The universe is a huge and mysterious place. There are a lot of things we don’t know about it, and have yet to figure out. But of which we do know, here are some mind-blowing facts, as presented in Space.com, online platform for all things universe.
|The old universe / Photo by: NASA, ESA via Space|
1. The Universe Is Old
The universe, according to science, began with the Big Bang. It is estimated to be at least 13.7 billion years old. The universe cannot be younger than the objects contained in it. With this, scientists are guided by the ages of the oldest stars to limit the age of the universe. The figure is calculated by measuring the composition of matter and energy density of the universe, and identified by how much the universe has expanded in the past.
|The expanding universe / Photo by: NASA, ESA, E. Jullo, P. Natarajan and J-P. Kneib via Space|
2. The Universe Is Getting Bigger
The universe we live in is not unchanging, but is actually expanding. This was discovered by Edwin Hubble in 1920. Contrary to popular belief at that time, gravity cannot actually affect the growth of the universe by causing it to contract by sheer gravitational force, rather, an unknown energy is pulling it apart, and at a rate yet to be discovered.
|The speed of the universe's expansion / Photo by: NASA and WMAP via Space|
3. The Universe’s Growth Is Accelerating
In 1998, the Hubble Space Telescope found, based on distant supernovas, that the universe was expanding more slowly than it is today. An unexplainable force is driving this acceleration, called dark energy. It is among the greatest mysteries to scientists, and is believed to pull cosmos apart at increasing speeds.
|The "flat" universe / Photo by: STScl and NASA via Space|
4. The Universe May Be Flat
The shape of the universe is impacted by the pull of gravity, the density of the universe, and the rate of expansion. There are different theories based on the relationship of the 3 factors. If the density of the universe exceeds a critical value, then the universe is “closed” or is closing like the surface of a sphere. This means that the finite, growing universe may eventually collapse into itself known as the “big crunch”. If the density of the universe is less than critical density value, the shape of the universe is “open”, like a saddle, and will continue to expand indefinitely. If the density of the universe is equal to critical density, then the shape of the universe is “flat” like a sheet of paper.
|Photo by: ESA and Hubble via Space|
5. The Universe Is Filled With Invisible Objects
The universe is vast, with only 4% of stars, planets, and galaxies, detected by mankind. The other 96% is unknown and unseen. Unknown and elusive substances are called dark energy and dark matter, based on gravitational exertion on already existing, known, and visible parts of the universe.
|Echoes of the universe / Photo by: ESA LFI & HFI Consortia via Space|
6. The Universe Has Echoes From Its Birth
The background of the universe is made up of echoes of light left over from the Big Bang, with pockets of radiation. The European Space Agency’s Planck mission, the most precise views of cosmic microwave background obtained, mapped the microwave lights of the entire sky to identify clues of how the universe began, and how far long ago this was.
|Multiple universes / Photo by: Stephen Feeney UCL via Space|
7. There May Be Multiple Universes
Not just a product of fiction and comic-book fantasies, multiverses may exist, in which our universe is only one of many. From a theory called the eternal inflation, this suggests that after the Big Bang, space and time expanded at different rates and in different places, with bubble universes having separate laws of physics.