9 ms·

Every 202,500 Years, Earth Wanders in a New Direction

130 points by montrose 8y ago

everdev 8y ago
TLDR; Scientists believe the Earth's orbit oscillates between circular and more elliptical due to the gravitational pull from Jupiter (big) and Venus (close). It takes 405k years to complete a cycle.
- milankovic 8y ago
  Exactly, but what is new here? The duration of the complete cycle? Well, that number is new, to me at least, but the principle was well known before, I assume? I don't get it.. don't they teach basic astronomy in schools anymore?
  - flyGuyOnTheSly 8y ago
    >don't they teach basic astronomy in schools anymore? Not in Ontario, Canada, they don't... I had to get accepted into a university and then apply for first year astronomy to get any basic astronomy instruction whatsoever.
    - greglindahl 8y ago
      Many astronomers don't study astronomy until grad school! Physics is fundamental.
      - milankovic 8y ago
        What do you mean by fundamental here? For studying astronomy at an university? Then yes, agreed, but I am wondering about the very basic understanding of the principles at all, are you implying that kids today don't learn this anymore? You know, what our solar system is, what the earth is, and it's, well, shape..
        greglindahl 8y ago
        This particular cycle was not taught in the Astronomy PhD courses where I attended. Your comment near the top of this thread appears to claim that it's a part of 'basic astronomy'. That is not correct. The precession of the equinoxes is basic astronomy. (Ha. Firefox's spellcheck doesn't have "precession" in it.)
      - flyGuyOnTheSly 8y ago
        I did well in Physics in High School, and my instructor was massively interested in Astronomy, but he taught us very little about it.
    - milankovic 8y ago
      Wait.. are you serious? Guess I should consider myself lucky that I had a physics teacher who taught us about the thing that we stand on and live on, what it is, where it is, what's around and how our solar system works. Ha, I am really shocked now. Honestly, I can't believe this. I should probably not dare to ask someone on HN if they ever heard about the Milk Way or something.
      - labster 8y ago
        The Milky Way is a candy bar, everyone knows that! By your nick, I'm not surprised you know about Milankovitch cycles.
      - recursive 8y ago
        Or at least don't do it in such a dismissive way.
      - Milner08 8y ago
        You think this is equivalent to knowing about the Milky Way? You seem to have put some major significance on something that really has very little baring on our day to day lives. Im sure most countries teach a good deal about the solar system and the planets, It's taught at a very young age in the UK and its refined through the years of school to the point where you should have a good understanding of it all. But we never put any emphasis on this. You know why? Its irrelevant at that level. Unless you are studying for a degree or even higher this won't have any baring on what you are learning.
  - ozmbie 8y ago
    It mentiones why this is useful: > it will give scientists a much more accurate method of dating prehistorical events — the dates of fossils, for example. > “The dream is have a framework independent of the fossils that you can plug the fossils into and see more interesting things — the coexistence of disparate forms, or of similar forms widely separated in location. Now we can place things more accurately in time rather than depending on the fossils to tell us what the time is.” It's also fascinating to see how it was done: >By comparing the amount of decay of uranium to that of lead trapped in zircon, the layers in the Arizona core can be dated quite accurately.
zw123456 8y ago
The result of which is ... ? Does this lead to some occurrence such as a mass extinction or something of that nature? Seems interesting.
- deleted 8y ago
  [deleted]
- Alex3917 8y ago
  > Does this lead to some occurrence such as a mass extinction or something of that nature? I have no doubt there will be dozens of astrology videos about this on YouTube within a few days.
- mygo 8y ago
  it would be interesting to see how this correlates with known glaciation periods.
- matte_black 8y ago
  As the orbit elongates we experience greater variation in distance from the sun. At the extremes, we get colder winters and hotter summers. Perhaps another explanation for climate change.
  - thaumasiotes 8y ago
    Why would more eccentricity lead to colder winters and hotter summers in each hemisphere? How would that work?
    - LoSboccacc 8y ago
      yeah makes little sense since the earth is closer to the sun in january. if anything higher eccentricity should reduce seasonal differences. (seasonal differences being driven mostly by earth tilt, not distance from sun)
- cryptonector 8y ago
  At times of higher eccentricity you get more pronounced differences between summer and winter. If this coincides with a glacial period (and it has) that probably means that the glacial period sets in faster / is colder than when the orbital eccentricity is low -- but it also means that interglacials set in faster and are warmer.
geuis 8y ago
Better article with more details and a link to the relevant paper https://www.universetoday.com/139198/jupiter-and-venus-change-earths-orbit-every-405000-years/ https://www.universetoday.com/139198/jupiter-and-venus-chang...
- ChuckMcM 8y ago
