Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay
All the above are made of atoms (Normal Matter)
These are made of subatomic particles not arranged into atoms
Both types of matter consist of independent atomic particles rather than atoms
The sky starts just above your outstretched fingertips. Weather phenomena of all kinds occur in the sky. Astronomers are mostly interested in effects that are due to the physics of light, or occur at altitudes above normal weather, say 10 km or more.
Optical Effects
High Clouds: There are a number of extremely high clouds that are best seen after sunset, because they remain lit by the Sun long after clouds at low altitudes are dark. Some are made of sulfuric or nitric acid droplets, others of ice. How water gets to such high altitudes is a mystery, but there is some indication that exhaust from the Space Shuttle may play a role. Rocket launches also create extreme altitude clouds that are contorted into bizarre shapes by high altitude winds.
Meteors: Meteors are small objects that enter the atmosphere and glow due to frictional heating. Most vaporize at high altitudes but rarely, larger objects make it to the surface and are known as meteorites.
Artificial Satellites: On a typical night one can see an artificial satellite every 20 minutes or so. They look like faint moving stars. The International Space Station can rival the brightest stars. A fleet of communications satellites called Iridium has solar panels that give off intense flashes lasting a few seconds.
Auroras: Auroras are high altitude gases that glow because of bombardment by fast-moving solar particles. Mostly the earth's magnetic field funnels these particles toward the poles, but large outbursts from the Sun can cause auroras at even low latitudes.
Sprites: Long reported by high altitude pilots, these are still poorly understood red and blue electrical discharges above thunderstorms. They have been photographed, so they are real.
€The Sun (a typical star) €Planets €“Rocky Inner Planets €“Outer Gas Giants (€œJupiter plus debris€) €“Rocky and Icy Satellites €Small Objects €“Dwarf and Minor Planets €“Comets €“Meteoroids €“Dust
A Rocky Planet
Gas Giant Planet
An Ice World (Enceladus)
An Asteroid (Itokawa)
Comet Holmes 2007
Halley€™s Comet
All objects exist because of a balance between gravity and some force that prevents the object from collapsing. Paramecia, Petunias, People and Planets are prevented from collapsing by the bonding forces between atoms.
Normal (Main Sequence) Stars
Light years apart
Giants and Supergiants
White Dwarfs
Red Dwarfs
Brown Dwarfs
Neutron Stars (including pulsars)
Black Holes
The Stellar Zoo
Multiple Stars (half or more)
Variable Stars
Novae
Supernovae
Dust and Gas Clouds
Planetary Nebulae
Emission Nebulae
Reflection Nebulae
Dark Nebulae
Molecular Clouds
Supernova Remnants
Star Clusters
Open Clusters
Globular Clusters
Show us where we are in the Galaxy
Clusters are important for demonstrating how stars evolve
Batches of stars all formed at the same time
An Open Star Cluster: The Pleiades
A Globular Star Cluster
Galaxies
About 100,000 light years across
100,000 to many millions of light years apart
Dwarf Galaxies (millions or billions of stars)
Spiral Galaxies (100's of billions of stars)
Irregular Galaxies
Galaxies can have satellite galaxies
Elliptical Galaxies (trillions of stars)
Form by mergers of other galaxies
A Dwarf Galaxy
The Milky Way?
Irregular Galaxy
A Ring Galaxy
Elliptical Galaxy
Clusters and Super clusters of galaxies
Giant Voids
Dark (non-luminous) matter
Dark Energy
Cosmic Microwave Background
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Created 08 July 2008, Last Update 17 January 2020