astronomy stars, galaxies, and the universe tools of ancient astronomy
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AstronomyAstronomy
Stars, Galaxies, and the UniverseStars, Galaxies, and the Universe
Tools of Ancient Astronomy
Tools of Ancient Astronomy
Tools of Modern Astronomy
Tools of Modern Astronomy
The Electromagnetic Spectrum
The Electromagnetic Spectrum
The electromagnetic spectrum is a list of electromagnetic waves placed in order of increasing energy.
The electromagnetic spectrum is a list of electromagnetic waves placed in order of increasing energy.
Tools of Modern Astronomy
Tools of Modern Astronomy
Astronomers use tools that focus different types of electromagnetic energy to study distant objects in space.
Astronomers use tools that focus different types of electromagnetic energy to study distant objects in space.
Telescopes
What are these tools called?
Radio Wave TelescopesRadio Wave Telescopes
World’s Largest Radio Telescope: Arecibo Facility in
Puerto Rico measures 1000 feet across, 167
feet deep, and 20 acres.
Can we hear radio waves?No, radios convert electromagnetic radiation to sound energy we can hear.
Infrared TelescopesInfrared Telescopes
The United Kingdom Infrared Telescope in Hawaii.
How does your body interpret infrared radiation?
Heat
Visible Light TelescopesVisible Light Telescopes
The Hubble Telescope is a light telescope that floats in space!
Why would Hubble Telescope pictures be clearer than ones taken from Earth’s surface?There is no
atmosphere to look through.
Ultraviolet TelescopesUltraviolet Telescopes
The Hopkins ultraviolet telescope being released by the Space Shuttle.
Why would an ultraviolet telescope need to be in space?
Earth’s atmosphere blocks ultraviolet radiation.
X-Ray TelescopesX-Ray Telescopes
The Chandra X-Ray Telescope
What else do we use x-rays for?
Medical diagnosing like to see if you have a broken bone.
Gamma Ray TelescopesGamma Ray Telescopes
The gamma-ray telescope on Mt. Hopkins, Arizona.
Besides stars, what else emits gamma-rays?
Nuclear Explosions.
Characteristics of StarsCharacteristics of Stars
1) brightness, which astronomers describe in terms of magnitude or luminosity;
2) color; 3) surface temperature; 4) size; 5) mass (amount of matter)
1) brightness, which astronomers describe in terms of magnitude or luminosity;
2) color; 3) surface temperature; 4) size; 5) mass (amount of matter)
Magnitude and luminosityMagnitude and luminosity
A star's brightness as viewed from Earth is its apparent magnitude.
Luminosity is the rate at which a star emits energy.
A star's brightness as viewed from Earth is its apparent magnitude.
Luminosity is the rate at which a star emits energy.
Color and TemperatureColor and Temperature
A star's color depends on its surface temperature.
Dark red stars 2500 K. Bright red stars 3500 K Yellow stars (e.g. the Sun) 5500
K. Blue stars 10,000 to 50,000 K
A star's color depends on its surface temperature.
Dark red stars 2500 K. Bright red stars 3500 K Yellow stars (e.g. the Sun) 5500
K. Blue stars 10,000 to 50,000 K
Size and MassSize and Mass
Astronomers measure the size of stars in terms of the sun's radius.
Astronomers express the mass of a star in terms of the solar mass, the mass of the sun.
The mass of the sun is written out as 2 followed by 30 zeros.
Astronomers measure the size of stars in terms of the sun's radius.
Astronomers express the mass of a star in terms of the solar mass, the mass of the sun.
The mass of the sun is written out as 2 followed by 30 zeros.
Nebula to GlobuleNebula to Globule
New stars form from large, cold clouds of dust and gas.
Stars usually start to form in a nebula, a cloud of interstellar hydrogen gas and dust.
When the gas and dust are forced together, they form a slowly rotating globule. Gravitational forces survive through gas pressure and the globule starts to collapse, then the cooling occurs and the spin increases.
New stars form from large, cold clouds of dust and gas.
Stars usually start to form in a nebula, a cloud of interstellar hydrogen gas and dust.
When the gas and dust are forced together, they form a slowly rotating globule. Gravitational forces survive through gas pressure and the globule starts to collapse, then the cooling occurs and the spin increases.
Globule to StarGlobule to Star The globule starts to change into a
protoplanetary disk (which could also become a planet) and a central core (which will become a star).
The core of the protoplanetary disk starts to increase in temperature.
When fusion starts to begin, that's when a protostar has been formed. If the temperature reaches about 27,000,000,000°F, nuclear fusion begins, then stars start to form.
The globule starts to change into a protoplanetary disk (which could also become a planet) and a central core (which will become a star).
The core of the protoplanetary disk starts to increase in temperature.
When fusion starts to begin, that's when a protostar has been formed. If the temperature reaches about 27,000,000,000°F, nuclear fusion begins, then stars start to form.
