"but in globular clusters the stellar density could be from 100 to 1000 per cubic parsec. Parsec The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System. A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond, which corresponds to astronomical units. One parsec is equal to about 3.26 light-years (30 trillion km or 19 trillion miles) in length. The nearest star, Proxima Centauri, is about from the Sun. Most of the stars visible to the unaided eye in the night"
"year as our galaxy, but they were much smaller and less massive, making it ""intensely star forming"". The light travel distance of the light that we observe from UDFy-38135539 (HUF.YD3) is more than 4 billion parsecs (13.1 billion light years), and it has a luminosity distance of 86.9 billion parsecs (about 283 billion light years). There are a number of different distance measures in cosmology, and both ""light travel distance"" and ""luminosity distance"" are different from the comoving distance or ""proper distance"" generally used in defining the size of the observable universe (comoving distance and proper distance are defined to"
"Light-second The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly metres by the definition of metre (just over miles). Just as the second forms the basis for other units of time, the light-second can form the basis for other units of length, ranging from the light-nanosecond (299.8 mm or just under one international foot) to the light-minute, light-hour and light-day, which are sometimes used in popular science publications. The more commonly used light-year is also"
"Light-second The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly metres by the definition of metre (just over miles). Just as the second forms the basis for other units of time, the light-second can form the basis for other units of length, ranging from the light-nanosecond (299.8 mm or just under one international foot) to the light-minute, light-hour and light-day, which are sometimes used in popular science publications. The more commonly used light-year is also"
"billion km or 670 astronomical units). To help compare different distances this section lists lengths starting at 10 m (1 Pm or 1 trillion km or 6685 astronomical units (AU) or 0.11 light years). To help compare different distances this section lists lengths starting at 10 m (10 Pm or 66,800 AU, 1.06 light years). To help compare different distances this section lists lengths between 10 m (100 Pm or 11 light years) and 10 m (106 light years). This list includes distances between 1 and 10 exametres (10 m). To help compare different distances this section lists lengths between"
"NGC 4026), UGC 6922 (26 arcminutes from NGC 4026) and UGC 6956 (10 arcminutes from NGC 4026). NGC 4026 appears disturbed in HI imaging, with a filament extending southward. The mass of HI in NGC 4026 is below 0.71 × 10 M⊙. The total HI mass in NGC 4026, UGC 6956 and the HI filament is estimated to be 7.94 × 10 M⊙. NGC 4026 NGC 4026 is a lenticular galaxy in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 4026 is"
"NGC 4026 NGC 4026 is a lenticular galaxy in the constellation Ursa Major. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 4026 is about 80,000 light years across. It was discovered by William Herschel on April 12, 1789. The galaxy hosts a supermassive black hole with estimated mass 10 (166-275 million) . NGC 4026 belongs to M109 Group, the largest subgroup of galaxies with the Ursa Major Cluster. In the vicinity of NGC 4026 lie some low surface brightness spiral galaxies, UGC 6917 (42 arcminutes from"
"than an arcsecond. The components are an object of apparent visual magnitude 5.5, γ Andromedae B, and a type-A main sequence star with apparent visual magnitude 6.3, γ Andromedae C. They have an orbital period of about 64 years. Spectrograms taken from 1957 to 1959 revealed that γ Andromedae B was itself a spectroscopic binary, composed of two type-B main sequence stars orbiting each other with a period of 2.67 days. was the name of United States navy ship. Gamma Andromedae Gamma Andromedae (γ Andromedae, abbreviated Gamma And, γ And) is the third-brightest point of light in the constellation of"
"the plane of the galactic disk. This system may be a member of the Ursa Major moving group. 26 Draconis 26 Draconis is a triple star system in the constellation Draco, located 46 light years from the Sun. Two of the system components, A and B, form a spectroscopic binary that completes an orbit every 76 years. The composite spectral classification of the AB pair is G0V, which decomposes to individual spectral types F9V and K3V. A 1962 study estimated the masses of these two stars as 1.30 and 0.83 times the mass of the Sun, respectively. The stars are"