  I expect this is the danger quote "“The climate cycles are directly related to how Earth orbits the sun and slight variations in sunlight reaching Earth lead to climate and ecological changes,” said Kent, who studies Earth’s magnetic field. “The Earth’s orbit changes from close to perfectly circular to about 5 percent elongated especially every 405,000 years.” which comes from here (https://news.rutgers.edu/earth%E2%80%99s-orbital-changes-have-influenced-climate-life-forms-least-215-million-years/20180502#.WvSKMiBlDIX https://news.rutgers.edu/earth%E2%80%99s-orbital-changes-hav...)
mkempe 8y ago
The change in orbital shape was already known as one of the Milankovitch cycles [1]. This study seems to give us the most precise measurement. In the context of climate change, when Earth's orbit becomes more eccentric (our path over the next 200k years) seasonal changes increase in magnitude. [1] https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity) https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_sh...
- milankovic 8y ago
  It's Milanković actually, and that guy also has his own entry on Wikipedia: https://en.wikipedia.org/wiki/Milutin_Milankovi%C4%87 https://en.wikipedia.org/wiki/Milutin_Milankovi%C4%87 I'm repeating myself again here, but it's funny to see when your nickname on HN suddenly becomes relevant. * EDIT: Just because it is apparently not clear enough. No, this is not a coincidence, no, my real name is not milankovic or similar, and yes, I've chosen my handle in honor of this scientist. * But you are right, I am completely with you in regard to this certain point: > The change in orbital shape was already known as one of the Milankovitch cycles It was already known, yeah. Or so I (we?) assumed. I'm just some poor slob who visited an ordinary school, not an astronomer, not special in any other way, and I still remember that we learned this stuff back then. Astronomy 101. I bring this up in a comment here, and all I get is downvotes. Which tells a lot about HN, I think. The context of climate change, now that is the really interesting question. I am really fascinated to see that Milankovic is finally becoming more relevant today. (Ask about a famous Serbian scientist, and everyone can mention Tesla. Ask for the next one, and observe. But that's a good test, to see who really gives a damn about science) Interestingly, I did a Ctrl+F on that NYT article for the name, and nothing came up. They even fail to mention the relevance to climate change at all, which is, as everyone knows, totally not an important current issue in, well, 2018; and maybe it is just me, but one would assume that this could be something newsworthy. Again, the fake news NYT utterly fails once more. I should really not be surprised at this point.
  - flukus 8y ago
    > I bring this up in a comment here, and all I get is downvotes. Which tells a lot about HN, I think. You've managed to be dismissive of everyone that knows slightly less than you, everyone that didn't cover this in school, and at the same time dismissive of everyone that knows much more, climate scientists. Apparently you think this is universal knowledge but somehow has escaped the attention of climate scientists.
milankovic 8y ago
Oh my god, not again. I mean, yes. I thought that was universal knowledge, oscillation in earth's orbit? (nickname finally relevant, by the way) This is also why climate science is (mostly) junk science, don't let them get away without accounting for stuff like this in the future..
- saagarjha 8y ago
  > I thought that was universal knowledge, oscillation in earth's orbit You thought wrong, then. This isn't a common thing that's taught in schools here, and many people go through formal education without learning it.
- justherefortart 8y ago
  OMG not everyone has the same education as me! OH THE HUMANITY!
palisade 8y ago
I made a thing. To wrap my head around the Milankovitch cycles. https://i.imgur.com/V3RIKL5.png https://i.imgur.com/V3RIKL5.png
gwbas1c 8y ago
Based on where we are in the Milankovitch cycle, should we be getting warmer or colder? (I keep checking the comments of this article hoping that someone knowledgable can explain how this impacts the climate.)
- noiv 8y ago
  NASA to the rescue: https://earthobservatory.nasa.gov/Features/Milankovitch/ https://earthobservatory.nasa.gov/Features/Milankovitch/ Basically it's not measurable within a lifetime and the signal of human interaction with the climate is magnitudes higher.
  - mkempe 8y ago
    It is extravagant and ludicrous to claim that the signal of human influence (CO2 ppm?) on the climate is magnitudes higher than that of the Milankovitch cycles -- which have been driving the regular glaciations and interglacials over the last 3 million years.
    - lstroud 8y ago
      That said, we do use ice cores from periods that would cross multiple of these cycles. If these cycles change how we estimate those values, then the statistical models we’ve built based on them will need to adjust accordingly. So, it’s not that it doesn’t have an impact, just that the impact probably doesn’t change the trend line.
    - noiv 8y ago
      Do the math...
- mkempe 8y ago
  There are multiple cycles in that theory, not just one, so the influence on our climate depends on the periods of all these cycles, and involves potential amplification due to their harmonies. The largest observed signal in the geological record of the last 3 million years is a ~100k cycle of interglacials within an Ice Age. Accordingly we should expect the current interglacial to end "soon" and enormously thick ice sheets shall grow again -- we're 12k years into the Holocene; the last interglacial lasted 15k years.
early 8y ago
Paywall articles should be banned here

