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3MM-1
3MM-1 (also known as COS-3mm-1) is a star-forming galaxy about 12.5 billion light-years away that is obscured by clouds of dust. It is located in the constellation of Sextans. It was first detected in spectroscopic data on rotational transitions of carbon monoxide obtained using the Atacama Large Millimeter Array from 23-24 December 2018, as detailed in an article that was published on 22 October 2019. The authors of this article described the discovery as "serendipitous", since the focus of their planned observations had been on galaxies at redshifts near 1.5 that are quiescent — i.e. do not form stars — and directly observable, yet 3MM-1 was found at a redshift of about 5.5, is forming stars and not directly observable. In the same dataset, another dust-obscured star-forming galaxy, 3MM-2, was found at a redshift of about 3.3. In early 2021, a more precise estimate of 3MM-1's redshift was published, according to which the value is z = 5.857 ± 0.001. 3MM-1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextans
Sextans is a minor celestial equator, equatorial constellation which was introduced in 1687 by Johannes Hevelius. Its name is Latin for the sextant (astronomical), astronomical sextant, an instrument that Hevelius made frequent use of in his observations. Notable features Sextans as a constellation covers a rather dim, sparse region of the sky. It has only one star above the apparent magnitude, fifth magnitude, namely Alpha Sextantis, α Sextantis at 4.49m. The constellation contains a few double stars, including Gamma Sextantis, γ, 35 Sextantis, 35, and 40 Sextantis. There are a few notable variable stars, including Beta Sextantis, β, 25 Sextantis, 25, 23 Sextantis, and LHS 292. NGC 3115, an edge-on lenticular galaxy, is the only noteworthy deep-sky object. It also lies near the ecliptic, which causes the Moon, and some of the planets to occasionally pass through it for brief periods of time. The constellation is the location of the field studied by the Cosmic Evolution Sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star-forming Galaxy
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang. The simplest model in general agreement with observed phenomena is the Lambda-CDM model—that is, that clustering and merging allows galaxies to accumulate mass, determining both their shape and structure. Commonly observed properties of galaxies Because of the inability to conduct experiments in outer space, the only way to “test” theories and models of galaxy evolution is to compare them with observations. Explanations for how galaxies formed and evolved must be able to predict the observed properties and types of galaxies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Dust
Cosmic dust, also called extraterrestrial dust, star dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 micrometers). Larger particles are called meteoroids. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust (such as in the zodiacal cloud) and circumplanetary dust (such as in a planetary ring). There are several methods to obtain space dust measurement. In the Solar System, interplanetary dust causes the zodiacal light. Solar System dust includes comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through the Solar System. Thousands of tons of cosmic dust are estimated to reach the Earth's surface every year, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Role Of Chance In Scientific Discoveries
The role of chance, or "luck", in science comprises all ways in which unexpected discoveries are made. Many domains, especially psychology, are concerned with the way science interacts with chance — particularly "serendipity" (accidents that, through sagacity, are transformed into opportunity). Psychologist Kevin Dunbar and colleagues estimate that between 30% and 50% of all scientific discoveries are accidental in some sense (see examples below). Psychologist Alan A. Baumeister says a scientist must be "sagacious" (attentive and clever) to benefit from an accident. Dunbar quotes Louis Pasteur's saying that "Chance favors only the prepared mind". The prepared mind, Dunbar suggests, is one trained for observational rigor. Dunbar adds that there is a great deal of writing about the role that serendipity ("happy accidents") plays in the scientific method.Dunbar, K., & Fugelsang, J. (2005). Causal thinking in science: How scientists and students interpret the unexpected. In M. E. G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a negative redshift, or blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. In astronomy and cosmology, the three main causes of electromagnetic redshift are # The radiation travels between objects which are moving apart (" relativistic" redshift, an example of the relativistic Doppler effect) #The radiation travels towards an object in a weaker gravitational potential, i.e. towards an object in less strongly curved (flatter) spacetime (gravitational redshift) #The radiation travels through expanding space (cosmological redshift). The observation that all sufficiently distant light sources show redshift corresponding to their distance from Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Mass
Stellar mass is a phrase that is used by astronomers to describe the mass of a star. It is usually enumerated in terms of the Sun's mass as a proportion of a solar mass (). Hence, the bright star Sirius has around . A star's mass will vary over its lifetime as mass is lost with the stellar wind or ejected via pulsational behavior, or if additional mass is accreted, such as from a companion star. Properties Stars are sometimes grouped by mass based upon their evolutionary behavior as they approach the end of their nuclear fusion lifetimes. ''Very-low-mass stars'' with masses below 0.5 do not enter the asymptotic giant branch (AGB) but evolve directly into white dwarfs. (At least in theory; the lifetimes of such stars are long enough—longer than the age of the universe to date—that none has yet had time to evolve to this point and be observed.) ''Low-mass stars'' with a mass below about 1.8–2.2 (depending on composition) do enter the AGB, where they develop a degenerate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Mass
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of the Sun. This equates to about two nonillion (short scale), two quintillion (long scale) kilograms or 2000 quettagrams: The solar mass is about times the mass of Earth (), or times the mass of Jupiter (). History of measurement The value of the gravitational constant was first derived from measurements that were made by Henry Cavendish in 1798 with a torsion balance. The value he obtained differs by only 1% from the modern value, but was not as precise. The diurnal parallax of the Sun was accurately measured during the transits of Venus in 1761 and 1769, yielding a value of (9 arcseconds, compared to the present value of ). From the value of the diurnal parallax, one can determine the distance to the Sun from the geometry o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term ''Milky Way'' is a translation of the Latin ', from the Greek ('), meaning "milky circle". From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with an estimated D25 isophotal diameter of , but only about 1,000 light years thick at the spiral arms (more at the bulg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