"Metre The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit ""mètre"", from the Greek noun μέτρον, ""measure"") is the base unit of length in some metric systems, including the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in second. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is approximately 40,000 km today. In 1799, it was"
"distance measurement you use. With a redshift of 5.34, light from this galaxy is estimated to have taken around 12.5 billion years to reach us. But since this galaxy is receding from Earth, the present comoving distance is estimated to be around 26 billion light-years. RD1 RD1 or 0140+326 RD1 is a distant galaxy, it once held the title of most distant galaxy known. RD1 was discovered in March 1998, and is at ""z"" = 5.34, and was the first object found to exceed redshift 5. It bested the previous recordholders, a pair of galaxies at z=4.92 lensed by the"
"3C 66A 3C 66A is a blazar located in the constellation Andromeda. The ""distance"" of a far away galaxy depends on what distance measurement you use. With a redshift of 0.444, light from this active galaxy is estimated to have taken around 4.5 billion years to reach us. But as a result of the expansion of the Universe, the present (co-moving) distance to this galaxy is about 5.4 billion light-years (1647 Mpc). Even at this great distance this blazar has an apparent magnitude of about 15.5. Although 0.444 is used as the common redshift value, 0.3347 is a new strict"
"they appeared 13 billion years ago, when the universe was less than a billion years old. The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the evolution of stars, of galaxies, and of the universe itself. Astronomical distances are sometimes expressed in light-years, especially in popular science publications and media. A light-year is the distance light travels in one year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri,"
"Unit of length A unit of length refers to any discrete, pre-established length or distance having a constant magnitude which is used as a reference or convention to express linear dimension. The most common units in modern use are U.S. customary units in the United States and metric units elsewhere. British Imperial units are still used for some purposes in the United Kingdom and some other countries. The metric system is sub-divided into SI and non-SI units. The base unit in the International System of Units (SI) is the metre, defined as ""the length of the path travelled by light"
"the Sun of spectral type G5V and magnitude 6.18. The two are 10.6 astronomical units (au) apart and orbit each other every 21.78 years. The system is 52.4 ± 0.6 light-years distant from Earth. Likewise 16 Lyncis was originally known as Psi Aurigae and conversely, 37, 39, 41 and 44 Lyncis became part of Ursa Major. Y Lyncis is a popular target among amateur astronomers, as it is a semiregular variable ranging in brightness from magnitude 6.2 to 8.9. These shifts in brightness are complex, with a shorter period of 110 days due to the star's pulsations, and a longer"
"a star with a parallax angle of only one arcsecond measured on a baseline of one AU is a unit known as the parsec (pc) in astronomy and is equal to about 3.26 light years. There is an inverse relationship between the distance in parsecs and the angle in arcseconds. For instance, two arcseconds corresponds to a distance of and 0.5 arcsecond corresponds to a distance of two parsecs. The skinny triangle is useful in gunnery in that it allows a relationship to be calculated between the range and size of the target without the shooter needing to compute or"
"(symbol: pc, about 3.26 light-years; the distance at which one astronomical unit subtends an angle of one second of arc). As defined by the IAU, the light-year is the product of the Julian year (365.25 days as opposed to the 365.2425-day Gregorian year) and the speed of light (). Both of these values are included in the IAU (1976) System of Astronomical Constants, used since 1984. From this, the following conversions can be derived. The IAU recognized abbreviation for light-year is ly, although other standards like ISO 80000 use ""l.y."" and localized symbols are frequent, such as ""al"" in French"
"lunation. Such calendars include the Sumerian, Egyptian, Chinese, Babylonian, ancient Athenian, Buddhist, Hindu, Islamic, Icelandic, Mayan, and French Republican calendars. The modern calendar has its origins in the Roman calendar, which evolved into the Julian calendar, and then the Gregorian. Note: The light-year is not a unit of time, but a unit of length of about 9.5 trillion kilometres (9,454,254,955,488 kilometres). All of the important units of time can be interrelated. The key units are the second, defined in terms of an atomic process; the day, an integral multiple of seconds; and the year, usually 365 days (more info HERE)."
