Pulsars
- Emit quick pulses of radio waves once every second
- Bright pulsars have been observed at almost every wavelength if light
- some can be seen in visible light
- A pulsar is basically a rapidly spinning neutron star
- the magnetic field of a neutron star is about one trillion times as powerful as the magnetic field of the Earth
- The magnetic field causes the star to emit strong radio waves and radioactive particles from the north and south poles
- Different pulsars pulse at different speeds
- It is like a lighthouse
- a pulsar forms when a massive star dies and a supernova occurs
- The accuracy of the pulsar can be used to tell time much more efficiently then even atomic clocks
Galaxies
- Most of the objects that we know in space are contained in galaxies
- There is type of galaxy called the barred spiral
- Irregular galaxies are divided into two groups Im and IO
- Our Milky Way is part of a cluster called the Local Group
Clusters
- Clusters are grouped into two categories open clusters and globular clusters
- open clusters are consisted of mostly young stars around a common gravity
- globular clusters are mostly consisted of ancient stars packed together
Nebulae
- The word nebula is derived from the latin word meaning "cloud"
- Nebulae are the basic building blocks of the universe. They contain the the elements from which stars and solar systems are built.
- Nebulae get their colors from the different gases they contain. Most are composed of 10% helium, 90% hydrogen, 0.1% heavy elements.
- They are the biggest things in the universe: most of them are dozens and sometimes even hundred of light-years across
- Nebulae are divided into to 5 main groups: emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants.
Stars
- Stars don't twinkle they are just getting covered by atmospheric disruptions
- Stars are the most plentiful objects in the visible universe
- A star's brightness is known as it's magnitude
- They provide the light and energy that fuels the universe
- Stars begin as nebulae
- when the pressure of the nuclear reaction is not strong enough to equalize the force of gravity and the star will collapse
- Large stars burn their fuel faster than small stars
- stars are mainly composed of hydrogen
- stars give energy to life on Earth and essential elements
Black Holes
- formed from the cores of super massive stars
- they are regions of space where so much mass is concentrated that nothing, not even light, can escape the gravitational pull
- The escape velocity is faster than the speed of light. Since nothing can travel faster than light nothing can escape a black hole
- Einstein's theory states that gravity affects time so, because the gravity of the black hole is so strong time stands still
- The bigger the object the more time slows down
- If the sun were to become a black hole our planets would revolve around it just as they do today. Black holes only suck in matter a certain length around them
Dark Matter
- Dark matter can't be seen
- Scientists think that we only see 10% of the matter in space and the other 90% we don't see is called dark matter
- Everything in the universe is mutually attracted to anything else
Quasars
- They are the brightest and most distant objects in the known universe
- They have the largest red shift of any other objects in the cosmos