The universe we know today is a result of centuries of studies and observations conducted by astronomers all over the world. Although the earliest model of the universe was established by the ancient Indian and Greek philosophers, more accurate astrophysical studies were first done by Polish astronomer Nicolaus Copernicus, who was followed by the likes of Tycho Brahe and Johannes Kepler.
So what exactly is the universe? The universe is simply all of space and time and all the contents in it. Since we can observe just a teeny-tiny part of the universe, scientist have developed theories and hypothesis about the birth of the universe itself, workings and how it will end.
Here, you will find many facts about the universe that were earlier unknown to you.
25. According to the Big Bang theory, the estimated age of the universe is about 13.7 billion years. However, we can now observe more distant objects further than 13.7 billion years because space itself has expanded.
24. The word ‘universe’ is derived from old French word ‘univers,’ which is believed to be derived from Latin ‘universum‘ itself. The Latin word ‘universum’ was possibly used for the first time by Roman politician Marcus Cicero and other Latin philosophers.
23. Our Milky Way galaxy is part of a group of galaxies known as the Local Group, which contains more than 54 galaxies. The Local Group in turn is part of the much larger Virgo Supercluster.
The Virgo Supercluster
22. Our nearest galactic neighbor is the Andromeda galaxy, located approximately 2.5 million light years away from the Earth. This gigantic spiral galaxy is about 220,000 light years wide and it is also the largest galaxy in the Local Group.
21. A study conducted by the Spitzer Space telescope in 2006 revealed that the Andromeda Galaxy hosts about one trillion stars, way more than the Milky Way’s 200-400 billion stars.
20. Based on data gathered by the WMAP (Wilkinson Microwave Anisotropy Probe) and FIRAS (Far InfraRed Absolute Spectrophotometer), researchers are able to determine the average temperature of the universe, which is about 2.72548 K.
19. Astronomers believe that there are three types of black holes present in the universe. Two out of those three are stellar black holes, which forms after the collapse of a massive star. The second is supermassive black holes, mostly found near the galactic core. And the third type of black hole is known as intermediate mass black holes, as it has a mass somewhere between the first two types.
A supermassive black in the center of the Milky Way
18. Though, the birth and death of the stars happen in a long stretch of time, the star forming process however is more frequent. After observing various supernova events within our galaxy, researchers have roughly estimated that about 275 million stars are born through the universe (observable universe). In one year the number is 100 billion.
17. Many theorists believe that the universe is fine tuned. The fine-tuned universe hypothesis argue that the life enabling conditions in the universe can only emerge when some fundamental or dimensionless physical constants (such as the speed of light and gravitational constant, etc.) lie within a certain low range of values. If any the these physical constants were different, even slightly, the life as we know would never materialize.
16. You are probably aware about the multiverse hypothesis. Well, the multiverse hypothesis advocate that the universe we live in is a part of the other disconnected universe. These universes together incorporate everything we know; space, time, matter and energy. Multiverse are often called parallel universe.
15. Located about 1 billion light years away from the Earth in the constellation Virgo, IC 1101 is perhaps the largest known galaxy in the observable universe. How large you ask, the galaxy has an effective radius of 210,000 light years. This gigantic galaxy was discovered in the year 1790 by astronomer Frederick William Herschel I.
Image of galaxy IC 1101 taken by the Hubble Space Telescope
14. What is the shape of our universe, any guess? Researchers are considering three possibilities; positively-curved, negatively-curved, and flat. It remains one of the biggest mysteries of the universe.
13. In 2015, astronomers located the largest known void in the nearby space, about 1.8 billion light years across. Voids are empty spaces between galaxies and other giant structures. On average, voids in the universe are 30 million to 400 million light years wide (in diameter).
12. The Hercules-Corona Borealis Great Wall is a mass concentration of galaxies spanning over relatively a huge region in the space. It is most probably the largest known single mass concentration in the universe. It was discovered by a group of international astronomers led by István Horváth and other researchers.
Read: Different Types of Galaxies In The Universe
11. Before the arrival of the Hooker Telescope in 1919, human understanding of the universe was limited just to the Milky Way. However, observation conducted using the telescope, Edwin Hubble was successfully able to identify the distinct Cepheid variables in another spiral nebulae and later proved that Triangulum and Andromeda Nebula are entire galaxies outside the Milky Way.
RS Puppis is one of the brightest known Cepheid variable stars in the Milky Way galaxy Image Courtesy: Hubble Space Telescope
10. Supermassive black holes are generally located in the galactic center of medium and large galaxies just like our own. However, a team of astronomers in 2014 discovered a monstrous black hole, five times massive than the black hole at the center of the Milky way, at the center of tinny-tiny galaxy named M60-UCD 1. The M60-UCD 1 dwarf galaxy that hosts no more than 140 million stars and a diameter of just 300 light years.
9. In 1996, a team of astronomers led by Rudolph Schild discovered an anomaly in a gravitationally lensed image of a distant object known as Twin Quasar. The gravitational lensing is caused by the a gigantic spiral galaxy YGKOW G1, located in the line of sight between the Earth and the Quasar.
The team announced that this anomaly might be a planet about 3 times the Earth masses in that galaxy. If confirmed, this planet would be the farthest ever observed planet about 4 billion light years away from the Earth. However, it might have been one in a lifetime alignment. The planet has never been observed since then.
8. Various researches have shown that matter and antimatter in the universe is not present in balanced amounts, instead matter appears to be more abundant than antimatter. Scientists also suspect that this asymmetry is related to the CP violation.
Furthermore and more importantly, this asymmetry is partly responsible for the existence of the universe in itself. If matter and antimatter was produced at equal proportion at the time of the Big Bang, they would have annihilated each other completely.
7. The hot, dense state of the universe just after the Big Bang is known as the Plank epoch. It is a short period spanning from absolute zero to 10-43 seconds, which is also known as one Plank time. During this time, scientists believe that all the energy types were concentrated into one extremely dense state, where all the fundamental forces could have been unified.
6. Next came the quark, hadron and lepton epochs. All three combined, these epochs lasted for less than 10 seconds.
5. The universe is mostly composed of dark energy (68.3%) and dark matter (26.8%). The remaining 4.9% is baryonic matter such as atoms, stars and galaxies. Antimatter and electromagnetic radiation constitute less than 0.01% of the universe.
4. A long standing controversial argument among astronomers is that whether the universe is finite or infinite. Because we can only observe space within the observable universe, it is almost impossible to determine this. If the universe is finite, then it may have a diameter of 156-554 billion light years.
3. Our universe is slowly dying. According to a research conducted by a team of international scientists, the total energy output of the current universe is only half of what was about 2 billion years ago. The team measured the energy output of more than 200,000 galaxies across different wavelengths.
However, this is not the first time researchers have discovered that the universe is slowly dying. In 1990s, NASA’s WISE and GALEX detected a significant decrease in the amount of energy output over most wavelengths.
2. The well known Lambda-CDM model is a version of the Big Bang model with Lambda or a cosmological constant and cold dark matter. The Lambda-CDM model is perhaps the simplest model of the universe that adequately explains different observations about the universe.
Timeline of the universe
1. What will be the fate of the universe? The ultimate fate of the universe depends upon the pressure and density of the matter in the universe. If it’s less than the critical density of the universe, then the universe will expand forever. This situation is known as “Big Freeze”. Due to the continuous expansion of the universe, it will slowly cool down below a level in which no life can survive.
Read: 11 Mysterious Signals From Outer Space
On the other hand, if the density of the universe is greater than the critical density, then the universe will collapse on itself due to gravity. It is also known as the “Big Crunch”.
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