Nebulae and Tectonic Plates

Nebulae:
What Is a Nebula?
A nebula is a giant cloud of dust and gas in space. Some nebulae (more than
one nebula) come from the gas and dust thrown out by the explosion of a dying
star, such as a supernova. Other nebulae are regions where new stars are
beginning to form. For this reason, some nebulae are called "star nurseries.”
The closest nebula to us is the Helix Nebula (NGC 7293)
How do stars form in a nebula?
Nebulae are made of dust and gases—mostly hydrogen and helium. The dust
and gases in a nebula are very spread out, but gravity can slowly begin to pull
together clumps of dust and gas. As these clumps get bigger and bigger, their
gravity gets stronger and stronger.
Eventually, the clump of dust and gas gets so big that it collapses from its own
gravity. The collapse causes the material at the center of the cloud to heat up-
and this hot core is the beginning of a star.
Where are nebulae?
Nebulae exist in the space between the stars—also known as interstellar

space. The closest known nebula to Earth is called the Helix Nebula. It is the
remnant of a dying star—possibly one like the Sun. It is approximately 700 light-
years away from Earth. That means even if you could travel at the speed of
light, it would still take you 700 years to get there!
Structure of earth:
Earth’s layers: Inner core

The Earth is made up of four distinct layers:
The inner core is in the center and is the hottest part of the Earth. It is solid and
made up of iron and nickel.
With its immense heat energy, the inner core is like the engine room of the
Earth.
Earth’s Layers: Outer core:

The outer core is the layer surrounding the inner core.
It is a liquid layer, also made up of iron and nickel.
It is still extremely hot, with temperatures similar to the inner core.
Earth’s layers: Mantle

The mantle is the widest section of the Earth.
It has a diameter of approximately 2,900 km.
The mantle is made up of semi-molten rock called magma.
In the upper parts of the mantle the rock is hard, but lower down the rock is soft
and beginning to melt.
Earth’s Layers: Crust

The crust is the outer layer of the earth.
It is a thin layer between 0-60 km thick.
The crust is the solid rock layer upon which we live.
Tectonic plates
What are plate tectonics?

Plate tectonics is the theory that Earth’s outer shell is divided into several plates
that glide over the mantle, the rocky inner layer above the core. The plates act
like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is
called the lithosphere
The earth’s lithosphere is composed of seven or eight major plates and many
minor plates. The lithosphere is a rigid outermost shell of earth and is broken up
into tectonic plates. When these plates meet, their relative motion determines
the type of boundary like convergent, divergent, or transform.
Volcanic activity, earthquakes, mountain-building, and oceanic trench formation
occur along these plate boundaries. The relative movement of the plates
typically ranges from zero to 100 mm annually.
Plate Boundaries and interactions:

The Earth’s crust is broken up into pieces called plates.
Heat rising and falling inside the mantle creates convection currents generated
by radioactive decay in the core. The convection currents move the plates.
Where convection currents diverge near the Earth’s crust, pates move apart.
Where convection currents converge, plates move towards each other. The
movement of the plates, and the activity inside the Earth, is called plate
tectonics.
Plate tectonics cause earthquakes and volcanoes.
The point where two plates meet is called a plate boundary.
Earthquakes and volcanoes are most likely to occur either on or near plate
boundaries.
Different plate boundaries:
At a tensional, constructive or divergent boundary the plates move apart.
At a compressional, destructive or convergent boundary the plates move
towards each other.
At a conservative or transform boundary the plates slide past each other.
Causes of Plate Tectonics:

Plate tectonics affects humans in several important ways.
 It causes earthquakes
 It causes volcanism
 It induces recycling of elements within the biosphere and between the
geosphere and biosphere
 It causes mountain-building
Types of plate boundaries:

Plate Boundaries mainly consists of three types (fourth is a mixed type), formed
in the manner the plates shift in relative to each other. These are collectively
referred to as surface phenomena of different types. Plate boundaries are of
different types, namely:
Transform boundaries:
These boundaries happen where two lithosphere plates move apart, or maybe
further precisely, collide away from one other despite the transform faults, where
plates are neither created nor destroyed.
Divergent boundaries:
These boundaries happen when both plates move apart from one other.
Convergent boundaries:
These boundaries happen where both plates move towards one other to form a
zone of subduction or a continental collision.
Transform boundaries:
These boundaries happen when natural or human-made structures that cross a
transform boundary are offset—split into pieces and carried in opposite
directions.
Plate boundary zones:

These boundaries happens where the effects of the interactions are unclear,
and the boundaries, usually occurring along a broad belt.

Nebulae and Tectonic Plates

Uploaded by

Copyright:

Available Formats

Nebulae and Tectonic Plates

Uploaded by

Document Information

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Nebulae and Tectonic Plates

Uploaded by

Copyright:

Available Formats

Nebulae:

Nebulae exist in the space between the stars—also known as interstellar

Earth’s layers: Inner core

Earth’s Layers: Outer core:

Earth’s layers: Mantle

Earth’s Layers: Crust

What are plate tectonics?

Plate Boundaries and interactions:

Causes of Plate Tectonics:

Types of plate boundaries:

Plate boundary zones:

You might also like