ⓘ Free online encyclopedia. Did you know? page 395




                                               

Corvus (constellation)

Corvus is a small constellation in the southern sky. Its name is Latin for raven or crow. It has only 11 stars that can be seen without a telescope. It was one of the 48 constellations listed by Ptolemy. However, he only included 7 stars. Corvus ...

                                               

Leo (constellation)

Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is. Leo lies between dim Cancer to the west and Virgo to the east.

                                               

Lepus (constellation)

Lepus is a constellation south of the celestial equator. Its name is Latin for hare. The hare is not from any figure in Greek mythology. Lepus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy. It is one of the 88 mode ...

                                               

Monoceros

Monoceros is a constellation on the celestial equator. Its name is Greek for unicorn. It was described by 17th-century Dutch cartographer Petrus Plancius. Orion is to the west of Monceros. Gemini is to the north. Canis Major is to the south. Hydr ...

                                               

Orion (constellation)

Orion is one of the largest constellations in the sky. It is supposed to look like the warrior Orion from Greek mythology. The constellation has other names in different cultures: it is mentioned under a Hebrew name in the Book of Job. The conste ...

                                               

Ursa Major

Ursa Major is a constellation that can be seen in the northern hemisphere and part of the southern hemisphere. Its name means Great Bear in Latin. It was named that because many different groups of people around the world have thought that its st ...

                                               

Ursa Minor

Ursa Minor is a constellation in the northern sky. It is often called the Little Bear or the Little Dipper. Just like the related constellation Ursa Major, or the Big Bear or Big Dipper, it seems to have a long handle leading to a cup or ladle. T ...

                                               

Virgo (constellation)

Virgo is a zodiac constellation which lies on the celestial equator. It is between Leo and Libra.This constellation is large; the constellation is the second biggest constellation you can see on the sky. Legends say Virgo is Astraea.

                                               

Active galactic nucleus

An active galactic nucleus is a compact region at the centre of a galaxy. This central region radiates huge luminosity over the electromagnetic spectrum. The radiation from an AGN is thought to be caused by mass dragged in by the gravitational pu ...

                                               

Age of the universe

In cosmology, the age of the universe is the amount of time since the Big Bang. The best measurement of the age of the Universe is 13.8 billion years. The most recent and most accurate measurements were made by the Planck spacecraft. These measur ...

                                               

Comoving distance

In normal cosmology, comoving distance or proper distance is one of several distances measured by cosmologists to define distances between objects.

                                               

Cosmic microwave background radiation

Cosmic microwave background radiation is radiation in the microwave part of the electromagnetic spectrum, which comes from all directions in outer space. It is known to come from our earliest infant universe. Since the universe is very large, and ...

                                               

Cosmological principle

In modern physical cosmology, the cosmological principle is a prediction based on the idea that the universe is about the same in all places when viewed on a large scale. Forces are expected to act uniformly throughout the universe. There should, ...

                                               

Fecund universes

Fecund universes is a multiverse theory of Lee Smolin. It relies on models of our universe and statistics from astrophysics but is more correctly a theory of cosmology. In this theory, collapsing stars, or black holes, are always creating new uni ...

                                               

Fine-tuned universe

A universe that is fine-tuned is a universe that is designed well-enough to support life. Life as we know it would be impossible if certain things in physics were slightly different. Our universe is fine-tuned for life, and this is seen as not li ...

                                               

Edwin Hubble

Edwin Powell Hubble was an American astronomer. Hubbles findings changed the scientific view of the universe. In 1925 he showed that there are galaxies beyond our own, the Milky Way. Also, he developed a method for classifying galaxies. Then he p ...

                                               

Planck epoch

The Planck epoch is the earliest period of time in the history of the universe, before the time passed was equal to the Planck time ; that is from zero to approximately 10⁻⁴³ seconds. The Planck scale is the physical scale beyond which current ph ...

                                               

Red shift

Red shift is a way astronomers use to tell the distance of any object that is very far away in the Universe. The red shift is one example of the Doppler effect. The easiest way to experience the Doppler effect is to listen to a moving train. As t ...

                                               

Supersymmetry

Supersymmetry is a scientific theory that says that when elementary particles were formed at the beginning of the universe, matching kinds of theoretical "superparticles" were also created. If this theory is true, it would at least double the kin ...

                                               

White hole

A white hole is a hypothetical region in spacetime. It has not been proved to exist. It is said to be the exact opposite of a black hole. While a black hole sucks in objects to its singularity, the white hole emits matter from its singularity. A ...

                                               

Astronomical unit

The astronomical unit is a unit of length derived from the Earths orbit. It is the average distance the Earth gets from the Sun on the long axis of the ellipse. Its definition is: the length of the semi-major axis of the Earths elliptical orbit a ...

                                               

Cosmic distance ladder

The cosmic distance ladder is the way astronomers measure the distance of objects in space. No one method works for all objects and distances, so astronomers use a number of methods. A real direct distance measurement of an astronomical object is ...

                                               

National Astronomical Observatory of Japan

National Astronomical Observatory of Japan, also known as NAOJ, is a Japanese astronomy research organization. NAOJ has several facilities in Japan; and it has an observatory on Mauna Kea in Hawaii.

                                               

Blue shift

Blue shift is one example of the Doppler effect. It is the opposite effect to redshift. Doppler blueshift is caused by movement of a source towards the observer. The term applies to any decrease in wavelength caused by relative motion, even outsi ...

                                               

Gamma-ray burst

Gamma-ray bursts are flashes of gamma rays from extremely energetic explosions. They have been seen in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from milliseconds to severa ...

