edition.cnn.com
Supernovas May Have Triggered Two Mass Extinctions on Earth
A new study suggests that two of Earth's biggest mass extinction events might have been caused by nearby supernovas, based on calculations of supernova rates from the past billion years and their potential impact on Earth's ozone layer.
- How might a nearby supernova cause a mass extinction event, and what specific evidence could support this hypothesis?
- The study connects the calculated supernova rate within 65 light-years of the sun over the past billion years with cataclysmic events that caused mass extinction. These events include the Late Devonian extinction (372 million years ago) and the Late Ordovician extinction (445 million years ago), potentially linked to ozone layer depletion from nearby supernovae. This hypothesis is supported by the occurrence of glaciation during the Late Ordovician, a potential consequence of a nearby supernova.
- What is the estimated rate of supernovas that could impact Earth, and how might this relate to the timing of known mass extinction events?
- New research suggests that nearby supernovas may have contributed to two of Earth's largest mass extinctions. Calculations based on the European Space Agency's Gaia space telescope data estimate a rate of 2.5 supernovas affecting Earth every billion years, potentially causing ozone depletion and triggering a chain of events leading to mass extinction.
- What are the limitations of this study, and what future research is needed to confirm or refute the link between supernovas and mass extinctions?
- Future research should focus on finding evidence to support the hypothesis. Specifically, identifying isotopes like iron-60 or plutonium in the geological record from the periods of the suggested mass extinction events would provide strong evidence of a supernova. Further investigation into ozone depletion levels in relevant rock and sediment layers could also contribute to confirming this theory.
Cognitive Concepts
Framing Bias
The headline and introduction emphasize the supernova theory as a potential explanation for unexplained mass extinctions. While presenting it as a hypothesis, the framing gives significant weight to this theory without equal emphasis on other possible causes. This might lead readers to overestimate the likelihood of supernovae being the primary factor. The article's structure prioritizes the supernova theory, potentially overshadowing other contributing factors or uncertainties.
Language Bias
The language used is largely neutral, but there are instances of words that may subtly influence the reader. For example, phrases like "violent supernovas" and "devastating effects" have a strong emotional impact. More neutral alternatives could include "powerful supernovas" and "significant effects." The repeated use of "cataclysmic" might also be considered overly dramatic.
Bias by Omission
The article focuses heavily on the supernova theory but omits discussion of other potential causes for the mass extinctions, such as volcanic eruptions or other environmental factors. While acknowledging limitations of space, a brief mention of competing theories would improve the balance and provide a more complete picture. The lack of detailed discussion on the dating of supernovae compared to extinction events is a notable omission.
False Dichotomy
The article presents a potential link between supernovas and mass extinctions as a hypothesis without fully exploring the complexities involved. It doesn't sufficiently acknowledge the possibility of multiple contributing factors or the lack of definitive proof. The framing may unintentionally lead readers to see this as a simpler explanation than may actually be the case.
Sustainable Development Goals
The research suggests that supernovas may have caused mass extinction events on Earth, wiping out a significant portion of land-based species during the Late Devonian extinction. The destruction of the ozone layer, a potential consequence of nearby supernovas, could have led to increased radiation exposure, harming terrestrial ecosystems.