බටහිර විද්යාවේ ඇසින් ශූන්යය
බටහිර බොහෝ දෙනාට ඊනියා පැවැත්මක් අවශ්ය වෙනවා. ඇතිවෙමින් නැතිවෙමින් ප්රවාහයට ඔවුන් පැමිණ ඇතත් එය යථාර්ථයක් ලෙස ගැනීමට ඔවුන් පෙළඹෙනවා. නාගර්ජුනපාදයන්ගේ ශූන්යතාව යන්න ද ප්රශ්න ඇති කරන බව මතක් වෙනවා.
මෙහි ඇත්තේ ශූන්ය මුද්රාව. එය මෙයට ගැලපෙනවා ද යන්න ප්රශ්නයක්.
“Nothing” doesn’t exist. Instead, there is “quantum foam”
When you combine the Uncertainty Principle with Einstein's
famous equation, you get a mind-blowing result: Particles can come from
nothing.
- The concept of "nothing" has been debated
for millennia, by both scientists and philosophers.
- Even if you took an empty container devoid of all
matter and cooled it to absolute zero, there is still
"something" in the container.
- That something is called quantum foam, and it
represents particles blinking into and out of existence.
What is nothing? This is a question that has bothered
philosophers as far back as the ancient Greeks, where they debated the nature
of the void. They had long discussions trying to determine whether nothing is
something.
While the philosophical facets of this question pose
some interest, the question is also one that the scientific community has
addressed. (Big Think’s Dr. Ethan Siegel has an article describing the four definitions of
“nothing.”)
It’s
nothing, really
What would happen if scientists took a container and
removed all the air out of it, creating an ideal vacuum that was entirely
devoid of matter? The removal of matter would mean that energy would remain.
Much in the same way that the energy from the Sun can cross to the Earth
through empty space, heat from outside the container would radiate into the
container. Thus, the container wouldn’t be truly empty.
However, what if scientists also cooled the container to
the lowest possible temperature (absolute zero), so it radiated no energy at
all? Furthermore, suppose that scientists shielded the container so no outside
energy or radiation could penetrate it. Then there would be absolutely nothing
inside the container, right?
That’s where things become counterintuitive. It turns
out that nothing isn’t nothing.
The
nature of “nothing”
The laws of quantum mechanics are confusing, predicting
that particles are also waves and that cats are simultaneously alive and dead.
However, one of the most confusing of all quantum principles is called
the Heisenberg Uncertainty Principle, which is commonly
explained as saying that you cannot simultaneously perfectly measure the
location and movement of a subatomic particle. While that is a good
representation of the principle, it also says that you cannot measure the
energy of anything perfectly and that the shorter the time you measure, the worse
your measurement is. Taken to the extreme, if you try to make a measurement in
near-zero time, your measurement will be infinitely imprecise.
There is no evidence for a Universe before theBig Bang
These quantum principles have mind-bending consequences
for anyone trying to understand the nature of nothing. For example, if you try
to measure the amount of energy at a location — even if that energy is supposed
to be nothing — you still cannot measure zero precisely. Sometimes, when you
make the measurement, the expected zero turns out to be non-zero. And this
isn’t just a measurement problem; it’s a feature of reality. For short periods
of time, zero is not always zero.
When you combine this bizarre fact (that zero expected
energy can be non-zero, if you examine a short enough time period) with
Einstein’s famous equation E = mc2, there is an
even more bizarre consequence. Einstein’s equation says that energy is matter
and vice versa. Combined with quantum theory, this means that in a location
that is supposedly entirely empty and devoid of energy, space can briefly
fluctuate to non-zero energy — and that temporary energy can make matter (and
antimatter) particles.
Quantum
foam
Thus, at the tiny quantum level, empty space isn’t
empty. It’s actually a vibrant place, with tiny subatomic particles appearing
and disappearing in wanton abandon. This appearance and disappearance has some
superficial resemblance to the effervescent behavior of the foam on the top of
a freshly poured beer, with bubbles appearing and disappearing — hence the term
“quantum foam.”
The quantum foam isn’t just theoretical. It is quite
real. One demonstration of this is when researchers measure the magnetic
properties of subatomic particles like electrons. If the quantum foam isn’t
real, electrons should be magnets with a certain strength. However, when
measurements are made, it turns out that the magnetic strength of electrons is
slightly higher (by about 0.1%). When the effect due to quantum foam is taken
into account, theory and measurement agree perfectly — to twelve digits of
accuracy.
Another demonstration of the quantum foam comes courtesy
of the Casimir Effect, named after Dutch physicist Hendrik Casimir. The effect
goes something like this: Take two metal plates and put them very near one
another in a perfect vacuum, separated by a tiny fraction of a millimeter. If
the quantum foam idea is right, then the vacuum surrounding the plates is
filled with an unseen flurry of subatomic particles blinking into and out of
existence.
These particles have a range of energies, with the most
likely energy being very small, but occasionally higher energies appear. This
is where more familiar quantum effects come into play because classical quantum
theory says that particles are both particles and waves. And waves have
wavelengths.
Outside the tiny gap, all waves can fit without
restriction. However, inside the gap, only waves that are shorter than the gap
can exist. Long waves simply cannot fit. Thus, outside the gap, there are waves
of all wavelengths, while inside the gap there are only short wavelengths. This
basically means that there are more kinds of particles outside than inside, and
the effect is that there is a net pressure inward. Thus, if the quantum foam is
real, the plates will be pushed together.
Scientists made several measurements of the Casimir effect, however it was in 2001 when the effect was conclusively demonstrated using the geometry I have described here. The pressure due to the quantum foam causes the plates to move. The quantum foam is rea
l. Nothing is something after all.
