Wednesday, April 3, 2013

Phoebe and Newgrange - Suppose two earth rings

What about 20th century warming?  It looks kind of like a Ring thing because just like the Ice Age, the 20th century climate trends are different in summer and winter.  For a while there seemed to be more warming in winter than summer, and lately, it is cooling in winter but not summer.  This kind of seasonal difference yells, "Rings!"  (See visualization.)  Likewise, warming seemed to be mainly a matter of warming up the daily cold minimum, not so much the daily high.  An equatorial ring would do that too.   And 20th century trends seemed to vary with latitude, another distinction ring shading would inevitably make.  Could 20th century warming, such as it was, have been caused by a fading ring around the equator?  Maybe a ring that comes and goes when the Sun is more or less active?

Visualization of Earth with an equatorial ring

There's a problem, though - there was 20th century warming in the summers too,  albeit weak and inconsistent.  Trends were not only in winters.  And an equatorial ring can't do that.

But a few years ago, a new kind of ring was found at Saturn, a ring not around Saturn's equator but significantly tilted, a ring in the plane of Saturn's moon Phoebe.  Here is a terrific graphic from BBC about that discovery:

Saturn's Phoebe ring - a graphic from the BBC.

That was a big discovery, really big.  Up until that discovery, all the planetary rings were around equators - Saturn's, Jupiter's, Neptune's, Uranus's.  (I've embedded a video below.  Press refresh if you just see a big blank.  That seems to help.)

A computer visualization of Neptune's ring, which is around its equator.

Maxwell explained in 1859 why rings are likeliest around the equator.  It's because, no matter where dust and rocks come from, as they get near a planet they will interact with the planet's atmosphere and with stuff thrown up from the planet, all of which is rotating along with the planet.  Directly or indirectly, over time, any material orbiting a planet will be smacked again and again until its orbit is also aligned with the rotation of the planet.  Imagine somebody trying to drive slantwise back and forth across Route I-95.  The car would be broken up and its pieces would be carried along with traffic.  So imagine the equatorial plane as the I-95 of the planet-moon-rings system.

Yet somehow here is this new Phoebe ring.  How is it possible?  Maybe because it's remote?  Maybe because it's young?

Anyway - what exists is possible.  And if we add a Moon-plane ring to the Earth ring hypothesis, then we are able to get out of the hypothesis an explanation for any sum of:  (a) global trends in winter only, from the equatorial ring, and also (b) global trends, erratic and inconsistent, and possibly in the opposite direction from the winter trends, that affect any part of the year. How convenient.  A ring system fading and brightening and fading again can't explain absolutely any arbitrary thing, but it can explain more things than a one-ring system can and thus far it appears it can explain the trends that actually happened.

Visualization of Earth with two rings -
one in the plane of the equator and one in the plane of the Moon's orbit

There's another reason to look for a two-ring Earth system:   Newgrange.  About five to seven thousand years ago, whoever was then living in Ireland built about a lot of stone monuments with rock carvings all over them.  Among these:  Newgrange, Loughcrew, Fourknocks, Knowth, Tara.....  Besides the very big sites, there are also dozens of smaller ones, also with carvings.

A smaller site near Loughcrew.  Photo by Renee Tatusko.

Its carvings.  Photo by Renee Tatusko.

This whole phenomenon is somehow connected to astronomy.  In all these places, similar motifs were carved again and again: sawtooth lines that seem to be be counting out days of the month, and spirals that seem to represent the sun in the sky approaching solstice and moving away, and some starry shapes.

Also Loughcrew.  Photo by Renee Tatusko.

Among all these is an unexplained motif of loops.  Ireland's astronomical sites are covered with carvings of loops, heaps and piles of loops.   They are obviously important because this motif is often repeated, but nobody can work out what the carvers had in mind.  

What is this about?   Photo by Renee Tatusko.

Some people think the loops were carved by people on drugs trying to recap their hallucinations afterward.   Maybe. But it's weird they're there among a lot of hardworking astronomy.  Instead, maybe the ancients were carving things in the sky that we don't recognize because we don't see those things anymore.  Such as rings, which would have been brighter thousands of years ago back nearer the Ice Age.

Here is a visualization of how the sky at Newgrange would look if the Earth had a two-ring system.   (The visualization is for September 2012, not 5000 BC, but it doesn't matter much.)  The video is slow coming up sometimes, but pressing refresh seems to help.
Sky position of a hypothetical two-ring Earth system, for 54N, September 2012.  View is due south.