130 points by montrose 8y ago

TLDR; Scientists believe the Earth's orbit oscillates between circular and more elliptical due to the gravitational pull from Jupiter (big) and Venus (close). It takes 405k years to complete a cycle.

milankovic 8y ago
Exactly, but what is new here? The duration of the complete cycle? Well, that number is new, to me at least, but the principle was well known before, I assume? I don't get it.. don't they teach basic astronomy in schools anymore?
- flyGuyOnTheSly 8y ago
  >don't they teach basic astronomy in schools anymore? Not in Ontario, Canada, they don't... I had to get accepted into a university and then apply for first year astronomy to get any basic astronomy instruction whatsoever.
  - greglindahl 8y ago
    Many astronomers don't study astronomy until grad school! Physics is fundamental.
    - milankovic 8y ago
      What do you mean by fundamental here? For studying astronomy at an university? Then yes, agreed, but I am wondering about the very basic understanding of the principles at all, are you implying that kids today don't learn this anymore? You know, what our solar system is, what the earth is, and it's, well, shape..
      - greglindahl 8y ago
        This particular cycle was not taught in the Astronomy PhD courses where I attended. Your comment near the top of this thread appears to claim that it's a part of 'basic astronomy'. That is not correct. The precession of the equinoxes is basic astronomy. (Ha. Firefox's spellcheck doesn't have "precession" in it.)
    - flyGuyOnTheSly 8y ago
      I did well in Physics in High School, and my instructor was massively interested in Astronomy, but he taught us very little about it.
  - milankovic 8y ago
    Wait.. are you serious? Guess I should consider myself lucky that I had a physics teacher who taught us about the thing that we stand on and live on, what it is, where it is, what's around and how our solar system works. Ha, I am really shocked now. Honestly, I can't believe this. I should probably not dare to ask someone on HN if they ever heard about the Milk Way or something.
    - labster 8y ago
      The Milky Way is a candy bar, everyone knows that! By your nick, I'm not surprised you know about Milankovitch cycles.
    - recursive 8y ago
      Or at least don't do it in such a dismissive way.
    - Milner08 8y ago
      You think this is equivalent to knowing about the Milky Way? You seem to have put some major significance on something that really has very little baring on our day to day lives. Im sure most countries teach a good deal about the solar system and the planets, It's taught at a very young age in the UK and its refined through the years of school to the point where you should have a good understanding of it all. But we never put any emphasis on this. You know why? Its irrelevant at that level. Unless you are studying for a degree or even higher this won't have any baring on what you are learning.
- ozmbie 8y ago
  It mentiones why this is useful: > it will give scientists a much more accurate method of dating prehistorical events — the dates of fossils, for example. > “The dream is have a framework independent of the fossils that you can plug the fossils into and see more interesting things — the coexistence of disparate forms, or of similar forms widely separated in location. Now we can place things more accurately in time rather than depending on the fossils to tell us what the time is.” It's also fascinating to see how it was done: >By comparing the amount of decay of uranium to that of lead trapped in zircon, the layers in the Arizona core can be dated quite accurately.

zw123456 8y ago

The result of which is ... ? Does this lead to some occurrence such as a mass extinction or something of that nature? Seems interesting.

deleted 8y ago
[deleted]
Alex3917 8y ago
> Does this lead to some occurrence such as a mass extinction or something of that nature? I have no doubt there will be dozens of astrology videos about this on YouTube within a few days.
mygo 8y ago
it would be interesting to see how this correlates with known glaciation periods.
matte_black 8y ago
As the orbit elongates we experience greater variation in distance from the sun. At the extremes, we get colder winters and hotter summers. Perhaps another explanation for climate change.
- thaumasiotes 8y ago
  Why would more eccentricity lead to colder winters and hotter summers in each hemisphere? How would that work?
  - LoSboccacc 8y ago
    yeah makes little sense since the earth is closer to the sun in january. if anything higher eccentricity should reduce seasonal differences. (seasonal differences being driven mostly by earth tilt, not distance from sun)
cryptonector 8y ago
At times of higher eccentricity you get more pronounced differences between summer and winter. If this coincides with a glacial period (and it has) that probably means that the glacial period sets in faster / is colder than when the orbital eccentricity is low -- but it also means that interglacials set in faster and are warmer.

geuis 8y ago

Better article with more details and a link to the relevant paper https://www.universetoday.com/139198/jupiter-and-venus-change-earths-orbit-every-405000-years/ https://www.universetoday.com/139198/jupiter-and-venus-chang...