A Star is BornA Star is Born
When stars are born they come in different sizes and their color range from blue to red.
The size of a star depends on the gas and dust that have been collected during the birth of the star.
The color of the star depends on the surface temperature of the star.
The more mass a star starts out with the hotter and brighter it will be.
When stars are born they come in different sizes and their color range from blue to red.
The size of a star depends on the gas and dust that have been collected during the birth of the star.
The color of the star depends on the surface temperature of the star.
The more mass a star starts out with the hotter and brighter it will be.
Lives of StarsLives of Stars
Throughout a star's life, it tries to fight the inward pull of the force of gravity.
Stars live different lengths of time depending on the size.
The hotter and brighter a star is, the shorter their lives are.
Throughout a star's life, it tries to fight the inward pull of the force of gravity.
Stars live different lengths of time depending on the size.
The hotter and brighter a star is, the shorter their lives are.
Long Live the Stars!Long Live the Stars!
For example, the sun would live for about 10 billion years while a star 20 times bigger than that will only live for 10 million years.
For example, the sun would live for about 10 billion years while a star 20 times bigger than that will only live for 10 million years.
A Star’s Final HoursA Star’s Final Hours
When a star's supply of hydrogen runs out, it eventually dies.
The death of a star depends on what type of star it is and the size of the star.
Stars will either become a black dwarf, a neutron star or a black hole, depending on the size of a star.
When a star's supply of hydrogen runs out, it eventually dies.
The death of a star depends on what type of star it is and the size of the star.
Stars will either become a black dwarf, a neutron star or a black hole, depending on the size of a star.
The Evolution of StarsThe Evolution of Stars Main Sequence Phase - Longest phase of a
star’s life - hydrogen is burning in core - fusion energy and gravity are balanced
Red Giant Phase - all hydrogen in the core has become helium - gravity becomes stronger and the star begins to collapse
White Dwarf Phase - shells are blown away - remaining core is carbon and oxygen
Black Dwarf Phase - core has become so cold that it is difficult to see - the star has died
Main Sequence Phase - Longest phase of a star’s life - hydrogen is burning in core - fusion energy and gravity are balanced
Red Giant Phase - all hydrogen in the core has become helium - gravity becomes stronger and the star begins to collapse
White Dwarf Phase - shells are blown away - remaining core is carbon and oxygen
Black Dwarf Phase - core has become so cold that it is difficult to see - the star has died
SupernovaSupernova
That’s not the end! The collapsing core shrinks to a
size about 6 miles in diameter Then it “rebounds” outwards in
less than a second, sending all of its gases and dust to be used again for the birth of a new star.
That’s not the end! The collapsing core shrinks to a
size about 6 miles in diameter Then it “rebounds” outwards in
less than a second, sending all of its gases and dust to be used again for the birth of a new star.
What’s left behind?What’s left behind?
The gravity of the collapsing star that is left behind becomes a Black Hole
a region of space whose gravitational force is so strong that nothing can escape from it.
A black hole is invisible because it traps even light.
The gravity of the collapsing star that is left behind becomes a Black Hole
a region of space whose gravitational force is so strong that nothing can escape from it.
A black hole is invisible because it traps even light.
What’s at the center of a Black Hole?
What’s at the center of a Black Hole?
All its matter is located at a single point in its center.
This point, known as a singularity, is much smaller than an atomic nucleus.
All its matter is located at a single point in its center.
This point, known as a singularity, is much smaller than an atomic nucleus.
A X-ray telescope picture of a black hole.
Black HoleBlack Hole
Star SystemsStar Systems
A star system is a small number of stars which orbit each other bound by gravitational attraction.
A large number of stars bound by gravitation is generally called a star cluster or galaxy.
A star system is a small number of stars which orbit each other bound by gravitational attraction.
A large number of stars bound by gravitation is generally called a star cluster or galaxy.
GalaxiesGalaxies
A galaxy is a massive, gravitationally bound system consisting of stars, an interstellar medium of gas and dust, and dark matter all orbiting a common center of mass.
Our galaxy is called the Milky Way
A galaxy is a massive, gravitationally bound system consisting of stars, an interstellar medium of gas and dust, and dark matter all orbiting a common center of mass.
Our galaxy is called the Milky Way
The UniverseThe Universe
The Universe is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them.
Astronomical observations indicate that the universe is 13.73 ± 0.12 billion years old[1] and at least 93 billion light years across.
The Universe is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them.
Astronomical observations indicate that the universe is 13.73 ± 0.12 billion years old[1] and at least 93 billion light years across.
History of the UniverseHistory of the Universe
According to the prevailing scientific theory, the universe has expanded from a gravitational singularity known as the Big Bang, a point in space and time at which all the matter and energy of the observable universe were concentrated.
According to the prevailing scientific theory, the universe has expanded from a gravitational singularity known as the Big Bang, a point in space and time at which all the matter and energy of the observable universe were concentrated.
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