In the Glass Beach, a beach in MacKerricher State Park near Fort Bragg, California, like the name tells you, you’d normally find too many glass pieces on the beach. These glass pieces that people often find in beaches like these, aren’t exactly those sharp shards of glass that are sharp enough to harm you. Rather they are physically and chemically weathered pieces of glass – round and small.
This type of glass is called sea glass and has been a fancy of those hobbyists who like collecting these pieces to make beautiful adornments.
This kind of glass, often found on some beaches usually starts as shards of broken glass from dump or other such sources. In about a span of 1-2 years, the tumbling and weathering makes these pieces smooth and rounded. And then they are collectively known as “genuine sea glass”
At this particular beach in California, the beach glass that has formed over the years, first started coming in when residents who lived close to the beach started dumping garbage into the beach. Local clean up services tried to clean up the mess, but most of it had already gone in for natural weathering by that time.
Soon after the clean-up services came around, the beach became a great place for hobbyists to collect these naturally weathered beautiful glass pieces. All the trash that was first thought to be a mess, now became a tourist attraction – Naturally weathered genuine sea glass was a thing of natural beauty now. And then this smuggling of sea glass by tourists had to stop. First the mess had to stop, now the mess being taken away by tourists had to stop.
And once the glass has started to go away, now there is a move to replace all the glass – that was once considered garbage!
Tectonic plates float at a certain elevation on Earth. This elevation is decided by what lies on the plate. So, depending on the density and thickness of the matter that is present on a tectonic plate, the plate adjusts its elevation to maintain a gravitational equilibrium between the uppermost solid mantle and the mechanically weak layer – Asthenosphere – which lies just below it. This is call Isostasy.
During the Ice age when the land masses were covered in ice sheets up to 3 kilometres thick, the landmasses got depressed. This was about 20,000 years ago (last part of the last ice age) when the massive ice weight made the mechanically weak mantle below the solid mantle, deform. Under pressure, the semi-solid-ish mantle below, started flowing to other places where the solid mantle was higher and allowed a greater place for the ductiley flowing mantle below the plates.
When this period ended, the glaciers started retreating and the landmasses started rising from depression. Now, since the mantle below is not totally liquid, it took a lot of time for it to rush back into place from where it was displaced by the primitive heavy ice covered land. In fact, at some places on Earth, this rebound is still happening – This is known as the post glacial rebound.
This can be seen in some parts of Finland, where the land around the Gulf of Bothnia rises about 1 cm each year to maintain the gravitational equilibrium between the Lithosphere (solid mass) and the Asthenosphere (the semi-solid-ish stuff below the solid mass)! As a result the land which was previously below sea, rises upwards and Finland expands in area – about 7 Square kilometres annually. This rise has been recorded by the BIFROST GPS network. And is estimated to continue for the next 10,000 years, not necessarily at the same rate.
Of course there are taller mountains than the Everest. Like if you consider the whole solar system, the tallest mountain is in Mars. It is about 2.5 times the height of Mt. Everest, and had it been on Earth, going to its peak would have required you to wear a space suit. It is about 21 km tall!
But here on earth, you’d think Mt. Everest is the tallest mountain. No, it is not. In fact, the peak of Mt. Everest is of course the Highest peak. So, it is the “Highest” mountain, not the “tallest”. The tallest one would be the Mauna Kea in Hawaii. Subtle differences, you see…
Tallest means – Measuring the mountain from its base to the peak. (Which seems pretty fair to me, but it isn’t the norm). Highest means – Measuring the mountain from the sea level to the peak.
Mountain peaks are measured from the sea level. Suppose a mountain is in the sea, the part of it which lies below the sea isn’t added to it’s height. So a mountain lying in the sea says, “unfair!”
Measuring sea level in turn is another complex problem because the sea isn’t at the same level everywhere. In fact, the sea level is much higher at the base of a mountain because the mountain’s mass increases the gravity and pulls the sea water making it higher there. Even if there isn’t any sea around mount Everest, the calculated sea level (higher than normal) is used as the base of the mountain. From this raised sea level to the peak, Mt. Everest measures 8,848 m.
This is how sea level is calculated:
Therefore, Mt. Everest is 8,848 meters tall, because there is no part of it which is under the sea (because there is no sea there). Also, Mt. Everest is 8,848 meters high because its peak is 8,848 meters from the calculated sea level.
Mauna Kea, a dormant volcano in Hawaii, is not popularly known because it’s peak is just 4207 m above the sea level. So, it is 4,207 meters high. Mt. Everest is much higher!
But the important thing to note is that a huge part of the volcano is under the sea level. In other words, its base is on the ocean bed, not on land. So, if measured from the base, it is 10,100 meters tall! That is more than 1.2 kilometres taller than the mount Everest.
That means, if there were no sea, Mauna Kea would have been a clear winner. Think of it this way – Suppose you cut both the mountain at their bases and place them on a huge flat land, Kea would be 1.2 kilometers higher! Given it is not a constant, I wonder why “sea level” is used as a standard to measure heights of mountains.
Clearly, Kea should be known better. School text books should at least have a mention of it.
Now if you think that is all I have to say about the highest and tallest things, you are wrong. There are all sorts of complex measurements we can do. What if, you start measuring the height of a mountain from the centre of the earth?
I don’t think that would be fair given the odd shape of earth – It is about 42 km farther across the equator than it is at the poles. That is too much distance to ignore. Had earth been a perfect sphere, this measurement would have made sense.
Nevertheless, let’s imagine that we have started measuring the height of a mountain peak by measuring its distance from the centre of the earth. In that case, Mt. Chimborazo, an ice-capped inactive volcano and the highest mountain in Ecuador, would have been the highest one. Even with a peak which is at an elevation of 6,268 meters from the sea level, it is still the most distant place from the centre of the earth. The peak of it is 6,384 km from the centre, while that of Mt. Everest is 6,382 km from the centre of the earth. In some way, even Chimborazo is taller than Mt. Everest. Still, we’re never taught about it in schools!
If there are any science teachers reading this, please tell these things to the kids. I’ll be honoured!
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