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Gravity and Levity
Personal blog · gravityandlevity.wordpress.comscience
Gravity and Levity is a personal blog at gravityandlevity.wordpress.com about science. Since 2009, 42 different Hacker News readers have linked it 50 times, most often “Your body wasn’t built to last: Math of human mortality (2009)”. The last post was in 2020, but the archive is still widely read.
A blog about the big ideas in physics, plus a few other things
Most-linked posts?
- Your body wasn’t built to last: Math of human mortality (2009)9 people · 10 mentions · first linked 2012-12-20
- Your body wasn’t built to last: a lesson from human mortality rates9 people · 9 mentions · first linked 2009-08-02
- What if I were 1% charged? (2013)6 people · 6 mentions · first linked 2015-04-21
- How strong would a magnetic field have to be to kill you?5 people · 5 mentions · first linked 2015-01-12
- Why can’t I go faster than the speed of light?2 people · 2 mentions · first linked 2021-09-12
What Hacker News says?
I think the issue is that there are two conflicting populations on Hacker News: hackers/geeks/nerds in the traditional sense (who are here to talk about cool technology and such, and because the place is called "Hacker News") and entrepreneurs (who are here to talk about economics and politics and such, and because the place is run by a company that funds entrepreneurs). Being part of the first group, it's a bit str…
Comment linking /2015/01/12/how-strong-would-a-magnetic-field-have-to-be-to-kill-you/
on “The Human Toll of Flashbangs”Submitted Why can’t I go faster than the speed of light? as a story · 271 points
HN discussionObligatory link to yesterdays topic https://gravityandlevity.wordpress.com/2009/07/08/your-body-...
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “As we age, cancer rates go up as immune system winds down”Submitted Your body wasn’t built to last: a lesson from human mortality rates as a story · 266 points
HN discussionWe've gotten good interventions for a lot of things that will kill you that aren't old age. But if you've already managed to live to 90, your further life expectancy might not be much better today than it would have been in Ancient Greece. See http://gravityandlevity.wordpress.com/2009/07/08/your-body-w... for how bad things get when you age. Some kind of medical intervention that targeted the actual senescence mech…
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Hikikomori: Why are so many Japanese men refusing to leave their rooms?”Submitted What if I were 1% charged? (2013) as a story · 255 points
HN discussionYou can find the original, less ad-encrusted version of this article at http://gravityandlevity.wordpress.com/2009/07/08/your-body-w... .
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Your body wasn’t built to last: a lesson from human mortality rates”Submitted How strong would a magnetic field have to be to kill you? as a story · 221 points
HN discussionBrian Skinner, physicist and basketball analytics extraordinaire, wrote a really nice blog post about this 3.5 years ago [1]. Mining the comments from that post shows it's been banged around numerous times before that [2][3]. [1] https://gravityandlevity.wordpress.com/2009/04/02/parenting-... [2] http://www.nytimes.com/2009/04/21/science/21qna.html?_r=1 [3] http://web.archive.org/web/20071116094344/http://ourworld.c…
Comment linking /2009/04/02/parenting-and-the-feeling-of-time-my-eight-lifetimes/
on “Why time appears to speed up with age”Submitted Your body wasn’t built to last: a lesson from human mortality rates as a story · 151 points
HN discussionTwo points: (1) I haven't seen this article mentioned here: https://gravityandlevity.wordpress.com/2009/07/08/your-body-... I am not sure if the article addressed this model in particular, but I found it compelling. (2) It occurred to me that most of us don't fear death as much as becoming increasingly useless as we become older due to ill health and physical weakness. It would be not much fun living to be 200 if th…
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Physics Makes Aging Inevitable, Not Biology (2016)”Submitted What if I were 1% charged? (2013) as a story · 150 points
HN discussionThis links to a comment on the blog post, rather than the blog post itself. The link should be https://gravityandlevity.wordpress.com/2015/01/12/how-strong...