ChuckMcM 8y ago
I expect this is the danger quote "“The climate cycles are directly related to how Earth orbits the sun and slight variations in sunlight reaching Earth lead to climate and ecological changes,” said Kent, who studies Earth’s magnetic field. “The Earth’s orbit changes from close to perfectly circular to about 5 percent elongated especially every 405,000 years.” which comes from here (https://news.rutgers.edu/earth%E2%80%99s-orbital-changes-have-influenced-climate-life-forms-least-215-million-years/20180502#.WvSKMiBlDIX https://news.rutgers.edu/earth%E2%80%99s-orbital-changes-hav...)

mkempe 8y ago

The change in orbital shape was already known as one of the Milankovitch cycles [1]. This study seems to give us the most precise measurement. In the context of climate change, when Earth's orbit becomes more eccentric (our path over the next 200k years) seasonal changes increase in magnitude. [1] https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity) https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_sh...

milankovic 8y ago
It's Milanković actually, and that guy also has his own entry on Wikipedia: https://en.wikipedia.org/wiki/Milutin_Milankovi%C4%87 https://en.wikipedia.org/wiki/Milutin_Milankovi%C4%87 I'm repeating myself again here, but it's funny to see when your nickname on HN suddenly becomes relevant. * EDIT: Just because it is apparently not clear enough. No, this is not a coincidence, no, my real name is not milankovic or similar, and yes, I've chosen my handle in honor of this scientist. * But you are right, I am completely with you in regard to this certain point: > The change in orbital shape was already known as one of the Milankovitch cycles It was already known, yeah. Or so I (we?) assumed. I'm just some poor slob who visited an ordinary school, not an astronomer, not special in any other way, and I still remember that we learned this stuff back then. Astronomy 101. I bring this up in a comment here, and all I get is downvotes. Which tells a lot about HN, I think. The context of climate change, now that is the really interesting question. I am really fascinated to see that Milankovic is finally becoming more relevant today. (Ask about a famous Serbian scientist, and everyone can mention Tesla. Ask for the next one, and observe. But that's a good test, to see who really gives a damn about science) Interestingly, I did a Ctrl+F on that NYT article for the name, and nothing came up. They even fail to mention the relevance to climate change at all, which is, as everyone knows, totally not an important current issue in, well, 2018; and maybe it is just me, but one would assume that this could be something newsworthy. Again, the fake news NYT utterly fails once more. I should really not be surprised at this point.
- flukus 8y ago
  > I bring this up in a comment here, and all I get is downvotes. Which tells a lot about HN, I think. You've managed to be dismissive of everyone that knows slightly less than you, everyone that didn't cover this in school, and at the same time dismissive of everyone that knows much more, climate scientists. Apparently you think this is universal knowledge but somehow has escaped the attention of climate scientists.

milankovic 8y ago

Oh my god, not again. I mean, yes. I thought that was universal knowledge, oscillation in earth's orbit? (nickname finally relevant, by the way) This is also why climate science is (mostly) junk science, don't let them get away without accounting for stuff like this in the future..

saagarjha 8y ago
> I thought that was universal knowledge, oscillation in earth's orbit You thought wrong, then. This isn't a common thing that's taught in schools here, and many people go through formal education without learning it.
justherefortart 8y ago
OMG not everyone has the same education as me! OH THE HUMANITY!

palisade 8y ago

I made a thing. To wrap my head around the Milankovitch cycles. https://i.imgur.com/V3RIKL5.png https://i.imgur.com/V3RIKL5.png

gwbas1c 8y ago

Based on where we are in the Milankovitch cycle, should we be getting warmer or colder? (I keep checking the comments of this article hoping that someone knowledgable can explain how this impacts the climate.)

noiv 8y ago
NASA to the rescue: https://earthobservatory.nasa.gov/Features/Milankovitch/ https://earthobservatory.nasa.gov/Features/Milankovitch/ Basically it's not measurable within a lifetime and the signal of human interaction with the climate is magnitudes higher.
- mkempe 8y ago
  It is extravagant and ludicrous to claim that the signal of human influence (CO2 ppm?) on the climate is magnitudes higher than that of the Milankovitch cycles -- which have been driving the regular glaciations and interglacials over the last 3 million years.
  - lstroud 8y ago
    That said, we do use ice cores from periods that would cross multiple of these cycles. If these cycles change how we estimate those values, then the statistical models we’ve built based on them will need to adjust accordingly. So, it’s not that it doesn’t have an impact, just that the impact probably doesn’t change the trend line.
  - noiv 8y ago
    Do the math...
mkempe 8y ago
There are multiple cycles in that theory, not just one, so the influence on our climate depends on the periods of all these cycles, and involves potential amplification due to their harmonies. The largest observed signal in the geological record of the last 3 million years is a ~100k cycle of interglacials within an Ice Age. Accordingly we should expect the current interglacial to end "soon" and enormously thick ice sheets shall grow again -- we're 12k years into the Holocene; the last interglacial lasted 15k years.

early 8y ago

Paywall articles should be banned here