Introduction
The total amount of atoms and light in the universe is less than 5% of the total amount of matter. Dark matter and dark energy are invisible yet control the structure and evolution of the universe, and make up the rest. Dark matter accounts for most mass in galaxies and galaxy clusters, and it is responsible for how galaxies are arranged on a large scale. Meanwhile, the unexplained power driving the universe's fast expansion is known as dark energy. Some of the most significant issues facing modern astronomers are determining what these compounds are and how they act.
Our cosmos is held together by dark matter, which acts as an attracting force. Because dark matter interacts with gravity yet does not reflect, absorb, or emit light, this is the case. Dark energy is a repellent force — an anti-gravity — that propels the universe's ever-accelerating expansions.
Dark energy is the more powerful of the two, accounting for around 68 per cent of the total mass and energy of the particular universe. Dark matter accounts for 27% of all matter in the universe. The rest of the matter we see and interact with daily makes up only 5% of the total.
Dark Matter vs. Dark Energy
Dark matter attracts rather than repelling dark energy. Dark matter impacts individual galaxies, but dark energy has an impact only on the grand scale of the universe. There could be 100 billion galaxies in our universe, each with billions of stars, massive clouds of gas and dust, and possibly scads of planets, moons, and other things. From radio waves to X-rays, the stars release a vast amount of energy that travels at the speed of light across the universe. Everything we see is just the tip of the cosmic iceberg, accounting for only roughly 4% of the universe's total mass and energy.
Dark matter, which emits no visible energy but exerts a gravitational pull on all visible stuff in the cosmos, makes up around a quarter of the universe. Dark matter and dark energy are easily confused due to their names. Even though they are linked, their impacts are vastly different. Dark matter attracts, while dark energy repels. Dark energy drives matter outward, whereas dark matter pulls it inside. On the other hand, dark matter has an impact on individual galaxies and the entire universe, but dark energy is only seen at the grandest cosmic scale. Dark matter was found by astronomers while exploring the furthest reaches of our galaxy, the Milky Way.
Difference between Dark Matter and Dark Energy in Tabular Form
| Parameters Of Comparison | Dark Matter | Dark Energy |
| Definition | It’s a form of matter | It’s a form of energy |
| Distribution | It comprises 27% of the universe. | It comprises 68% of the universe. |
| Force | It's an attractive force. | It's a repulsive force. |
| Impact | It holds the galaxies intact | It accelerates the expansion of the universe |
| Existence | It exists in space only. | It exists both in space and time. |
What is Dark Matter?
If it weren't for the gravitational glue produced by enormous yet undetectable mass amounts, the universe would rip itself apart. Even considering all of the ordinary matter we can't see — such as exoplanets, galactic gas clouds, and black holes that don't radiate light — it's not enough to make up the difference. The enormous gravity of galaxy clusters bends light from further away objects, acting as a cosmic magnifying glass. Gravitational lensing is far too powerful to be created by ordinary stuff.
Gas filaments (seen in orange at right) connect galaxies spread across the sky. Only the presence of underlying dark matter concentrations may explain the structure of this vast cosmic web (blue). Temperature variations in the relic afterglow of the Big Bang cannot be explained by ordinary stuff. The cosmic microwave background (CMB) can be seen as microwaves throughout the sky.
Dark Matter: What Is It?
Wimps:
Weakly interacting massive particles, significantly heavier than protons and neutrons in atomic nuclei, are called wimps. Wimps would "sense" matter through gravity and the so-called weak force, which causes atoms to disintegrate radioactively.
Axions:
Is this a twofer? Physicists invented the axion to explain why neutrons do not spin in electric fields. The particle's other characteristics — shallow mass, essentially indifferent to matter, and abundant — tick off many dark matter boxes as well.
What Methods Do We Use To Search For Dark Matter?
Dark matter usually flows through Earth without interacting with ordinary matter, but it does so on rare occasions; the challenge is determining when this happens. Metal germanium crystals and liquid xenon are used as dark matter finders in experiments like LUX-ZEPLIN. These trials will be in deep underground mines by 2020, protected from cosmic radiation that strikes our planet's surface. The Axion Dark Matter Experiment, which began at Lawrence Livermore National Laboratory before relocating to the University of Washington, looks for the minute traces left by axions when they're caught in a strong magnetic field. Telescopes are also scanning the skies for telltale gamma rays if dark matter commits particle suicide and self-destructs.
Discovery
According to the Hobby Eberly Telescope Dark Energy Experiment, researchers previously predicted that stars near the galaxy's centre would travel faster than those on the galaxy's periphery. This sounds reasonable because the galaxy's core, the centre of mass, should have the most substantial gravity. Astronomers were shocked to learn that all stars orbited the centre of the Milky Way galaxy at nearly the same speed when they measured the stars that form a brilliant disk across the galaxy. From the outside, something invisible is pushing at the stars.
According to Britannica, the substance was discovered in 1933 by astronomer Fritz Zwicky. He saw that visible matter wasn't providing nearly enough mass to keep the stars from floating. According to astronomers, this effect has now been seen in other galaxies and clusters of galaxies. According to calculations, the Milky Way is surrounded by a large "halo" of a black substance. Because this halo is potentially ten times the mass of the brilliant disk, it has a significant gravitational attraction.
What Does It Consist Of?