Comment linking /2015/01/12/how-strong-would-a-magnetic-field-have-to-be-to-kill-you/
on “How strong would a magnetic field have to be to kill you?”Submitted How strong would a magnetic field have to be to kill you? as a story · 115 points
HN discussionI found a much better explanation today on hacker news. Linking it here https://gravityandlevity.wordpress.com/2009/04/08/why-cant-i...
Comment linking /2009/04/08/why-cant-i-go-faster-than-the-speed-of-light-hints-from-electrodynamics/
on “Show HN: Relativity: A Modern Primer”Submitted How thick is the atmosphere? A derivation of the Boltzmann distribution as a story · 101 points
HN discussionWell, read this: https://gravityandlevity.wordpress.com/2009/07/08/your-body-... and then consider that a slight change in one of the exponents could have a significant effect on a person's quality of life.
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Fasting triggers stem cell regeneration of damaged, old immune system (2014)”Submitted Your body wasn’t built to last: Math of human mortality (2009) as a story · 88 points
HN discussion> If you were standing at arm's length from someone and each of you had one percent more electrons than protons[[0]] The latent energy of electromagnetic repulsion between the two of you (never mind between the parts of each of your bodies) would be a bit more than ((1%*80kg/2amu*electroncharge)^2 coulombconst / meter), or on the order of a megaton. Not megaton tnt , a megaton of just energy (comparable to a million…
Comment linking /2013/05/22/what-if-i-were-1-charged/
on “What a solid made of electrons looks like”Submitted Your body wasn’t built to last: a lesson from human mortality rates as a story · 85 points
HN discussionI think I read a short blog post about that a while before: https://gravityandlevity.wordpress.com/2015/01/12/how-strong... At least for how much would be safe.
Comment linking /2015/01/12/how-strong-would-a-magnetic-field-have-to-be-to-kill-you/
on “The most powerful MRI scanner in the world delivers its first images”Submitted Your body wasn’t built to last: a lesson from human mortality rates as a story · 51 points
HN discussionGravity and Levity presented in 2009 a much better intuitive model and mathematical principle that explains this bold pronouncement: https://gravityandlevity.wordpress.com/2009/07/08/your-body-...
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “What's the Longest Humans Can Live?”Submitted Body wasn't built to last: a lesson from human mortality rates (2009) as a story · 15 points
HN discussionMortality rates follow a Gompertz curve. This blog post explains it pretty well: http://gravityandlevity.wordpress.com/2009/07/08/your-body-w... There are many suspected specific reasons for why this is (telomeres shortening, mtDNA mutations, protein cross-links, etc), but it boils down to this: accumulating damage accumulates faster as self-repair mechanisms are damaged by accumulating damage.
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Why aren't the oldest living people getting any older?”Submitted What It Means and Doesn’t Mean to Get a Job in Physics (2019) as a story · 3 points
HN discussionReminded me of this great post from a while back, “What if I were 1% charged?”[0] looking at the consequences if you were to remove one out of every 100 electrons in your body. The answer: a Coulomb explosion powerful enough to rip the vacuum and generate antimatter from the void. [0]: https://gravityandlevity.wordpress.com/2013/05/22/what-if-i-...
Comment linking /2013/05/22/what-if-i-were-1-charged/
on “Coulomb explosion”Submitted How can electrons be “topological”? as a story · 3 points
HN discussionAwhile ago there was a wonderful little post about the probability distributions of human lifespan. The distributions fall off super-exponentially with age. What this means is that chances of someone living past 130 without major medical intervention is astronomically small. Even with medical intervention, it seems unlikely someone will live much past the 130 year barrier. Link: http://gravityandlevity.wordpress.com…
Comment linking /2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
on “Brazilian Billionaire Creates Plan to Beat Death”Submitted So is the universe made of tiny springs, or isn’t it? as a story · 3 points
HN discussion
