The relationship between the number of moons and the planet size is that the bigger the planet the more moons it seems to have.
The Ingredients for Life
1. Liquid Water
2. Chemical building blocks like carbon, hydrogen and nitrogen
3. An energy source
Panspermia Theory
Panspermia Theory suggests that life seeds came from outer space and planets exchanged life. Panspermia literally means seeds everywhere.
Panspermia suggests that life could have existed on another planet and moved to Earth. Statistics have showed 7.5% of rocks from Mars reach Earth. The rocks would travel between less than 100 years to 16,000 years and more to get to earth.
Some of the proponents include Sales Gyon de Montlivant, who proposed life came from the moon, H.E. Richter, who suggested life came from meteorites,comets, and Svante Arrhenius, who came up with Panspermia.
Evidence for Panspermia
1. Bacteria can survive harsh environment of space
- Ultraviolet radiation
- Protons bombardments
- Cold
2. Evidence that meteorites contain life
- Amino acids (left handed in helicity)
- Bacteria
- Carbon
- Protected inside rocks
3. Bacteria can live for a long time in sleeping state until awakened
4. Mars is safer than Earth (less bombardments and less gravity)
5. Mars not as hot as Earth in early development
6. Mars had have had oxygen back then when Earth did not.
Earth is special because its seas contain the key ingredients for life.
Origin of life
The origin of life is the key to the meaning of life. Scientists define life as several characteristics, but the most important aspect is reproduction and metabolism.
The others are:
Scientists say that the odds of producing the right proteins by chance are something like 1040,000. This can be compared to a whirlwind sweeping through a junkyard and producing a fully-functional Boeing 747.
The theories presented on this website are all theories and are not proven to be facts. There are, though, scientific evidence that support and also challenge these theories.
Nebulae
Originally, the word "nebula" referred to almost any extended astronomical object (other than planets and comets). The etymological root of "nebula" means "cloud". As is usual in astronomy, the old terminology survives in modern usage in sometimes confusing ways. We sometimes use the word "nebula" to refer to galaxies, various types of star clusters and various kinds of interstellar dust/gas clouds. More strictly speaking, the word "nebula" should be reserved for gas and dust clouds and not for groups of stars.
Originally, the word "nebula" referred to almost any extended astronomical object (other than planets and comets). The etymological root of "nebula" means "cloud". As is usual in astronomy, the old terminology survives in modern usage in sometimes confusing ways. We sometimes use the word "nebula" to refer to galaxies, various types of star clusters and various kinds of interstellar dust/gas clouds. More strictly speaking, the word "nebula" should be reserved for gas and dust clouds and not for groups of stars.
Galaxies
Early in this century, there was a great debate as to the nature of the nebulae like this one which at that time could not be resolved into individual stars. Thanks in large part to the work of whose famous paper "The Realm of the Nebulae" finally put the issue to rest, we now know that these are really vast conglomerates billions of stars which are very much more distant from the than other nebulae. Our own Milky Way galaxy is just one of the billions of galaxies now known to exist. A typical galaxy is 100,000 in diameter. (M 51 shown; see the for more examples.)
Globular Clusters
Globular clusters are gravitationally bound groups of many thousands (sometimes as many as a million) of stars. They consist primarily of very stars. Globular clusters are not concentrated in the plane of the galaxy but rather are randomly distributed throughout the halo. There are several hundred globular clusters associated with our galaxy. A typical globular cluster is a few hundred light-years across. (M 13 shown; see the for more examples.)
Open Clusters
Open clusters are loose aggregations of dozens or hundreds of stars. They are generally not gravitationally bound and will disperse in a relatively short period of time, astronomically speaking. They are often associated with more diffuse nebulosity, as well. Also called "galactic clusters" because they are usually found in the plane of the galaxy. A typical open cluster is less than 50 light-years across. (M 44 shown; see the for more examples.)
Emission Nebulae
Emission nebulae are clouds of high temperature gas. The atoms in the cloud are energized by ultraviolet light from a nearby star and emit radiation as they fall back into lower energy states (in much the same way as a neon light). These nebulae are usually red because the predominant emission line of hydrogen happens to be red (other colors are produced by other atoms, but hydrogen is by far the most abundant). Emission nebulae are usually the sites of recent and ongoing star formation. ( shown)
Reflection Nebulae
Reflection nebulae are clouds of which are simply reflecting the light of a nearby star or stars. Reflection nebulae are also usually sites of star formation. They are usually blue because the scattering is more efficient for blue light. Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae. ( shown)
Dark Nebulae
Dark nebulae are clouds of which are simply blocking the light from whatever is behind. They are physically very similar to reflection nebulae; they look different only because of the geometry of the light source, the cloud and the Earth. Dark nebulae are also often seen in conjunction with reflection and emission nebulae. A typical diffuse nebula is a few hundred light-years across. (NGC 2264 shown; see also the )
Planetary Nebulae
Planetary nebulae are shells of gas thrown out by some stars near the end of their lives. Our will probably produce a planetary nebula in about 5 billion years. They have nothing at all to do with ; the terminology was invented because they often look a little like planets in small telescopes. A typical planetary nebula is less than one light-year across. ( shown)
Supernova Remnants
Supernovae occur when a massive star ends its life in an amazing blaze of glory. For a few days a supernova emits as much energy as a whole galaxy. When it's all over, a large fraction of the star is blown into space as a supernova remnant. A typical supernova remnant is at most few light-years across. ( shown)
