What happens once seems to happen twice.
■Key points of this article that can be understood in 3 lines
- UT Austin researchers suggest a “dark big bang” happened after the initial big bang. They believe dark matter was formed during this event.
- It is possible that the laws controlling space bodies were affected by the second big bang and dark matter formation. Scientists may be able to prove this by studying gravitational waves.
- The idea implies that the universe had a complicated beginning. Many changes happened, and a possible shadow explosion was vital to its development.
The University of Texas at Austin (UT Austin) did research. They found that a “dark big bang” might have happened shortly after the first big bang. This second big bang made dark matter.
The study shows that the dark Big Bang made dark matter. It is much heavier than normal matter particles. It created the basis of physical laws that control stars’ movement around galaxies from the shadows.
Scientists found evidence of the first Big Bang by studying cosmic background radiation. They believe they can prove the existence of a dark big bang by analyzing gravitational waves. These waves are present in the background of the universe.
Learning about the second Big Bang (dark Big Bang) may help us understand how the universe was born.
I will first explain the question “What is the Big Bang?” using phase transitions. Then I will introduce how the dark Big Bang theory came to be.
The research’s information is on the preprint server “arXiv” named “Dark Matter and Gravity Waves from a Dark Big Bang.” The study has not yet been published in a peer-reviewed journal as of November 14, 2023.
“What’s the Big Bang?” This article explains it using phase transition.
The big bang was not the beginning of the universe
Many people think that the universe began with something called the Big Bang. This created a big explosion which made everything in the universe.
It’s often called that in old kids’ science magazines.
However, the Big Bang is currently not considered to be the beginning of the universe.
The universe’s basic parts were small and contracted. They grew quickly in a process called inflation. Then they cooled down and heated up again.
As kids, we believed in Big Bang. However, it was just a reheat process!
Since our universe was born,
The universe started as an ultra-hot and super-dense point. Then, inflation caused rapid expansion and cooling. After this, there was a reheating process (Big Bang), which led to the birth of elementary particles. The Higgs boson’s properties changed, leading to the creation of atoms. Finally, stars were born, resulting in our current universe.
The situation was changing rapidly.
When things in the universe change a lot, it’s called a “phase transition.” This kind of change affects everything around it. It changes how objects behave, how space and time work, and even how forces work.
And it’s not just the temperature and size of the universe that has changed.
In the past, all four natural forces (gravity, electric force, nuclear force) were joined into one.
During a phase change in the universe, the forces became different and took on their current shape.
The forces branching out is similar to a tree growing and dividing into multiple branches.
All branches come from the same trunk. As they grow, they go different ways.
When new branches grew, forces and laws changed in the universe.
(The Higgs particle changed and attached to tiny particles, producing “mass”. This caused the particles’ speed to decrease, leading to the formation of an atomic structure.)
The Big Bang was one of many transitions.
Scientists are unsure what caused the inflation, but one theory is a special “quantum field” that covers the universe.
Quantum fields are essential parts of the universe. They are present everywhere and provide the basis for matter and energy to exist.
When there is inflation, the field holding up the universe gets shaky. Due to this, scientists think that the universe grows quickly.
Imagine the universe is like an aquarium filled with water. Now, if this water suddenly boils and becomes steam, that’s what we mean.
After inflation ends, a field shrinks and gets hot. This releases lots of particles and radiation from nowhere. These things become stars and the building blocks of our bodies.
Think of sugar dissolving in water. With time, the water disappears, and sugar forms crystals again.
This is a phenomenon known as the “Big Bang.”
After the Big Bang, tiny things formed atoms. This happened in about 12 minutes. Then, stars and galaxies started to form. This took hundreds of millions of years.
Particles come from space and also emerge when particle accelerators produce energy. This is true for the current universe because it was true in the past.
We live in an expanding universe. We exist in the middle or at the foot of the Big Bang. Therefore, this is our reality.
This paragraph discusses “ordinary matter,” including particles and atoms.
There is “dark matter” in the universe. It’s bigger than normal matter.
Dark matter was created in the second big bang
What exactly is dark matter?
What exactly is dark matter? / Credit: XMASS
Dark matter is matter that cannot be seen directly.
Dark matter can’t be seen because it doesn’t react to light. It is also unable to emit, absorb or reflect light.
If we get hit by a dark matter fist of 10 kg, we won’t feel anything. This is because our bodies are made of normal matter, and the two don’t interact.
Scientists do not know what dark matter is, but they know it has gravity. We have seen proof that it exists.
The best example of this is seen in the movement of stars around the galaxy.
The stars in the galaxy obey Newton’s laws of motion. Thus, stars located in the center spin quickly, while those at the edges spin slowly.
Mercury is a planet in the solar system that moves quickly. However, Neptune and Pluto move at a slower pace.
