Recent comments in /f/askscience

CrustalTrudger t1_j4uqowa wrote

Reply to comment by horsetuna in Extinction of the Dinosaurs: What did I miss? by cakedayCountdown

> Finally once the crater was found, dated and confirmed it was accepted more or less.

This ignores a pretty active literature stream that has persisted since the impact hypothesis was proposed (and which continues to this day) that questions whether this was the cause (e.g., McLean, 1985, Courtillo & Cisowski, 1987, Pope, 2002, Keller et al., 2004, Fastovsky & Sheehan, 2005, Keller et al., 2020, etc.).

> some claim the impact caused the volcanic eruption, the shock waves converging on the far side of the planet where India would have been at the time

This is generally not what is argued for. What has been suggested is that the impact may have triggered a large pulse of Deccan Traps volcanism, but the timing of the start of Deccan Traps volcanism is demonstrably before the impact (e.g., Renne et al., 2013, Schoene et al., 2014, Renne et al., 2015) but timing of the main eruptive pulse remains controversial, i.e., it may have occurred sufficiently after the impact to be unrelated (e.g., Sprain et al., 2019).

> But less evidence for that

This is debatable, viable kill mechanisms tied to either event are pervasive in the literature (as are people pointing out issues with the alternative kill mechanism(s)). Arguably, the idea that neither the Deccan Traps nor the Chicxulub impact alone would have caused the extinction, but that the occurrence of both in short succession was enough to start the cascade is becoming closer to a consensus view (e.g., Petersen et al., 2016, but also the Renne et al., 2013 and Schoene et al., 2019 papers cited earlier). Similarly, there are suggestions that the K-Pg extinction was relatively protracted, perhaps occurred in pulses, and started before the impact, but with a pulse in extinction linked to the impact (e.g., Tobin, 2017)

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Aus_scientist t1_j4upg4e wrote

Reply to comment by kappusha in How many times mRNA transcript can be translated before it's degraded or something like that? by kappusha

Polysome profiling can give us an indication of translation kinetics. Basically, a transcript can have multiple ribosomes actively translating on it at once - so measuring this. Pairing this info with transcriptomic info you can get the rate of translation. And then knowing the transcript's degradation kinetics can give you an estimate.

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nog642 t1_j4unp9g wrote

Reply to What happens to the energy of sound in space? by full_hammer

Sound energy either stays in the medium (the boundary with space basically reflecting the sound back), or becomes kinetic energy of the molecules of the medium that are flung into space (and are just moving at a constant speed, not vibrating, so it can't really be called sound anymore). You'd get the former if the medium is a solid, the latter if the medium is air that is escaping into space.

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