From our Solar system to the edge of the unknown
(Click the blue text, where itâ€™sÂ available,Â below for more information.)
The universeÂ is commonly defined as everything thatÂ exists. It includes all kinds of physical matterÂ andÂ energy, theÂ planets,Â stars,Â galaxies, and all the contents ofÂ space.
The Big Bang
The big bang is how astronomers explain the way the universe began. It is the idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now and it could still be stretching.
The Cosmic Microwave Background radiation, or CMB for short, is a faint glow of light that fills the universe â€“ a weak uniform microwave radiation which is detectable in nearly every direction of the sky, which is believed to be evidence of the Big Bang.
The study ofÂ astronomy involves all of the objects outside Earthâ€™s atmosphere. These include the sun, Moon, planets, comets, stars, galaxies, and all other matter in the universe. People known asÂ astronomersÂ have studied these objects for thousands of years.
Laws of Nature
Gravitation, Matter and Light â€“ all interactions in the Universe are governed by four fundamental forces.
To measure the distance of a star, astronomers use a baseline of 1 astronomical unit (AU), which is the average distance between Earth and the sun, about 93 million miles (150 million kilometers).
[5AU = 5 x 93 million miles = 465 million miles away]
Light YearsÂ (ly)
A light yearÂ (symbol: ly) is the distance thatÂ lightÂ travels in empty space in oneÂ year. Since the speed ofÂ light is about 186,000 miles per second (about 300,000 km per second), then a light year is about 6 trillion miles (about 10 trillion kilometers).
[7ly = 7 x 6Â trillionÂ miles = 54 trillion miles away]
In the visible spectrum of light, the color of the light depends on the frequency -the visible spectrum is always the same for a rainbow or the separated light from a prism. The order of colors is red, orange, yellow, green, blue,Â indigo, andÂ violet.
Red shiftâ€™ is a key concept for astronomers â€“ the term can be understood literally â€“ the wavelength of the light is stretched, so the light is seen as â€˜shiftedâ€™ towards theÂ redÂ part of the spectrum.
Forms of electromagnetic radiation like radio waves, light waves or infrared (heat) waves make characteristic patterns as they travel through space â€“ each wave has a certain shape and length. The distance between peaks (high points) is called wavelength.
Nuclear energy is the energy that holds together the nucleus of atoms â€“ atoms are the most simple blocks that make up matter. Every atom has in its center a very small nucleus. Normally, nuclear energy is hidden inside the atoms. The energy released during nuclear fission or fusion, especially when used to generate electricity.
X-Rays in space
Many things in spaceÂ give offÂ X-rays, among them are black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun, and even some comets! â€“ these electrons move along the Earthâ€™s magnetic field and eventually strike the Earthâ€™s ionosphere, causing the X-rayÂ emission.
Cosmic rays are high-energy protons and atomic nuclei which move through space at nearly the speed of light. â€“ they originate from the sun, from outside of the solar system, and from distant galaxies.
According to the physics; the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.
Dark matter is composed of particles that do not absorb, reflect, or emit light, so they cannot be detected by observing electromagnetic radiation â€“ dark matterÂ is material that cannot be seen directly. We know thatÂ dark matterÂ exists because of the effect it has on objects that we can observe directly.
Neutrinos are teeny, tiny, nearly massless particles that travel at near light speeds. Born from violent astrophysical events like exploding stars and gamma ray bursts, they are fantastically abundant in the universe, and can move as easily through lead as we move through air.
AnÂ atom a fundamental piece of matter â€“ an atomÂ itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of theÂ atomÂ called the nucleus and the electrons fly around above the nucleus in a small cloud.
AnÂ elementÂ is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particularÂ elementâ€™sÂ atoms have the same atomic number.Â Elements areÂ chemically the simplest substances and hence cannot be broken down using chemical reactions.
TheÂ periodic table of the chemical elements is a list of known chemical elements -the atomic number of an elementÂ is the same as the number of protons in that particular nucleus of an atom. In theÂ periodic table the elements are arranged into periods and groups to show a row of elements across the tableÂ is called a period.
Life is the aspect of existence that processes, acts, reacts, evaluates, and evolves through growth (reproduction and metabolism) -the crucial difference between lifeÂ and non-lifeÂ (or non-livingÂ things) is thatÂ lifeÂ uses energy for physical and conscious development.
Fictional, deliberately, imaginary, or imagined, being from outer space? Who knows, but we are hunting extraterrestrials every day.