The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy distanced 21 million light-years (six megaparsecs) away in the constellation Ursa Major, first discovered by Pierre MŽchain on March 27, 1781, and communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final entries. On February 28, 2006, NASA and...
The Milky Way, or simply the Galaxy, is the galaxy in which the Solar System is located. It is a barred spiral galaxy that is part of the Local Group of galaxies. It is one of billions of galaxies in the observable universe. Its name is a translation of the Latin Via Lactea, in turn translated from the Greek Galaxias), referring to the pale band of light formed by the galactic plane as seen from...
Hoag’s Object is a non-typical galaxy of the type known as a ring galaxy. The appearance of this object has interested amateur astronomers as much as its uncommon structure has fascinated professionals. The galaxy is named after Arthur Allen Hoag who discovered it in 1950 and identified it as either a planetary nebula or a peculiar galaxy with eight billion stars. A nearly perfect ring of...
Archaeology of a million stars to unravel galaxies’ evolution April 9, 2015 Our archaeology of space is a new era in astronomy and the knowledge gained promises to be every bit as exciting and important as anything discovered on Earth. Archaeology is no longer earthbound but is being used to solve one of the fundamental mysteries of astronomy. We still don’t understand how the more...
Blue Galaxies are small, distant galaxies, billions of light years away. We are therefore seeing them as they were when both they and the universe were quite young. You might think that, because the galaxies are so far away, their light would be so strongly red in appearance. Blue galaxies long ago were forming new stars, therefore most of their light was emitted in the blue and ultraviolet...
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter literally meaning “milky”, a reference to the Milky Way. Galaxies range in size from dwarfs with just a few billion stars to giants with one hundred trillion stars each orbiting its galaxy’s center of mass. Galaxies are categorized according to their visual morphology...
The flat Earth model is an archaic conception of Earth’s shape as a plane or disk. Many ancient cultures subscribed to a flat Earth cosmography, including Greece until the classical period, the Bronze Age and Iron Age civilizations of the Near East until the Hellenistic period, India until the Gupta period (early centuries AD), and China until the 17th century. The idea of a spherical Earth...
An extrasolar planet is a planet which orbits a star other than the Sun, i.e. which belongs to a planetary system other than our solar system. Extrasolar planets were discovered during the 1990s as a result of improved telescope technology, such as CCD and computer-based image processing along with the Hubble Space Telescope. Such advances allowed for more accurate measurements of stellar motion...
A lunar eclipse is an eclipse which occurs whenever the moon passes behind the earth such that the earth blocks the sun’s rays from striking the moon. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, there is always a full moon the night of a lunar eclipse. The type and length of an eclipse depend upon...
Full Moon, Full Earth NASA – August 7, 2015 The Moon was new on July 16. Its familiar nearside facing the surface of planet Earth was in shadow. But on that date a million miles away, the Deep Space Climate Observatory (DSCOVR) spacecraft’s Earth Polychromatic Imaging Camera (EPIC) captured this view of an apparently Full Moon crossing in front of a Full Earth. In fact, seen from the...