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Big Bang
The origin of the universe, after a microscopic ball of hot fog inflated and created matter that is still expanding the cosmos that we have today. -
First Stars Are Born
After a long period of darkness in the universe, perhaps 100 million years, stars finally formed. Models that were created by cosmologists tell us that the first stars were most likely quite huge and bright, and that the stars changed the dynamics of the cosmos by heating and ionizing the surrounding gases. The stars produced the first source of heavy elements. -
First Galaxies Form
While it took maybe 100 million years for stars to form, almost a billion years passed before galaxies were formed as well. Matter and stars gradually formed to make the galaxies, which merged with others to form bigger galaxies. -
The Milky Way Galaxy Forms
We know that galaxies are formed when stars gravitate into groups. The oldest of the groups are called "globular clusters", and some of the globular clusters that are in the Milky Way date back to the earliest stages of the Universe. While the Milky Way produces stars (and still does - more than 7 stars per year), it formed mostly by swallowing up smaller galaxies, which is why the Milky Way is referred to as a "cannibal" galaxy. It is the galaxy that we live in. -
The Solar System Forms: The Sun, Planets, Asteroids, Moons (PART 1)
The solar system was formed when a cloud of space dust and gas in a nebula collapsed from being compressed by a supernova explosion. When it fell in on itself, a disk of surrounding material formed, containing so much pressure that hydrogen atoms fused into helium and released an extremely large amount of energy. This energy created the Sun at the centre of the disk. ... -
The Solar System Forms: The Sun, Asteroids, Moons (PART 2)
... The Sun absorbed most of the material in the disk, but there were still remains that clumped and collided together with the force of gravity, eventually forming planets and their moons. The rockier planets were closer to the sun, while the gaseous planets were further away so they could survive. There are still remains in the solar system today that couldn't form into anything, known to us as "asteroids". -
First Single Celled Organisms
Scientists do not yet know how life on Earth came to be, but single-celled micro-organisms called prokaryotes appeared on Earth almost four billion years ago. Prokaryotes are organisms that do not contain a cell nucleus or membrane and can sometimes have multi-cellular stages in their life-cycles. There are two main types of Prokaryote; bacteria and archaea. -
First Multi-Celled Organisms
It took longer for multi-cellular organisms to evolve; they didn't appear until about 600 million years ago. Unlike single celled organisms, multi-celled organisms have a cell nucleus and contain complex structures enclosed within membranes. All animals, land plants and most fungi are multi-celled organisms. -
First Animals with Shells and Hard Parts (PART 2)
... The fossils that were analysed were from a period called the "Early Cambrian". During the Early Cambrian there was a huge diversity of animal life in the oceans, and this period particularly marked the first general occurrence of animals with shells and hard parts. A lot of these animals had complex external armours made up of many tiny pieces and, when they died, the armour fell apart. -
First Animals with Shells and Hard Parts (PART 1)
With information from fossil remains, scientists can tell us what evolution was like in the period of their dating and what the animals were like. The first animals with shells were sea creatures that measure a few centimetres in length, dating back to about 520 million years ago. ... -
First Vertebrates
A vertebrate is an animal that has a backbone or spinal column. The first known vertebrate fossils were found at the Chengjiang locality in China, and date back to the Early Cambrian period. One species of these vertebrates, Haikouichthys, are small, tapered, streamlined animals that have eyes, a brain, pharyngeal arches, a notochord, and rudimentary vertebrae. -
Life Still Confined to the Sea, Seaweed is the Only Plant
During the Proterozoic period, all life was confined to the sea and seaweed was one of the first multi-celled plants. During this period, the Earth was much colder than it is now, most of the water was probably frozen into ice, and the oceans were shallower. Seaweed evolved to live in these conditions where there was enough sunlight for photosynthesis. -
First Signs of Land Plants and Animals (PART 1)
Researchers found that land fungi had evolved on Earth by about 1,300 million years ago, and land plants 600 million years later during the Ordovician period. They were non-vascular plants, like mosses and liverworts, that didn't have deep roots. ... -
First Signs of Land Plants and Animals (PART 2)
