Did Dark Matter Kill the Dinosaurs? | Summary and Q&A

TL;DR

Dark matter, a mysterious material in the universe, may have played a role in causing extinction events, such as the one that killed the dinosaurs.

Key Insights

• ❓ The periodicity of impact events on Earth suggests the existence of a cause in the outer solar system.
• 🪐 The presence of potential planets like Planet 9 and Planet 10 in the outer solar system could explain the perturbation of comets.
• 🌟 Passing stars like Scholz's star may also perturb comets, but the likelihood of comets hitting Earth from this encounter is low due to the long timescale.
• 🖐️ Dark matter, although largely undetected, could have played a role in causing the Cretaceous-Paleogene extinction event that wiped out the dinosaurs.
• 🦕 The nature of the impactor that killed the dinosaurs, whether asteroid or comet, is still uncertain, making it difficult to determine the exact perturber.
• 🏛️ Dark matter settling into concentrations is currently deemed unlikely due to its weak interaction, but different classes or behaviors of dark matter cannot be ruled out.
• 🧑‍🏭 The possibility of other unknown factors causing extinction events suggests that our current understanding of the universe may be limited.

Transcript

One of the biggest questions regarding the bombardment of earth by asteroids or comets is if it’s just a more or less random chance event where an asteroid happens to hit us, or if it’s actually non-random and is caused by something in the outer solar system perturbing comets and sending hails of them into the inner solar system periodically. There... Read More

Questions & Answers

Q: What are the two ways that asteroid bombardment on Earth could occur?

The first possibility is the existence of a large body in the outer solar system that deflects comets towards Earth periodically. The second possibility is past stellar encounters, where a passing star like Scholz's star perturbs comets in the Oort cloud and sends them towards Earth.

Q: Can passing black holes or brown dwarfs be potential perturbers of comets?

Passing black holes or brown dwarfs that are not bound to the Sun are unknowns in terms of their ability to perturb comets. It is unclear whether their gravitational influence could affect comets in a way that sends them towards Earth.

Q: How does dark matter contribute to the overall gravity of galaxies?

Dark matter is invoked because most galaxies don't behave as they should based on the amount of visible matter they contain. There must be an otherwise undetectable, invisible form of matter, such as dark matter, that contributes to the overall gravity of galaxies, allowing them to hold together.

Q: How could dark matter perturb comets and potentially cause extinction events?

The idea is that as the Sun moves independently in the Milky Way's spiral arms, it also bobs up and down in relation to the galactic plane. If dark matter concentrations vary in regions of denser matter, comets could get perturbed by dark matter's gravity and be sent towards Earth periodically.

Summary & Key Takeaways

• The question of whether asteroid bombardment on Earth is a random event or caused by something in the outer solar system has intrigued scientists.

• Two possibilities include the existence of large bodies in the outer solar system that deflect comets towards Earth periodically and past stellar encounters.

• Recent research suggests that dark matter, a form of invisible matter, may have perturbed comets and caused extinction events, although the evidence for this is weak.