                                               

Luminous red nova

A luminous red nova is an explosion in space. It is probably caused when two stars merge to become one. Their red colour is distinctive. The light curve near the star stays in the infared. Luminous red novae are different from normal novae. Those ...

                                               

Proper motion

Proper motion is the name for the way the stars seem to slowly move relative to each other when seen from Earth. The movement is caused by the fact that all stars including the Sun are moving through space at hundreds of kilometres per second. Ho ...

                                               

Solstice

A solstice is an astronomical event that happens twice each year when the Sun reaches its highest position in the sky as seen from the North or South Pole. The day of the solstice is either the "longest day of the year" or the "shortest day of th ...

                                               

Summer solstice

The summer solstice is when the Sun is at its highest point in the sky during a year. The solstice itself is one moment, but many use the word to mean the day when the solstice happens. The summer solstice does not always happen on exactly the sa ...

                                               

Large-scale structure of the Universe

Large-scale structure of the Universe refers to the patterns of galaxies and matter on scales much large than individual galaxies and groupings of galaxies. These correlated structures can be seen up to billion of light years in length and are cr ...

                                               

Observable universe

In Big Bang cosmology, the observable universe is what, in theory, can be seen from Earth. That is light, or other signals, which has had time to reach the Earth since the beginning of the cosmological expansion. The observable universe is a sphe ...

                                               

Anatomy

Anatomy is the study of the bodies of people and other animals. Anatomy is the study of the inside of the body and outside the body. Anatomy notes the position and structure of organs such as muscles, glands and bones. A person who studies anatom ...

                                               

Allometry

Allometry is the study of the relationship of body size to shape. In particular, it refers to the rate of growth of one part of the body compared to other parts. In most cases, the relative size of body parts changes as the body grows. Most allom ...

                                               

Bipedalism

Bipedalism is a form of movement on the ground. Some tetrapods have evolved the ability to move on two limbs. Those that do, use their rear limbs. Some animals move on two limbs all the time, they are called habitual bipeds. Optional bipeds can m ...

                                               

Body cavity

Many animals have spaces or compartments in their body. These spaces or compartments are called body cavity. They are there for organs, or other structures. Sometimes, there is a space between two organs. This space is known as potential body cav ...

                                               

Histology

Histology is the study of the microscopic anatomy of cells and tissues of plants and animals, particularly the tissues. It is a part of cytology, and an essential tool of biology and medicine. Histology is usually done by looking at cells and tis ...

                                               

Human body

The human body is the body of a person. It is the physical structure of a person. The body is a thing that can be hurt or killed. Its functions are stopped by death. You need your muscles and your joints to move.

                                               

Morphology (biology)

For other uses, see Morphology disambiguation. Morphology is the study of animal or human form or body shape. It is the branch of biology dealing with the study of the form of organisms and their specific structural features. The concept of morph ...

                                               

Biochemistry

Biochemistry is the study of chemical reactions in living beings, and of biological molecules in general. It is important to cell biology and physiology. The study of biochemistry involves enzymes, nucleic acids, carbohydrates, sugars, proteins, ...

                                               

Affinity chromatography

Affinity chromatography is one way scientists separate molecules from each other. Using affinity chromatography, they can take just one kind of molecule out of a mixture of many molecules. Affinity chromatography works on molecules that exist ins ...

                                               

Agonist

An agonist is a type of chemical known as a ligand. It binds to a receptor. It activates the receptor to produce a response. An agonist causes an action. There are also antagonists which block the action of the agonists, and there are inverse ago ...

                                               

Bioinorganic chemistry

Bioinorganic chemistry studies the role of metals in biology. It also studies natural phenomena such as the behaviour of metalloproteins and artificially introduced metals in medicine and toxicology. Many biological processes such as respiration ...

                                               

Bioluminescence

Bioluminescence is the capacity of living things to produce light. Often this is done by symbiosis. In this, the larger organism contains, often in a special organ, microorganisms which make the light. Eukaryote protists have special organelles, ...

                                               

Bioorganic chemistry

Bioorganic chemistry is a science that combines organic chemistry and biochemistry. Bioorganic chemistry expands organic chemistry towards biology. This differs from biochemistry, which studies biological processes using chemistry. When investiga ...

                                               

Blood type

Blood type or blood group is a medical term. It describes the type of blood a person has. It is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells. Blood types predict wh ...

                                               

Carbon dioxide

Carbon dioxide is a chemical compound. It is a gas at room temperature. It is made of one carbon and two oxygen atoms. People and animals release carbon dioxide when they breathe out. Also, every time something organic is burnt, it makes carbon d ...

                                               

Cellophane

Cellophane is a bioplastic wrapping material. It is a thin, transparent sheet made of cellulose. It has low permeability. That means very little air, oils, greases, bacteria, and water can get in. That makes it useful for food packaging. Cellopha ...

                                               

Cellulose

Cellulose is the main chemical that forms the main structure of plants. It is the most abundant macromolecule on Earth. It is also a kind of fiber. Cellulose is a very complex carbohydrate and consisting of 3.000 or more glucose units. Cellulose ...

                                               

Creatine

Creatine is a combination of three non-essential amino acids. These are methionine, arginine and glycine. Creatine is used to produce adenosine triphosphate. The short word for Adenosine triphosphate is ATP. ATP is the energy of the human body. C ...

                                               

Cytosol

The cytosol or cytoplasmic matrix, or groundplasm) is the internal fluid of the cell, and a part of cell metabolism occurs here. Proteins within the cytosol play an important role in signal transduction pathways and glycolysis. Cytosol mostly con ...