Thread by @shingaiRndoro

#UniverseOrigins (#OriginsoftheUniverse)

@gkarani1 @TTawonga

The Universe consists of 3 types of substance: normal matter, 'dark matter' & 'dark energy'. Normal matter consists of the atoms that make up stars, planets, human beings & every other visible object in th Universe.

@gkarani1 @TTawonga In the currently scientific understanding of the Universe, 70% is dark energy, 25% dark matter and 5% normal matter.

@gkarani1 @TTawonga 3/ Hydrogen is the most common element found in the universe, followed by helium; together, they make up nearly all normal or ordinary matter.

After defining what a universe is, lets move to how it all started.

@gkarani1 @TTawonga 4/ Th universe started with a #BigBang. About 13.8b yrs ago, when ultra-hot&densely packed matter suddenly&rapidly expanded in all directions at once. Milliseconds later, th newborn universe was a heaving mass of neutrons, protons, electrons, photons &other subatomic particles.

5/ Every bit of matter that makes up all the known elements in the periodic table & every object in the universe, from black holes to massive stars to specks of space dust came into existence during the #BigBang.

6/ About 100 seconds after the #BigBang, th temperature dropped 2 a still-seething 1 billion degrees Kelvin. By roughly 380,000 years later, th universe had cooled enough 4 protons&neutrons 2 come together & form lithium, helium & th hydrogen isotope deuterium...

..., while free electrons were trapped to form neutral atoms.

Bcoz there were so many protons zipping around in th early universe, hydrogen - th lightest element, with just one proton& one neutron — became th most abundant element, making up nearly 95% of th universe's atoms.

7/ According to NSA, close to 5% of the universe's atoms are helium.

Then, about 200 million years after the #BigBang, the first stars formed &produced the rest of the elements, which make up a fraction of the remaining 1% of all normal or ordinary matter in the universe.

8/ Something else came into existence during th #BigBang: dark matter. This can't be observed directly — yet — but its fingerprints are preserved in the universe's first light, or the cosmic microwave background radiation (CMB), as tiny fluctuations in radiation.

9/ Stephen Hawking proposed a description of the Universe in its entirety, viewed as a self-contained entity, with no reference 2 anything that might have come b4 it. The description is timeless, in th sense that one set of equations delineates th Universe for all time.

10/ Th origin of mass in th Universe & th Universe itself is still speculative at this point & research is ongoing.

You can read Alan Guth's "The Inflationary Universe", page 271-276 & Hawking's "A brief history of time: From the Big Bang to black holes" page 136.

11/ In quantum physics, we learn that the kernel that became our universe just randomly&spontaneously appeared.

Th #BigBang could have been the very first moment in the history of the universe or it could have come out of something bigger. Its not known quite yet.

12/ Resources:

> Read the transcript of Stephen Hawking's lecture hawking.org.uk/the-beginning-…

> Watch physicist Tom Whyntie explain the beginning of the universe for beginners, .

> Check out this video from National Geographic, .

12/ Today, no physicist would dare assert that our physical knowledge of the universe is near completion. There are continuous new discoveries & each new discovery is unlocking a Pandora's box of even bigger & deeper physics questions.

13/ Th existence, origin & nature of th universe has been a subject of explanation in almost all civilizations &cultures. Every culture known 2 anthropology has had a cosmogony, i.e. a history of how th world began &continues, of how mankind came into existence.

14/ Thru th methods of physics&astronomy developed in laboratories&observatories, it became possible 2 understand th physical universe in a rational manner & that it can be researched. This scientific dimension&capacity was dvlped in th 1st-3rd decades of th 20th Century.

15/ Th history of #cosmology (th structure of the universe) #cosmogony (the origins of the universe) neither begin nor end with modern science.

Prior to modern astronomy, ancients had an understanding of th cosmos as they experienced it & as an interpretation of their reality.

16/ Every atom of oxygen we breathe or of calcium in our bones or of iron or carbon in our musculature can be traced back 2 a very specific origin. Chemical elements are indispensable to our physical structure. They bind us to the stars is the set of chemical elements.

17/ Only hydrogen, helium, deuterium&part of lithium) were formed by th Big Bang. Th heavier chemical elements were all synthesized in th cores of stars& launched into space upon their deaths,...

...where they blended with th remains of 000s of other stars 2 form a new generation of celestial bodies. Th Sun is already a 3rd generation star & its thanks 2 this that th chemical composition of th solar system is rich enough 2 form life as we know it.

Next is #OriginsofLife.