... It is said that these plants increased the amount of oxygen in the Earths atmosphere and decreased the percentage of carbon dioxide, leading the the belief that the plant-life was the cause of the Snowball Earth eras (when ice periodically covered the globe), and the Cambrian Explosion, when many new species of animals were appearing. -
First Insects and Spiders (PART 1)
It is estimated that insects originated on Earth about 480 million years ago, during the Ordovician period, around the same time as plants appeared. Insects evolved from a group of crustaceans, and the first were land-dwellers until they evolved wings in the Devonian period. ... -
First Insects and Spiders (PART 2)
... The evolution of spiders has been going on for over 380 million years, since the first spiders evolved from crustaceous chelicerate ancestors. The Rhyniognatha hirsti is the oldest known insect, estimated to be around 400 million years old. -
Amphibians Dominant
The earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins. During the Carboniferous and Permian periods, they became the dominant land animals on Earth. Some amphibians grew up to 15 feet long, which is considered a huge size for 300 million years ago, and would scare off smaller animals. -
Mammal-Like Reptiles Appear
These "mammal-like" reptiles are "Synapsids"; a group of mammals and animals that are more closely related to mammals than to other amniotes (birds or reptiles). They had a number of characteristics that are found in mammals, however, they were extremely varied. Some weighed almost nothing, while others weighed several hundred tons. Some would only dwell on the land, while others could fly or only live in the sea. -
Dinosaurs Abundant, First Birds Appear
Dinosaurs first appeared in the Triassic period but were dominant/abundant during the Jurassic period, when the supercontinent Pangea was beginning to drift apart and the climate was hot and dry, almost tropical. Carnivorous theropods were particularly abundant. The evolution of birds also began in the period, the earliest deriving from the group of theropoda dinosaurs called "Paraves". The earliest known bird is the Archaeopteryx lithographica. -
Dinosaurs Extinct, Increase in Diversity of Mammals of All Kinds (PART 1)
65 million years ago, the Cretaceous–Paleogene extinction event happened; more than half of the world's species were wiped out, including dinosaurs, mosasaurs, plesiosaurs, pterosaurs, vegetation, etc. The cause is still unkown, but scientists hypothesize that it could have been an asteroid or comet, or a massive bout of volcanism. ... -
Dinosaurs Extinct, Increase in Diversity of Mammals of All Kinds (PART 2)
... A lot of competitors and predators disappeared, meaning mammals had more freedom that they took advantage of when the diversity in all sorts of mammals increased 10 million years after the event during the Paleocene period. -
Anatomically Modern Humans Appear
Modern humans, also known as "Homo sapiens", first began to evolve nearly 200, 000 years ago from archaic humans primarily in East Africa. Modern humans did not come from Neanderthals because they were around at the same time. However, it is likely that the two descended from Homo heidelbergensis. -
Red Shift
When a sound source is blue shifted, the source is moving towards you and the wavelength is compressed and higher in both frequency and pitch. When the sound source is red shifted, it is moving away from you and the wavelength is stretched and lower in both frequency and pitch. This also applies to light.
Red Shift supports the Big Bang theory because the light from distant galaxies is red shifted, meaning it is moving away which proves that the Universe is still expanding. -
Background Radiation/Cosmic Microwave Background (PART 1)
The Cosmic Microwave Background (CMB) is radiation that fills the universe and can be detected in every direction. Because Microwaves are invisible to the naked eye, instruments are required to view them. When astronomers look out into deep space, they are also looking back into deep time and can see the CMB radiation saturating space beginning at about 378, 000 years after the Big Bang. -
Background Radiation/Cosmic Microwave Background (PART 2)
In the 20th century there were two theories for the beginning of the universe; the "Steady State theory" (suggested that matter is continuously created as the universe expands, the density of the universe remains the same and that the universe has always existed) and the Big Bang theory (suggested that the expanding universe must have been denser in the past and had a point of infinite density at the beginning). -
Background Radiation/Cosmic Microwave Background (PART 3)
It was theorized that if the Big Bang theory was correct, the universe would be filled with background radiation left over from the creation of the universe, which there was and therefore the theory was correct.
