor health metrics for soldiers or civilians in harsh environments.

Memorable Quotes:

• “It is a fiber that has a complete computer in it. It has a processor, it has memory, it has communication... it has a battery.” – Joel Fink [31:59]
• “Computers today are designed to get in your way...The big idea here is being able to incorporate computation into the things that we're wearing, which are called clothes.” – Joel Fink [32:26]
• “There isn't a single instance of a stretchable computer that we know about. These fibers actually do stretch.” – Joel Fink [34:09]

Real-World Testing:

• Royal Marines have worn these garments in Arctic conditions to test for cold injury and manage caloric intake.
• “These fabrics are helping protect them, alert them to frostbite, and to help manage their caloric intake...our view of the future is that fabric is going to be on us 24 7, and it's actually going to monitor our health.” – Joel Fink [39:20]

Contextual Reflection:

• Fink links this step to a “Moore’s Law for fibers”: “Fibers haven't changed. How do you get a Moore's Law for fibers? How do you rapidly advance what a fiber is and what a fiber can do?” [36:18]

Notable Quotes & Timestamps

• “When you discover this kind of object...the Earth happens to be in that beam.” – Olivier Heino [03:46]
• “Now we know the orbit well enough to know that we'll not be in trouble in 2032.” – Olivier Heino [07:42]
• “All of this will basically make observing in many many instances completely pointless.” – Julius Seidel [02:12, 15:35]
• “For a cutting edge telescope, the impact is very significant. And it will basically destroy one of the last true dark sky sights in the world.” – Julius Seidel [15:52]
• “The AMOC is a critical component of the ocean climate system and it's a large system of ocean currents...enough heat every five days to power the world for a year.” – Jonathan Baker [24:43]
• “It is a fiber that has a complete computer in it. It has a processor, it has memory, it has communication, it has sensing in it, it has a battery.” – Joel Fink [31:59]
• “There isn't a single instance of a stretchable computer that we know about. These fibers actually do stretch.” – Joel Fink [34:09]

Timestamps for Key Segments

• 02:44 – Asteroid 2024 YR4 no longer a risk to Earth; interview with Olivier Heino
• 09:24 – Threat to Chilean night skies from green hydrogen plant; Julius Seidel on astronomical heritage and risks
• 23:49 – Atlantic Meridional Overturning Circulation; Jonathan Baker explains new climate modelling results
• 30:47 – “Thread computer” breakthrough; Joel Fink on wearable computing technology

Conclusion

This episode provides a multifaceted look at the frontiers of planetary defense, astronomy, climate science, and wearable technology. From the relief of averting a possible asteroid impact, to grassroots efforts to protect humanity’s last pristine night sky, to global ocean currents that stabilize our climate, and marvels of next-generation “smart” clothing—Science in Action delivers both scientific depth and the human stories behind the headlines.