In this video, you see one set of loops that never moves, and another one that moves constantly.  The never-moving loops are the sky position of an equatorial ring.  The always-moving set of loops are the sky position of a ring in the plane of the Moon's orbit.  This is parallel to the ecliptic (the path of the sun on the sky, runs through the zodiac).

Taken altogether, the total picture does indeed look sort of like heaps and piles of rings.  That, apparently, is the look of a two-ring system, and to me it does look a bit like carvings at Newgrange.

Next:  Haystack and YORP - Very dusty rings.

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Thursday, March 28, 2013

Climate change - Suppose an Earth ring...

It was my father's idea.  He was a lunar scientist at NASA.  In 1980, he published a note in Nature, saying out that if the Earth once had a ring like Saturn's, the shade cast on Earth by the ring could have caused an Ice Age.  This would explain a strange thing about the Ice Ages, namely that the climate mainly cooled in winter only.

Here is a video that shows why a ring in the equatorial plane, like Saturn's famous bright ring, shades only winter.

The idea he published was strictly limited, but when he and Mom talked about it at the dinner table, they used to speculate about what that ring might have looked like in the sky.  After all, the last Ice Age faded away about 11,000 years ago, so there would have been people to see a bright Ring if it were in the sky then.  Eleven thousand years ago is prehistoric, but not by very much.  If there once were a ring in the sky, it might still be remembered in legends.  What legends would those be?  They thought maybe dragons?  Snakes?  That ate the sun?  There are lot of legends like that.

Another thing they talked about was how dangerous the Moon might be.  A really important point about Earth rings is that they can't last unless the Moon is active, shooting out rocks or dust or lava occasionally to keep the rings supplied with fresh material, because older material continually falls to Earth.  There aren't long-term stable orbits in the Earth-Moon system.  On one hand, if the Moon isn't active, there's no ring; on the other hand, if there's a ring, the Moon is active.

Could the Moon be active enough to maintain an Earth ring?  Most think the Moon is dead, but my father saw persistent, unresolved difficulties with the idea of a dead Moon (like the fact that people keep seeing red flashes there), and thought that people were settling too easily into a dead-Moon consensus, and ignoring a problem.

Maybe the Moon isn't dead, and if that's the case, we would really want to know about that.  It would be exciting if the Moon erupted and sent a lot of dust and rocks our way, falling into the atmosphere in flames and so on.  It would be just like when the dinosaurs died.  Actually, that's how my father thought the dinosaurs likely did die.  If the Moon were the source of material coming our way, we would get just a few days notice of it.
   Dinosaur hall at Museum of Natural History, DC.  This is their photo.

On a longer time frame, the ring could slowly cycle downward and fall to earth as dust storms.  There's a dinosaur fossil called Oviraptor that was found in the Chinese desert, and what's weird is, the dinosaur was found with its wings spread over its eggs. For all anyone can tell, it appears that the dinosaur just sat there and died for no apparent reason and the sand eventually piled up around it and buried it. There are a lot of other fossils that seem that way (I read about them in The Secret Life of Dust, which has references).

What would make perfect sense out of Oviraptor is if a big dust storm started, and if the dinosaur was used to those, so it spread its wings in protection over its nest, and waited there for the storm to be over.  But this time, the dust storm went on and on and on and on and finally both mother and nest and a lot of other animals of the same kind drowned in sand. There would be no sign of the killer event, because the whole area is sand anyway, due to its long history of similar though smaller events.

Thinking about those things is the origin of this program - an exploration of whether the Earth once had a ring and still might have one today, still driving weather, and while we're at it, remembering that if the Earth has a ring, then the Moon is geologically active and a potential concern - able to launch not only flaming rocks through the atmosphere but also vast dust clouds.  Dust storms that we think of as topsoil moving around, might not be, and sometimes, the storms could be really big.

Still, I believe in Providence, so I think the thing is to be reasonable and assess facts and manage things logically and in the best way we can.

As the book of Wisdom puts it, about a person setting off through the wild waves on an unsound boat, your providence, O Father! guides it, for you have furnished even in the sea a road, and through the waves a steady path, showing that you can save from any danger, so that even one without skill can embark.

That's just about our situation here.  So, onward, rational and fearless.

Next time:  Visit to Newgrange

The laborer being worthy of her hire,