Recent comments in /f/askscience

adaminc t1_j2exfz1 wrote

Reply to comment by No_Stretch_3899 in Do cats and dogs see things under blacklight the same as we do? by Rowsdower32

The human retina can actually see UV light, but the lens blocks most of it. If you get cataract surgery, and get an artificial lens implanted, it's possible that you start seeing that UV light, it appears as white though.

It's also dangerous, and you'll need to wear sunglasses outdoors for the rest of your life, during the daytime.

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theCumCatcher t1_j2ew7u5 wrote

Reply to comment by _AlreadyTaken_ in How much does the liquid magma of the Earth affect it's surface temperature? by tripperfunster

this is true. I worded my answer poorly.

the sun would irradiate anything alive on the surface while high energy particles whittled away at the ozone, making it worse.

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NOT TO MENTION, you are absolutely right with venus. it has gravty on its side, there

if we had a weaker pull, like mars, then in that case i think it would erode the atmosphere completely

I'll direct you to look at the MAVEN discoveries, to verify me there

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CrustalTrudger t1_j2evjxm wrote

Reply to Does radioisotope migration affect radiometric dating and if so how do we correct for it? by magixsumo

> They claimed the paper shows how radiometric dating is unreliable, because radioisotopes can be leeched or absorbed which would through off the ratio of daughter to parent isotope.

An important aspect here is that not only are these considering relatively rare areas (i.e., areas influenced by radioactive testing and/or natural reactors like Oklo), they are (1) mostly tracing radionuclides that are not used in radiometric dating and (2) more importantly considering migration into and out of material (i.e., minerals) that are not typically used for radiometric dating. That radionuclides are soluble and thus easily mobilized out of oxides like what this paper focuses on is precisely a reason why many of these minerals are not considered suitable for geochronology. Minerals that we actually use regularly for geochronology (e.g., zircon, monazite, apatite, etc.) are used in part because they tend to be relatively resistant to these kind of effects.

Additionally, the underlying premise seems to be that geochronologists just uniformly accept the assumptions of closed-system behavior when in fact we routinely consider, and test for, open-system behavior as a matter of course in most analyses (e.g., Schoene et al., 2013). The degree to which we are concerned about open-system behavior, and potential remedies or corrections, depend on the method. We generally expect that U-Pb dating in zircon will reflect closed-system behavior, but still almost always check via measuring both ^(238)U-^(206)Pb and ^(235)U-^(207)Pb ages whereas we expect the possibility of open-system behavior of something like ^(234)U-^(230)Th dating in carbonates is relatively high and do a variety of things to check whether dates are valid or influenced significantly by open-system behavior.

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a_wild_redditor t1_j2eojab wrote

Reply to comment by enderjaca in How did Rutherford arrive at gold foil as the best choice for his particle experiments? by Poltibolsa

Gold leaf is readily available very thin, it can be well under 1μm. The lead sheet or foil I'm familiar with is much thicker since common uses require its density (counterweighting as you mentioned), its radiation shielding properties, and/or its easy formability by hand while holding its shape afterwards.

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