Scientists have a few working theories, but we still don't know what it is. Meanwhile, NASA claims that we're working on an elimination procedure. Here are a few things it isn't:
- We cannot see visible stuff
- Dark clouds of ordinary stuff made up of baryon particles - Scientists would be able to discover baryonic clouds by observing the radiation that passes through them.
- Antimatter - The unusual gamma rays produced when antimatter collides with matter are invisible to scientists.
- Black holes are the size of galaxies. According to astronomers, the gravitational lenses they perceive rule out this idea.
What is Dark Energy?
According to space telescopes, the cosmos is almost perfectly flat, analyzing remnant radiation from the Big Bang (the cosmic microwave background). Unless it comes into contact with mass, light travels in straight lines. According to scientists, this makes sense only in dark energy in the universe.
Our universe's expansion is speeding up, which could be explained by dark energy. Even though we've known for almost a century that galaxies are receding from our own, scientists have long believed that matter's gravitational heft will eventually impede — or possibly reverse — cosmic expansion, ending in a Big Crunch. However, in 1998, astronomers made a startling discovery. In the distant past, a type of exploding star known as a supernova appeared to be fainter than predicted, showing that the universe is expanding at an ever-faster rate and has been for over half of its 13.8 billion-year existence. The distance between galaxies will double in 10 billion years of cosmic growth continues at its current rate.
What Is Dark Energy, Exactly?
Many astrophysicists believe that dark energy is innate to the empty vacuum of space and that it makes up the bulk of the cosmos due to its near-ubiquity. There's a lot of empty out there, after all.
How Can We Find Dark Energy?
Massive sky surveys that track the dispersion of billions of galaxies across cosmic time could reveal details about dark energy's evolution and features. The Wide-Field Infrared Survey Telescope (WFIRST) of NASA and the Euclid space telescope of the European Space Agency, and the ground-based Large Synoptic Survey Telescope set to launch in Chile in the 2020s, are all essential missions.
Discovery
The "redshift" phenomenon was discovered by famed astronomer Edwin Hubble in 1929, proving that our cosmos has been expanding since the Big Bang. Astronomers have long assumed that gravity will cause the expansion to slow down. Astronomers were stunned to learn the reverse in 1998. According to Mental Floss, astronomers used the Hubble Space Telescope to monitor distant supernovae when they saw that the universe began expanding at an even quicker rate around 7.5 billion years after the Big Bang. According to NASA, no one expected to find out that the universe was expanding faster, and scientists still don't know why. However, they can tell it exists because it impacts the universe's growth.
What Does It Consist Of?
There are various hypotheses about what dark energy is, according to NASA. It could be a natural property of space. Space is not anything, contrary to widespread assumption. It has features, such as expanding and holding its energy, as Albert Einstein's gravity theory and cosmological constant suggested.
A second explanation comes from the quantum theory of matter. "'Space' is filled with transitory ('virtual') particles that constantly develop and disappear," according to this idea. However, according to NASA, when physicists attempted to apply this theory for computations, the results were incorrect. Another availability is that dark energy is a new type of dynamical energy fluid or field, dubbed "quintessence" by some physicists. According to NASA, if this is the case, we still have no idea.
Finally, Einstein's theory of gravity could be incorrect, which would explain why dark energy does not fit into our universe equation. All of our existing knowledge and understanding of the world is predicated on Einstein's correct hypothesis, so if dark energy reveals a flaw, we'll be back to square one. Our entire concept of the universe would be thrown into disarray.
Mysteries
All of this indicates that we still don't know much about space's "black" features. One is a thing, while the other is a quality, invisible and irrational. That's why dark matter and dark energy are two of science's most intriguing topics, and researchers worldwide are racing to uncover answers to the mysteries of space. What we know now is based on a process of elimination and circumstantial evidence. We know what they aren't, we've seen the results, and there's proof that they exist. Space is frequently regarded as the ultimate representation of nothingness. However, it is far from empty. It's teeming with terrible creatures and dark forces.
Key Differences Between Dark Matter and Dark Energy in Points
- Dark matter is a type of energy, whereas dark energy is a type of invisible matter or mass.
- Dark matter, respectively, slows down the expansion of the cosmos, whereas dark energy accelerates it.
- Dark matter is only found in space, whereas dark energy can be found in space and time.
- Dark energy, compared to dark matter, is a significantly more powerful force in the cosmos.
- Dark matter is suitable for galaxy coexistence and the long-term survival of the universe, whereas dark energy is not.
Conclusion
A universe is a fascinating place. Everything around us, including planets, stars, the Milky Way galaxy, and other known elements of the cosmos, account for only 5% of the universe. According to science, dark matter and dark energy make up the rest of the universe.
The early expansion of the cosmos was driven by the energy generated by the Big Bang, but it was tiny at the time. Astronomers discovered in a 1998 research that the expansion of the universe is increasing rapidly. Dark energy was significantly more potent than dark matter in this study. Dark energy today makes up approximately 68 per cent of the universe, and several theories predict that this fraction will continue to rise over time.
Scientists have yet to determine what dark matter and dark energy are, their qualities, properties, and other details. Nonetheless, their impact on the universe separates the two. Dark matter slows the universe's expansion by holding it together, whereas dark energy is a repulsive force of energy that has accelerated its expansion. Dark matter is suitable for galaxy coexistence and the long-term survival of the universe, whereas dark energy is not.
References
- Https://astronomy.com/news/2020/03/whats-the-difference-between-dark-matter-and-dark-energy
- Https://hetdex.org/dark_energy/dark_matter.htm
