- 4378 - STRONGEST MAGNET? - Scientists just created the strongest magnetic force in the universe. You may never have heard of “magnetars”, but they are an exotic type of neutron star whose magnetic field is around a trillion times stronger than the Earth’s.
----------------------------------------- 4378 - STRONGEST MAGNET?
- If you were to get any closer to a magnetar
than about 600 miles away, your body would be totally destroyed. Its unimaginably powerful field would tear
electrons away from your atoms, converting you into a cloud of monatomic ions,
single atoms without electrons.
-
- And yet, scientists have just discovered
that there could be zones, right here on our beloved planet, where flashes of
magnetism burst with strengths that make magnetars look positively feeble.
-
- How on Earth is this possible? After smashing together nuclei of various
heavy ions in this massive particle accelerator, physicists at the Brookhaven
lab found evidence of record-breaking magnetic fields.
-
- By measuring the motion of even smaller
particles. “Quarks” (the building
blocks of all visible matter in the universe) and gluons (the “glue” that binds
quarks together to form the likes of protons and neutrons) scientists hope to
gain new insights into the deep inner workings of atoms.
-
- Alongside these two elementary particles,
there exist antiquarks. For every
“flavor” of quark, there is an antiquark, which has the same mass and energy at
rest as its corresponding quark, but the opposite charge and quantum number.
-
- The lifetime of quarks and antiquarks
inside nuclear particles is brief. But the more we can grasp how they move and
interact, the better experts will understand how matter, and by extension, the whole universe is
constructed.
-
- In order to map the activity of these
fundamental particles, physicists require a super-strong magnetic field. To create this, the team at the Brookhaven
lab used the RHIC to create
off-center collisions of heavy atomic nuclei, in this case, gold.
-
- The powerful magnetic field generated by
this process induced an electrical current in the quarks and gluons that were
“set free” from the protons and neutrons that separated during the smashups.
-
- The result is that experts now created a new
way of studying the electrical conductivity of this “quark-gluon plasma”
(QGP). This is a state where quarks and
gluons are liberated from the colliding protons and neutrons that will help
improve our grasp of these fundamental building blocks of life.
-
- This is the first measurement of how the
magnetic field interacts with the quark-gluon plasma. Measuring the impact of these off-center
collisions on the particles streaming out, is the only way of providing direct
evidence that these powerful magnetic fields exist.
-
- Experts had long believed that such
off-center smashes would generate powerful magnetic fields, however, for years
it was impossible to prove. This is
because things happen very quickly in heavy ion collisions. It disappears in ten millionths of a
billionth of a billionth of a second.
-
- Yet, however fleeting this field may be, it
sure is strong. This is because some of the non-colliding positively charged
protons and neutral neutrons that make up the nuclei are sent spiraling off,
resulting in an eddy of magnetism so powerful, they deliver more gauss (the
unit of magnetic induction) than a neutron star.
-
- Those fast-moving positive charges should
generate a very strong magnetic field, predicted to be 10^18 gauss. By way of comparison, neutron stars, the densest objects in the
universe, have fields measuring around 10^14 gauss, while fridge magnets
produce a field of about 100 gauss, and Earth’s protective magnetic field is a
mere 0.5 gauss.
-
- That means that the magnetic field created
by the off-center heavy ion collisions is probably the strongest in our
universe. Now that the scientists have
evidence that magnetic fields induce an electromagnetic field in the QGP, they
can investigate the QGP’s conductivity.
-
- The extent to which the particles are
deflected relates directly to the strength of the electromagnetic field and the
conductivity in the QGP, and no one has measured the conductivity of QGP
before.
-
- Speaking of magnetic fields every so often,
Earth's magnetic poles completely flip. What causes this to happen? And how do
these reversals affect life on Earth?
-
- Earth, our rocky, watery oasis in the
universe is the ideal place for life to flourish for a number of reasons. We sit at just the right distance from our
home star for liquid water to exist on the planet's surface. The gravitational
pull of other large planets helps protect us from apocalyptic collisions with
wandering meteorites. And the planet's magnetic field encircles Earth with a
protective barrier that shields us from charged particles hurtling through
space.
