Formation of the Moon
Where did the moon come from?
The fashionable theory is that the Moon is the result of a collision during the birth of the Solar
System 4500 million years ago. When the Earth was nearly complete, a gigantic wandering asteroid
the size of Mars supposedly collided with our planet, flinging vaporized rock and debris from both
bodies into space. Some of it went into orbit around the Earth, and congealed to make the Moon.
Collision theory for formation of the moon
Billions of years ago, a version of our Earth that looks very different than the one we live on today
was hit by an object about the size of Mars, called Theia – and out of that collision the Moon was
formed. How exactly that formation occurred is a scientific puzzle researchers have studied for
decades, without a conclusive answer.
Most theories claim the Moon formed out of the debris of this collision, coalescing in orbit over
months or years. A new simulation puts forth a different theory – the Moon may have formed
immediately, in a matter of hours, when material from the Earth and Theia was launched directly
into orbit after the impact.
Nebulae
Nebulae are interstellar clouds of gas and dust. Many nebulae are formed from the remnants of dying
stars. Nebulae are often also regions where new stars are born. Nowadays, the term 'nebula' refers to
an interstellar cloud of dust and gas.
Stellar nurseries
A stellar nursery is a cosmic cradle where stars are born. Amidst clouds of gas and dust, gravity weaves
its magic, collapsing material into glowing orbs that light up the universe. These celestial birthplaces
are not just visually stunning, but they're also key to understanding our cosmic origins.
Movement of tectonic plates.
Convection currents drive the movement of Earth's rigid tectonic plates in the planet's fluid
molten mantle.
Scientists have theorized three mechanisms that cause plate movement on Earth. These three
mechanisms are thermal convection, ridge push, and slab pull.
There are two main factors that drive the movement of plate tectonics on Earth. These factors are
heat and gravity.
Thermal convection - Convection is the transfer of heat from one place to another due to the
movement of fluid.
Ridge push – Magma rises as the plates move apart. The magma cools to form new plate material.
As it cools it becomes denser and slides down away from the ridge. This causes other plates to move
away from each other.
Slab pull – The denser plate sinks back inti the mantel under the influence of gravity. It pulls the rest
of the plate along behind it.
Evidence of tectonic plates.
Modern continents hold clues to their distant past. Evidence from fossils, glaciers, and
complementary coastlines helps reveal how the plates once fit together.
Fossils tell us when and where plants and animals once existed. Some life "rode" on diverging
plates, became isolated, and evolved into new species. Other life dispersed to new areas as
continents reconnected, oceans narrowed, or chains of volcanic islands formed. Finding identical or
similar fossils in areas separated by vast distances were some of the first clues that scientists used
to reconstruct past plate movement. This distribution of fossils led to theories that the southern
continents were once joined in a supercontinent called Gondwana.
Similar geologic formations on different continents show historic land connections. Antarctica’s
mountains are an extension of South America’s Andes. If Southern Hemisphere continents were
reassembled into a single landmass, glacial remnants in Africa and India would realign.
