0
How do scientists know that the earths magnetic poles have reversed themselves many times during earths history?
Wiki User
∙ 8y ago
The answer lies in ocean basalts. As the sea floor slowly spreads, the igneous rock of which it is comprised cools and congeals, recording earth's current magnetic pole alignment. It turns out there are numerous parallel stripes encoded within ocean bedrock, indicating the strength and polarity of earth's magnetic field over the course of many millions of years. One trouble with this record is that once the sea floor reaches a continental plate margin it is subducted beneath the crustal rock and destroyed, so the record is only about a hundred million years old at most.
However, there is excellent agreement between the sea floor rock and volcanic rock deposited on earth's surface. We can date isotopes within that rock to compare the sea floor record with the record on land, and confirm the accuracy of the dating techniques. One fascinating find is known as the Jaramillo Creek event, a pole reversal from about 900,000 years ago.
Wiki User
∙ 8y ago
Wiki User
∙ 14y agoExamination of the mid-Atlantic ridge and the lave deposits left on the ocean floor has indicated that every few million years, the Earth's magnetic polarity seems to reverse.
Add your answer:
Earn +20 pts
What in the Earth's gravity makes a compass point north?
It has nothing to do with gravity. The core of the earth is magnetic and the earth's north pole is actually magnetic north... at least for a while. Geologists are telling us that the magnetic field is breaking down. There is evidence that the earth has done that a few times in it's history. Some have even claimed that it is actually the cause of global climate change.
do you think that scientists will ever run out of things to study?
No, the universe is infinite there will always be something to study as humans keep growing and rewriting history,
Was Apollo 11 a hoax?
Yes it was. Apollo 11 is the biggest lie in history, everyone who took part in it should be ashamed of themselves if they aren't already!
What happened before Einstein changed how scientists thought about the universe?
From the time of Aristotle people had thought it impossible for electromagnetic waves, including light, to travel through 'empty' space. They theorised the presence of a substance known as aether (or ether) as a medium, and in the years prior to Einstein's publication about special relativity several scientists wrestled with the difficulties inherent in making use of this concept. Please see the link for more of the history.
What are two scientist important to your understanding of astronomy?
The scientists who did the most to help us to understand motion are Isaac Newton (who devised the Laws of Motion) and Albert Einstein (who devised the theory of relativity).
What do earths magnetic stripes indicate about ocean crust?
reversed itself in the pastThe alternating magnetic orientation is caused by polar shifts or reversal, (not end of the world kinda stuff). When the rock is new and molten the grains are free to align themselves with the prevailing magnetic field, as the rock cools, the grains are frozen in time. As the sea floor expands outward (in the Atlantic), it is regularly striped with rock oriented in different directions. This indicates that the magnetic poles have reversed many times throughout the Earth's history.
What is the result of Magnetic reversals?
The north pole becomes the south pole and vice versa. Also any rocks cooling in the reversed field will trap the magnetic polarity prevalent at their time of cooling. This means we can can trace the history of past magnetic reversals.
How long ago did the earths magnetic field reverse itself?
The last time that Earth's magnetic field reversed itself was 780,000 years ago. See the related link for two timelines showing geomagnetic reversals in Earth's history.
What are pole reversals?
The direction of the Earth's magnetic field has reversed several times during its history. This causes the North magnetic pole to become a South magnetic pole and vice versa. We know this because of the direction of magnetism in the rocks on the ocean floor, which alternates in 'stripes' on either side of the mid-ocean ridges.
Do the earth's magnetic poles have reversed themselves?
Yes, in the history of Earth, it has happened a handful of times. When it switches we experience what we call a pole reversal. Right now Earth is currently in the process of a pole reversal (the South Pole is moving northwards).
Is earths magnetic field slowly reducing?
Scientists are still struggling on what are the sources of earth's magnetic field (EMF). The facts support the notion that the EMF has reversed its direction several times in earth's history. When the EMF reverses, the EMF intensity will be weakened. Some evidence supports that the EMF intensity is now peaking and is due for a complete reversal in thousands of years. So yes, the EMF will be weakening. What we should worry about is what effects do the sun's activities have upon the EMF in our lifetime. The solar winds can weaken the EMF too. Scientists are predicting major solar activities coming (check the related link). ======================
What evidence supports the idea that the earth's magnetic north and south pole have changed many times throughout earth's history?
nothing scientists made it up to stop global warming
Why is paleomagnetism important?
Paleomagnetism is an important tool used to unravel Earth's past movements of tectonic plates. By studying the magnetic fields left in rocks, scientists have learned how the continental and oceanic plates have moved in history.
What are two ways that scientists can study earths climates history?
What are two ways that's scientists can study earths climates history
How do scientists reconstruct history?
Studyisland answer: all of these
How do magnetic stripes show Earth's history of magnetic fields?
As you move away from an ocean ridge, the rocks get older.
What has the author Margaret W Rossiter written?
Margaret W. Rossiter has written: 'Women scientists in America' -- subject(s): Women in science, Women scientists, History 'Women scientists in America' -- subject(s): History, Women in science, Women scientists
