Is high tide at all places of the Earth or is it low tide at the opposite side?

Question

When it is high tide at one location of the Earth, is it low tide at exactly the opposite side of the Earth ? If so, then does it mean that gradually high tide turn towards low tide when you start going to other side of the Earth. If No, that is, the High tide is unformly at all sides of the Earth, then how can we say that Moon influences the High Tide ? It is near to the Earth only on one side.

I have observed that when the moon is on my overhead, it is NOT necessarily a high tide below. Then how can we say that Moon has a pull on water ?

The phases of the moon are only light illusion. The full moon is always present whenever we see moon in the sky. Even in the new moon period, the full moon is present in the sky. How can then the phases of the moon influence the high and low tides ?

If moon exerts a strong pull on water to the surface which is closest to him, then how come the opposite side of the Earth also have this strong pull ? Does it not logically follows that the opposite side of the Earth which is farthest from the Moon has low tide ? How is it then that the opposite side is also having high tide ?

To Bob T
You have assumed that when it is moon in the sky, it is night time and the other side of the Earth is day time. Please check it out.

Answer 1

I'll attempt to answer the questions you raised but tides are complicated things...

High tides are bulges in the seas and oceans, each body of water has it's own tidal system. Even lakes and the water in your bath has a tide - it's just that it's imperceptibly small. There are therefore many tidal systems occuring simultaneously and many places around the globe experience high tides at more or less the same time. It's not quite as simple as high tide at one side of the earth and low tide at the other.

I'm assuming here that you're in the UK, apologises if not:

At about 8 O' clock this morning there was a high tide in Cornwall but at the same time it was low tide in Kent. But it's not as simple as this - there were other high tides in Yorkshire and the Hebrides but low tides in Northumberland and Merseyside (there were others). These bulges causing the high tides move around the coast. If we look at the south east there's a high tide today at about 2 o' clock in Dover, by 3 o'clock it will have moved to Ramsgate, 4 o'clock it's at Tilbury, 5 o'clock it's reached London Bridge etc.

It gets more complicated still because sometimes these bulges bump into each other. The Dorset coast is a good example of this - one high tide arrives from one direction and as it's receding another high tide arrives from the other direction. The result is that the sea comes in, partly goes out, partly comes back again, then goes out properly.

In short, high tides are like waves - there's lots of them and they're moving in complicated patterns and in different directions.

As for the role that the moon plays and the cuases of high tides...

There's several factors, the most noticable one is the gravitational effect of the moon, everything has gravity but the moon is very close to earth compared to the sun and other planets so it's effects are greter.

The moon rotates around the earth and together these, along with the other planets, rotate around the sun.

When the sun, the earth and the moon are together in a straight line is when the gravitational pull is at it's strongest - the moon takes about 29 days to go round the earth so this effect happens roughly each fortnight - once when the alignment is sun - moon - earth (new moon) and again when the alignment is sun - earth - moon (full moon).

The seas and oceans are so massive that the full gravitational effect of the moon takes a couple of days to peak and it's for this reason that the highest tides occur shortly after a full moon or new moon.

The sun also plays a part but to a lesser extent. The earth takes a year to go round the sun and the path it takes is an elipse - a slightly squashed circle, twice during the year we are closer to the sun and twice we are further away. The times we're nearest the sun are the autumnal and vernal equinoxes (the first days of spring and fall). Being closer to the sun means higher high-tides and lower low-tides and as a result the tides are at the highest and lowest at the start of spring and the start of fall.

When the full or new moon coincides with the vernal or autumnal equinoxes we get exceptionally high tides.

Other more localised factors are wind and air pressure. A strong driving wind will push the seas and oceans along in front of it (called a strom surge). An area of high pressure pushes down on the seas and oceans and displaces the water towards areas of low pressure - the low pressure areas effectively 'suck' the water upwards.

When several of these factors combine there can be catastrophic high tides leading to serious flooding and loss of lives. In 1953 a strom surge claimed over 2000 lives in England and the Netherlands and reclaimed over 2,000 square kilometres (800 square miles) of land.

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I fear that I haven't explained this very well - Answers would be so much better and easier if it allowed people to talk and use diagrams. E-mail me if the answer needs clarification.

Answer 2

"The Moon, being much nearer to the Earth than the Sun, is the principal cause of tides. When the Moon is directly over a given point on the surface of the Earth, it exerts a powerful pull on the water, which therefore rises above its normal level. Water covering the part of the Earth farthest from the Moon is also subject to this pull, so that another distinct dome of water is formed on the farther side of the Earth providing the basis for a second wave. The lunar wave crest directly beneath the Moon is called direct tide, and the crest on the side of the Earth diametrically opposite is called opposite tide. At both crests, the condition known as high water prevails, while along the circumference of the Earth perpendicular to the direct-opposite tidal axis, phases of low water occur."
Hope this helps!

Answer 3

The gravitational pull of the moon and the sun creates tides on the earth. While tides are most commonly associated with oceans and large bodies of water, gravity creates tides in the atmosphere and even the lithosphere (the surface of the earth). The atmospheric tidal bulge extends far into space but the tidal bulge of the lithosphere is limited to approximately 12 inches (30 cm) twice a day. The moon, which is approximately 240,000 miles (386,240 km) from the earth, exerts a greater influence on the tides then does the sun, which sits 93 million miles (150 million km) from the earth. The strength of the sun's gravity is 179 times that of the moon's but the moon is responsible for 56% of the earth's tidal energy while the sun claims responsibility for a mere 44% (due to the moon's proximity but the sun's much larger size).

Answer 4

Exceptionally High Or Low Tide

Answer 5

High and low tides come in phases of approximately slightly longer than six hours. High tide at a point today at noon means that tomorrow's midday high tide will be at around 1250pm. So the tides gradually move forward around the clock. In another few days that high tide will be around 4pm, and then 6pm.

This suggests that the high-low phases are spaced six hours across around the planet, and not 12 hours, so a high tide at one point means there is generally a low tide 6 hours east and 6 hours west.

There are local factors that influence tides, things like land masses, bays, bottoms, and so on. High tide at a given point does not mean the same high tide due north and due south of that line.

Answer 6

its only high tide when the moon is out in that time zone becouse the moons gravity pools the water up, causing the waters elevation to raise. So yes on the other side of the earth it would by daytime therefor low tide.

Answer 7

The tide always depends on the position of the moon, the moon is what causes the tide, so obviusly there cant be high tide in hollywood AND beging china

Answer 8

No please. When there is a high tide at one place due to gravitational or because of the planet position the just opposite place also will be high tide.