When we look at how fast stars spin in the galaxy, we see that center and outer parts spin at same speed.
(*In other words, the outside was moving faster than expected.)
Based on Newton’s laws, we found out that there is “something” around the galaxy which is emitting gravity. This “something” is about 10 times more than visible matter.
This invisible something is called “dark matter.”
Existing theories suggest that so-called dark matter was also created by the Big Bang.
If we compare the universe before the Big Bang to water with sugar and salt dissolved in it, the Big Bang caused a phase transition. It’s like how water vaporizes and forms crystals. This event caused sugar crystals to form and both salt crystals to appear.
The dark big bang that produces dark matter
Physicists have made detectors to find dark matter since the theory was proposed 40 years ago.
Many detectors are made based on the idea that dark matter is a particle called WIMP.
(*If the existence of WIMP is confirmed, it will reveal part of the true nature of dark matter.)
WIMP, one of the four fundamental forces in nature, is affected by weaker nuclear force and gravity.
If WIMP is real, it must interact with the nucleus.
As an illustration, a tiny boat on the sea is affected by waves (gravity) and wind (weak nuclear force). Similarly, WIMPs are believed to react to these forces.
But so far, WIMP has not been discovered.
Scientists think that dark matter has not been found because it does not interact with the weak nuclear force. It is like a boat moved by waves (gravity) but not affected by wind (weak nuclear force). This shows that it might have unique properties.
In that case, gravity is the only connection to normal matter.
Theoretically, if gravity is the only link, dark matter can form outside the first Big Bang. This means it can have its own birth path.
If someone has an invisible sibling, it’s like having a twin born on the same day or a regular sibling born at another time.
Scientists made a new theory about how dark matter was formed. This is based on what they already observed.
Then, it turns out that if a “second big bang due to dark matter” occurs a few weeks after the regular big bang, the results will most closely match the actual observational data.
Scientists have done calculations. They found something interesting. It’s about dark big bang particles. These particles are big and dark. They also weigh more than protons, a lot more. 10 trillion times more!
(*Researchers named these giant particles “darkzillas” after the Japanese Godzilla.)
A second big bang may sound suspicious.
Existing theories on the beginning of the universe such as ultra-high temperature, high density point, inflation, and the Big Bang were considered nonsense.
The Big Bang got its name from people who didn’t believe it was possible and wanted to make fun of it.
(*The name was meant to make fun of it, as in Japanese it means “daibakuhatsu (lol)”)
But in the 1960s, clear evidence was discovered.
Cosmic microbackground radiation waves are emitted from everywhere in space. They are a result of the Big Bang which caused the universe to expand.
This is when humans saw a signal from space and understood the beginning of the universe.
The word “Big Bang” was originally a mean name but became an important theory.
Is there evidence that the dark big bang causes a reversal like the cosmic background radiation?
The dark big bang proof is in the waves that move space.
According to researchers, the early universe experienced a sudden change in the state of matter called phase transition. This process was caused by something called the “dark big bang”. As a result, ripples in space and time were created which are known as gravitational waves.
Gravitational waves were found in 2016. They are like ripples from a stone thrown into water.
It has been found out where the gravitational force came from. It is believed to be due to the collision of high-density objects like black holes and neutron stars.
Scientists believe that there’s a kind of gravitational wave called “background hum.” It’s like the cosmic microwave background radiation (CMB).
(*“Background hum” refers to low-level, persistent gravitational wave signals that are always present in the background of the universe.)
Astronomers from NANOGrav will detect the “background hum of gravitational waves” in June 2021.
Congratulations to NANOGrav for detecting evidence that gravitational waves fill the cosmos.— NASA (@NASA) June 29, 2023
These ripples in the fabric of space happen when massive objects like black holes circle one another before colliding. The result brings us closer to understanding how galaxies evolve.… pic.twitter.com/AuXBgkZkb7
Researchers think the signal came from a black hole crash, or it may have come from an early universe change.
Researchers studied the hum of gravitational waves and found evidence of a second “dark big bang” caused by dark matter.
Scientists are trying to find gravitational waves better. They are working on it now. A laser interferometer space antenna will launch in 2037. This is from the European Space Agency.
Three spacecraft fly in formation to measure gravitational waves. They send a laser beam to each other. The laser beam measures the waves precisely.
The gravitational wave “hum” may have a directionality. This means it’s a ripple caused by a black hole or neutron star collision that happens in a particular direction.
If the hum of gravitational waves is detected from all directions, without any particular directionality, like cosmic background radiation, it suggests an unknown phase transition in the early universe. This would also be evidence of a large explosion that is different from radiation, known as a dark big bang.
In the future, we might accept the “Dark Big Bang” and “Second Big Bang” theories seriously. This is similar to how people used to deny the Big Bang but now accept it.