Why does the present shapes of the continents fit perfectly into one supercontinent

OverLord2011 [107]

Answer: The Earth's continents are in constant motion. On at least three occasions, they have all collided to form one giant continent. If history is a guide, the current continents will coalesce once again to form another supercontinent. And a study in Nature now shows how that could come about.

You can think of continents as giant puzzle pieces shuffling around the Earth. When they drift apart, mighty oceans form. When they come together, oceans disappear. And it's all because continents sit on moving plates of the Earth's crust.

Then, Now And Future

A new model of continental drift predicts that the next supercontinent could form near the North Pole — in another 100 million years or so.

Two of the previous supercontinents, which formed 200 million years ago (Pangaea) and 800 million years ago (Rodinia).

Mitchell, et. al./Nature

The Americas and Asia may fuse together to form a new supercontinent, "Amasia."

Mitchell, et. al./Nature

"Continents on these plates typically move, I would say, at the rate your fingernails grow," says Ross Mitchell, a graduate student at Yale University. That may seem slow, but it adds up over hundreds of millions of years.

Look at an atlas and you can imagine how Africa and South America, for example, once nestled together.

"Rewind the tape and bring all the continents back into their jigsaw arrangement, you have this vast landmass of all the Earth's continental blocks together," Mitchell says.

Last time all the landmass clumped up, it formed a supercontinent called Pangaea. The dinosaurs walked there. But Pangaea wasn't the first.

"There had been three, possibly a debated fourth supercontinent through the billions of years," Mitchell says.

He has been studying that deep history by looking at tiny magnets buried in rock around the world. Those magnets pointed north when they were locked into the rock. Sample those magnets in layers of rock laid down over millions of years, and you can tell the story of how those continents have moved.

And naturally, that led Mitchell to wonder what the next supercontinent will look like.

There have been two leading ideas. One is that the continents will collapse together again at the site of the last supercontinent, centered on Africa. That would squeeze the Atlantic Ocean shut. The other idea is that the Atlantic would keep growing and growing.

8 0

3 years ago

What has uekaryotik cells liver, virus, oak, lactobacillus?

padilas [110]

Eukaryotic cells have chromosomes, a membrane-bound nucleus, and membrane-bound organelles, practically any living thing. Eukaryotic cells are also considered animal cells.

It could be both liver and oak.
It could also just be liver if it specifies eukaryotic animal cells.

4 0

4 years ago

An allergic reaction characterized by the constriction of the bronchial tubes is known as

maxonik [38]

Answer: Asthma

Asthma is an allergic reaction characterized by the constriction of the bronchial tubes. Asthma (AZ-ma) is a chronic (long-term) lung disease that is characterized by the constriction of the bronchial tubes or airways. It causes chest tightness, shortness of breath, whistling sound when you breathe, and coughing.

8 0

4 years ago

Which enzyme is used specifically for RNA transcription from dna in

Vadim26 [7]

First, pre-messenger RNA is formed, with the involvement of RNA polymerase enzymes.

3 0

4 years ago

Describe dwarf planets and their orbits in the solar system

WITCHER [35]

Dwarf Planets of Our Solar System (Infographic) Pluto was demoted to dwarf planet status in 2006, joining Eris, Haumea, Makemake and Ceres. ...

Pluto, discovered in 1930, orbits the sun at an average of 39.5 times the Earth's distance. Its diameter is 1,430 miles (2,302 km)

Dwarf planets are worlds that are too small to be considered full-fledged planets, but too large to fall into smaller categories.

In recent years, there's been a lot of hubbub about Pluto losing its status as one of the planets of the solar system. Pluto is no longer considered the ninth planet in the series of major planetary objects, but instead is now just one of the many so-called "dwarf planets." The debate started anew after the New Horizons mission passed by Pluto in 2015, revealing a world of surprising geological complexity. As of 2017, delegates from the mission are trying to get Pluto's planethood status back.

Astronomers estimate that there could be as many as 200 dwarf planets in the solar system and the Kuiper Belt. But the differences between planets and dwarf planets may not be obvious at first.

Dwarf planets of the solar system

The International Astronomical Union defines a planet as being in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects. This last criterion is the point at which planets and dwarf planets differ. A planet's gravity either attracts or pushes away the smaller bodies that would otherwise intersect its orbit; the gravity of a dwarf planet is not sufficient to make this happen. [Meet the Dwarf Planets of the Solar System]

Meet the dwarf planets of our solar system, Pluto Eris, Haumea, Makemake and Ceres.Credit: Karl Tate, SPACE.com contributor

As of 2014, the IAU recognizes five named dwarf planets: Ceres, Pluto, Eris, Haumea, and Makemake. But those aren't the only ones. Other solar system bodies that are possibly dwarf planets include Sedna and Quaoar, small worlds far beyond Pluto's orbit, and 2012 VP113, an object that is thought to have one of the most distant orbits found beyond the known edge of our solar system. The object DeeDee could also be a dwarf planet, according to observations made in 2017. According to NASA, scientists think that there may be more than a hundred dwarf planets awaiting discovery.

However, the debate over the status of dwarf planets, particularly Pluto, remains a hot topic. The primary concern stems from the requirement for a planet to clear out its local neighborhood.

"In no other branch of science am I familiar with something that absurd," New Horizons principle investigator Alan Stern told Space.com in 2011. "A river is a river, independent of whether there are other rivers nearby. In science, we call things what they are based on their attributes, not what they're next to."

Is a dwarf planet a separate entity from a planet, or simply another classification? The question may not be settled in the near future.

6 0

4 years ago