-
- Earth's magnetic field is generated by the
complex flow of molten metallic material in the outer core of the planet. The
flow of this material is affected both by the rotation of Earth and the
presence of a solid iron core, which results in a dipolar magnetic field where
the axis roughly aligns with the rotational axis of the planet.
-
- Hidden in the chemical composition of
ancient rocks are clues that Earth's magnetic field is a dynamic, shifting
phenomena. Cooling magma rich in iron minerals is pulled into alignment with
Earth's magnetic field, similar to how a needle is pulled to point towards
north on a compass. The study of ancient geomagnetic fields recorded in rocks
is the subject of a discipline known as "paleomagnetism."
-
- Paleomagnetic research has provided
scientists with the knowledge that Earth's magnetic field has shifted and even
reversed in polarity many times in the geological past. But why?What causes the
magnetic poles to flip?
-
- Earth's magnetic field varies at very short
timescales and extremely long ones, ranging from milliseconds to millions of
years. The interaction of the magnetic field with charged particles in space
can alter it at short timescales, while perturbations in the magnetic field at
longer timescales are caused by internal processes unfolding in the outer
liquid core of the Earth.
-
- Fluctuations in the magnetic field caused
by the movement of metallic material in the outer core have brought about full
reversals of the magnetic field's polarity in Earth's past. Paleomagnetic
studies which have studied previous states of the magnetic field have shown
there are two possible states of polarity.
The current 'normal' state, where the lines of force of the field enter
towards the center of the Earth in the northern hemisphere and exit towards the
outside of the Earth in the southern hemisphere. The inverse, or 'reverse'
polarity is also equally as probable and stable.
-
- Paleomagnetic studies have shown that
polarity reversals of Earth's magnetic field are not periodic and cannot be
predicted. This is largely because of the behavior of the mechanisms that are
responsible for it.
-
- The flow of the metallic fluid (mostly
molten iron) in the outer core of the Earth is chaotic and turbulent. Polarity
reversals occur during periods of low geomagnetic field intensity, during which
the intensity of the dipolar component drastically decreases, and the structure
of the field is unstable.
-
- The transitory period of polarity reversal
appears as a geologically instantaneous, below the geological resolution, with
a duration spanning up to a few thousand years. How do magnetic pole reversals
affect life on Earth?
-
- When the magnetic field is prone to
flipping, it is in a state of reduced intensity, resulting in a greater
exposure of Earth's atmosphere to solar wind and cosmic rays in the form of
charged particles. A recent study showed that during the “Laschamps excursion”,
a recent period of low magnetic field intensity which occurred only 41,000
years ago, the global cosmic ray flux reaching the Earth's atmosphere was up to
three times higher than today's value.
-
- There is no significant evidence of a
correlation between mass extinctions of life on Earth and geomagnetic polarity
reversals. However, linking rates of species extinction and speciation with
periods of low magnetic field intensity is hindered by uncertainties in the
known timescale of these magnetic 'flips'.
-
- Magnetic reversals happen frequently on
geological timescales (several hundred times in the past 160 million years),
while recorded mass extinction events occur every hundred million years or so
(much less frequently).
-
- In terms of human civilization, it is not
the shifting of the magnetic poles that is directly concerning, but the
resulting period of reduced geomagnetic field intensity. Society is growing
increasingly reliant on technology, and the effects of a reduced magnetic field
intensity should be seriously considered by governments and international
organizations.
-
- The risks to which our planet and
civilization is exposed could have significant impacts on civil society, how we
do commerce, security, communications, power infrastructure, satellites and the
lives of people in low Earth orbit. Unfortunately, the sporadic nature of
magnetic variations and reversals means we cannot predict when exactly this
will happen, all we know is that it will happen.
-
-
March 7, 2024 STRONGEST MAGNET? 4378
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--------------------- --- Thursday, March 7, 2024
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