- 3947 - BIG BANG THEORY - how it all got started? The Sun and the Earth formed a solar system. The Milky Way Galaxy is full of “suns”. And we have discovered at least 5,000 other planets around some of these stars. We know there are billions of galaxies in the Universe. How did this all come to be?
------------ 3947 - BIG BANG THEORY - how it all got started?
- The Big
Bang Theory is the leading explanation for how the universe began. Simply put,
it says the universe as we know it started with an infinitely hot and dense
single point that inflated and stretched.
First at unimaginable speeds, and then at a more measurable rate over
the next 13,700,000,000 years to the still-expanding cosmos that we know today.
-
- Existing
technology doesn't yet allow astronomers to literally peer back at the
universe's birth, much of what we understand about the Big Bang comes from
mathematical formulas and models. Astronomers can, however, see the
"echo" of the expansion through a phenomenon known as the “cosmic
microwave background”.
-
- Around 13.7
billion years ago, everything in the entire universe was condensed in an
infinitesimally small singularity, a point of infinite denseness and heat.
-
- Suddenly, an explosive
expansion began, ballooning our universe outwards faster than the speed of
light. This was a period of “cosmic inflation” that lasted fractions of a
second, about 10^-32 of a second.
-
- When cosmic
inflation came to a sudden and still-mysterious end, the more classic
descriptions of the Big Bang took hold. A flood of matter and radiation, known
as "reheating," began populating our universe with the stuff we know
today: particles, atoms, the stuff that would become stars and galaxies and so
on.
-
- This all
happened within just the first second after the universe began, when the
temperature of everything was still insanely hot, at about 10 billion degrees
Fahrenheit. The cosmos now contained a
vast array of fundamental particles such as neutrons, electrons and protons
which are the raw materials that would become the building blocks for
everything that exists today.
-
- This early
"soup" would have been impossible to actually see because it couldn't
hold visible light. mThe free electrons would have caused light (photons) to
scatter the way sunlight scatters from the water droplets in clouds. Over time
these free electrons met up with nuclei and created neutral atoms or atoms with
equal positive and negative electric charges.
-
- This
allowed light to finally shine through, about 380,000 years after the Big
Bang. Sometimes called the
"afterglow" of the Big Bang, this light is more properly known as the
cosmic microwave background (CMB). It was first predicted by Ralph Alpher and
other scientists in 1948 but was found only by accident almost 20 years later.
-
- This
accidental discovery happened when Arno Penzias and Robert Wilson, both of Bell
Telephone Laboratories in New Jersey, were building a radio receiver in 1965
and picked up higher-than-expected temperatures. At first, they thought the
anomaly was due to pigeons trying to roost inside the antenna and their waste,
but they cleaned up the mess and killed the pigeons and the anomaly persisted.
-
-
Simultaneously, a Princeton University team led by Robert Dicke was
trying to find evidence of the CMB and realized that Penzias and Wilson had
stumbled upon it with their strange observations. The two groups each published
papers in the Astrophysical Journal in 1965.
-
- Researchers
investigated the split between matter and antimatter. In the study they
proposed that the imbalance in the amount of matter and antimatter in the
universe is related to the universe's vast quantities of dark matter, an
unknown substance that exerts influence over gravity and yet doesn't interact
with light. They suggested that in the crucial moments immediately after the
Big Bang, the universe may have been pushed to make more matter than its
inverse, antimatter, which then could have led to the formation of dark matter.
-
- The CMB has
been observed by many researchers now and with many spacecraft missions. One of
the most famous space-faring missions to do so was NASA's Cosmic Background
Explorer (COBE) satellite, which mapped the sky in the 1990s.
-
- Several
other missions have followed in COBE's footsteps, such as the BOOMERanG
experiment (Balloon Observations of Millimetric Extragalactic Radiation and
Geophysics), NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and the
European Space Agency's Planck satellite.
-
- Planck's
observations mapped the CMB in unprecedented detail and revealed that the
universe was older than previously thought: 13.82 billion years old, rather
than 13.7 billion years old.
-
- The maps
give rise to new mysteries, however, such as why the Southern Hemisphere
appears slightly redder (warmer) than the Northern Hemisphere. The Big Bang
Theory says that the CMB would be mostly the same, no matter where you look.
-
- Examining
the CMB also gives astronomers clues as to the composition of the universe.
Researchers think most of the cosmos is made up of matter and energy that
cannot be "sensed" with our conventional instruments, leading to the
names "dark matter" and "dark energy."
-
- It is
thought that “only 5% of the universe” is made up of matter such as planets,
stars and galaxies, and us.
-
- In the
first second after the universe was born, our cosmos ballooned faster than the
speed of light. (That does not violate Albert Einstein's speed limit. He once
said that light speed is the fastest anything can travel within the universe,
but that statement did not apply to the inflation of the universe itself.)
-
- As the
universe expanded, it created the CMB and a similar "background
noise" made up of gravitational waves that, like the CMB, were a sort of
static, detectable from all parts of the sky. Those gravitational waves,
according to the LIGO Scientific Collaboration produced a theorized
barely-detectable polarization, one type of which is called "B-modes."
-
- These waves,
which are not B-modes from the birth of the universe but rather from more
recent collisions of black holes, have been detected multiple times by the
Laser Interferometer Gravitational-Wave Observatory (LIGO). As LIGO becomes more sensitive, it is
anticipated that discovering black hole-related gravitational waves will be a
fairly frequent event.
-
- Although the
Big Bang is often described as an "explosion", that's a misleading
image. In an explosion, fragments are flung out from a central point into a
pre-existing space. If you were at the central point, you'd see all the
fragments moving away from you at roughly the same speed.
-
- But the Big
Bang wasn't like that. It was an expansion of space itself. Which is a concept that comes out of
Einstein's equations of general relativity but has no counterpart in the
classical physics of everyday life.
-
- It means
that all the distances in the universe are stretching out at the same rate. Any
two galaxies separated by distance X are receding from each other at the same
speed, while a galaxy at distance 2X recedes at twice that speed.
-
- The universe
is not only expanding, but expanding faster. This means that with time, nobody
will be able to spot other galaxies from Earth or any other vantage point
within our galaxy.
-
- Eventually,
a distant galaxy will reach the speed of light. What that means is that even
light won't be able to bridge the gap that's being opened between that galaxy
and us. There's no way for extraterrestrials on that galaxy to communicate with
us, to send any signals that will reach us, once their galaxy is moving faster
than light relative to us.
-
- While we
can understand how the universe we see came to be, it's possible that the Big
Bang was not the first inflationary period the universe experienced. Some
scientists believe we live in a cosmos that goes through regular cycles of
inflation and deflation, and that we just happen to be living in one of these
phases
-
- A telescope is almost like a time machine,
allowing us to peer back into the distant past. With the aid of the Hubble
space telescope, NASA has shown us galaxies as they were many billions of years
ago, and, Hubble's successor, the James
Webb Space Telescope, has the ability to look even deeper into the past.
-
- NASA hopes
it will see all the way back to when the first galaxies formed, nearly 13.6
billion years ago. And unlike Hubble, which sees mainly in the visible
waveband, JWST is an infrared telescope which is a big advantage when looking
at very distant galaxies.
-
- The
expansion of the universe means that waves emitted from them are stretched out,
so light that was emitted at visible wavelengths actually reaches us in the
infrared.
-
April 6, 2023 BIG BANG
THEORY - how it all got started? 3947
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