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Who are we? Where did we come from? Questions like these have been around since history began. Humans relied on the wisdom of ancestors for answers. But, we there a beginning to even history.............? Then science came along with methods of organized investigation whose results can be reproduced by other people at different times and in different places. The doors to new knowledge were opened. The Hobbit Trail outlines the milestones in Earth's history as best is currently scientifically known, Hopefully, by walking the path you will experience the opportunity to think about your planet, its physical and biologic life as well as where your life fits in. There are 25 'lollipop' markers, each having the number of years prior to now with glass plate images which depict the developments occurring at those approximate dates. The entire trail is about 2500 feet which represents the time scale for the existence of the earth- about 4.7 billion years. That divides out to 155,000 years per inch. Thus early on when there wasn't much happening, the markers are farther apart, but keep walking and things will pick up. In the last 3 markers, we couldn't physically get the markers close enough together to be accurate.
last update: 8/15/2024
Marker 1 - Formation of the Earth =approximately 4.7 billion years ago (bya)
The Sun was formed like many other stars by gravitational condensation of gas clouds in interstellar space millions of years after the big bang (c. 13-14 billion years ago). This gravity eventually became strong enough to attract physical matter in the form of rocks, meteorites, and asteroids to coalesce into a planet.
2) Our Moon is born 4.5 bya
Based on lunar data from the Apollo missions in the 1970's, it is hypothesized that a Mars sized planet (named Theia) collided with earth. This cosmic collision chunked out part of the Earth which became our Moon.
3) Water comes to Earth and the oceans are filled- 4.2 bya This theory which says that water came on comets and meteorites has recently lost favor to one that says the original rocks forming the Earth already contained water.
4) Heavy meteorite bombardment. 4.0 bya This was a period that lasted hundreds of millions of years.
5) Bacteria appear. The fossil record documents the appearance of single cell organism 3.5 bya. How did that happen?
6) Three billion years ago, oxygen production by cyanobacteria occurs during photosynthesis. This changing atmosphere kills much of the anaerobic bacteria but opens the door to new forms of life. Also during this time, the ocean tides are 1000 feet high because the Moon's gravitational pull is considerably stronger because it is closer to the Earth than it is now.
7)Plate techtonics. 2.5 bya Continents are formed in the crust layer of the Earth and they move around because of molten lava in the Earth's core. This core of metal remains molten because of radioactivity. The motion of metal creates a magnetic field which envelops the earth and shields it from the harmful radiation emitted by the nearest nuclear reactor (viz. our star the Sun or Sol as it is known by some. )
8) Eukaryotes. About 1.5 bya, the first cells with nuclei (containing genetic material like RNA or DNA) are formed. After that (1.2 bya) two types of cells are developed that can pass their distinct genetic material on to the next generation and sexual reproduction begins.
9) The ozone layer develops 600 million years ago (mya) , providing a protective shield against some of the harmful radiation of the sun.
10) Life starts to explode in the fossil record around 570 mya in the Cambrian era ( a convention of time keep by geologists using physical characteristics of rock formations. Fungi first appear in rock layers about 560 mya.
11) Fish appear 520 mya
12) Vertebrates 485 mya. Some of the sea creatures now have bony skeletons with spines, Descendents of these animals include wrasses which still exist in today's oceans.
13) Forests develop 380 mya
14) Beetles appear in the fossil record 280 mya. Also, it is thought by some scientists that the first snowball Earth occurred during this time, in which the entire planet was cold and partially covered by ice/snow. This will happen again several times.
15) Mass Extinction. shortly (geologically speaking) before the advent of the dinosaurs 225 mya, there occurred a great mass extinction in which 90-95% of marine life vanished in the Permian-Triassic geologic era.
16 Birds, which we now believe may be descendants of dinosaurs appear 150 mya.
17) Flowers apear around 130 mya
18) Thirty million years later come the bees at 100 mya.
19) Small mammals and ants appear around 80 mya. -- Yes , I know the plate depiction is not small mammals, but you get the point.
20) The presumed king of the dinosaurs , at least by modern folklore, T. Rex appears 68 mya. They disappear 3 million years later with all the other dinosaurs in what is thought to have been a worldwide extinction due to a large asteroid striking the Earth near the Yucatan peninsula in Mexico. My second side comment - so, the dinos lasted ~ 160 million years and got wiped out by a natural disaster - will humans do better?
21) Butterflies and moths, 40 mya
22) The great woolly mammoth, a relative of the modern elephant, roams the northern hemisphere 4.8 mya.
23) Two million years ago, evidence of a new primate species which walks upright (homo ) is found.
24) 350 thousand years ago, Neanderthals are found in present day Europe. 200 thousand years ago, modern humans come onto the scene. Current research believes they did intermix some, but the Neanderthals disappear about 30,00 years ago. ? The plate has a wheel in it, but that really didn't come along until 4-4000 BCE.
25) 9000 years ago, recorded history begins with the advent of writing and calculation, formation of cities and culture in the Middle East (Sumer, UR, Assyria, Babylonia, Egypt, then 'ancient' China. The use of tools is seen in the bronze and iron ages, to be succeeded by the middle ages and current modern era. Some believe that the Earth has now passed into the anthropocene era.
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