A flux transfer event (FTE) occurs when a magnetic portal opens in the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior Dynamo ...

through which high-energy particles flow from the Sun. This connection, while previously thought to be permanent, has been found to be brief and very dynamic. The

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

's four Cluster spacecraft and

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

's five THEMIS probes have flown through and surrounded these FTEs, measuring their dimensions and identifying the particles that are transferred between the magnetic fields.

Formation

According to NASA, Earth's magnetosphere and the Sun's magnetic field are constantly pressed against one another on the dayside of Earth. Approximately every eight minutes, these fields briefly merge, forming a temporary "portal" between the Earth and the Sun through which high-energy particles such as

solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

can flow. The portal takes the shape of a magnetic cylinder about the width of Earth. Current observations place the portal at up to 4 times the size of Earth.

Simulations

According to NASA, since Cluster and THEMIS have directly sampled FTEs, scientists can simulate FTEs on computers to predict how they might behave. Jimmy Raeder of the

University of New Hampshire The University of New Hampshire (UNH) is a Public university, public Land-grant university, land-grant research university with its main campus in Durham, New Hampshire, United States. It was founded and incorporated in 1866 as a land grant coll ...

told his colleagues simulations show that the cylindrical portals tend to form above Earth's

equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

and then roll over Earth's winter pole. In December, FTEs roll over the

North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...

; in July they roll over the

South Pole The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is the point in the Southern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True South Pole to distinguish ...

Flux transfer events beyond Earth

Magnetic fields similar to Earth's are common throughout known space and many undergo similar flux transfer events. During its second flyby of the planet on October 6, 2008, the NASA probe ''

MESSENGER Messenger, Messengers, The Messenger or The Messengers may refer to: People * Courier, a person or company that delivers messages, packages, or mail * Messenger (surname) * Bicycle messenger, a bicyclist who transports packages through cities * M ...

'' discovered that Mercury’s magnetic field shows a magnetic reconnection rate ten times higher than Earth's. Mercury's proximity to the Sun only accounts for about a third of the reconnection rate observed by ''MESSENGER'' and the cause of this discrepancy is not currently known. Most recently, it has been found that the same phenomenon, also known as a 'magnetic rope', can be observed at

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

. The findings prove that at times Saturn "behaves and interacts with the Sun in much the same way as Earth".

References

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