"speed, the old definition of the astronomical unit of length had the accepted value: 1 ua = ""c""τ = ± 3 m, where τ is the transit time of light across the astronomical unit. The astronomical unit of length was determined by the condition that the measured data in the ephemeris match observations, and that in turn decides the transit time τ. The distances to distant galaxies are typically not quoted in distance units at all, but rather in terms of redshift. The reasons for this are that converting redshift to distance requires knowledge of the Hubble constant which was"
"of magnitude, this section lists distances starting at 10 Zm (10 m or 1.1 million light years). To help compare different orders of magnitude, this section lists distances starting at 100 Zm (10 m or 11 million light years). The yottametre, or yottameter in the US, ( SI symbol: Ym) is a unit of length in the metric system equal to 10 metres To help compare different orders of magnitude, this section lists distances starting at 1 Ym (10 m or 105.702 million light years). To help compare different orders of magnitude, this section lists distances starting at 10 Ym"
"which was updated in 2000, including the IAU (1976) value cited above (truncated to 10 significant digits). Other high-precision values are not derived from a coherent IAU system. A value of found in some modern sources is the product of a mean Gregorian year (365.2425 days or ) and the defined speed of light (). Another value, , is the product of the J1900.0 mean tropical year and the defined speed of light. Abbreviations used for light years and multiples of light years are The light-year unit appeared a few years after the first successful measurement of the distance to"
"26 Draconis 26 Draconis is a triple star system in the constellation Draco, located 46 light years from the Sun. Two of the system components, A and B, form a spectroscopic binary that completes an orbit every 76 years. The composite spectral classification of the AB pair is G0V, which decomposes to individual spectral types F9V and K3V. A 1962 study estimated the masses of these two stars as 1.30 and 0.83 times the mass of the Sun, respectively. The stars are considered moderately metal-poor compared to the Sun, which means they have a lower proportion of elements other than"
"100 years × 365.25 days per year (0.25 is for a leap day every fourth year) × 24 hours per day × 3600 seconds per hour = 3,155,760,000 sec ≈ ""π"" sec × 10 within 0.45%. The speed of light is (by definition) exactly 299,792,458 m/s, very close to 300,000,000 m/s. This is a pure coincidence, as the meter was originally defined as 1/10,000,000 of the distance between the Earth's pole and equator along the surface at sea level, and the Earth's circumference just happens to be about 2/15 of a light-second. It is also roughly equal to one foot"
"Epsilon Normae Epsilon Normae, Latinised from ε Normae, is a blue-white hued triple star system in the southern constellation of Norma. It has an apparent visual magnitude of 4.47, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 6.15 mas as seen from Earth, the system is located around 530 light years distant from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.21 due to interstellar dust. The inner pair form a double-lined spectroscopic binary system with an orbital period of 3.26 days and"
"a star other than the Sun, by Friedrich Bessel in 1838. The star was 61 Cygni, and he used a heliometer designed by Joseph von Fraunhofer. The largest unit for expressing distances across space at that time was the astronomical unit, equal to the radius of the Earth's orbit or In those terms, trigonometric calculations based on 61 Cygni's parallax of 0.314 arcseconds, showed the distance to the star to be astronomical units ( or ). Bessel added that light employs 10.3 years to traverse this distance. He recognized that his readers would enjoy the mental picture of the approximate"
"for panels in accordance with SAE AS7788. Other units of luminance: Foot-lambert A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π candela per square foot, or 3.426 candela per square meter (the corresponding SI unit). The foot-lambert is named after Johann Heinrich Lambert (1728–1777), a Swiss-German mathematician, physicist and astronomer. It is rarely used by electrical and lighting engineers, in favor of the candela per square foot or candela per square meter. The luminance of a perfect Lambertian diffuse reflecting surface"
"2M 1237+6526 2MASS J12373919+6526148 (hereafter 2M 1237+6526) is a brown dwarf object with late spectral type T in the constellation of Draco, nearly 46 light years away from Sun. The substellar object could likely host a very low-mass companion (yet undetected but inferred), possibly in planetary regime. Burgasser et al. (2003) have inferred the presence of a low-mass companion orbiting the brown dwarf 2M 1237+6526. Such object would yield a mass between 3 and 12 times that of Jupiter and take nearly 4.56 hours (0.19 days) to revolve around its dim primary. If confirmed it would be the shortest period"
"Planck length In physics, the Planck length, denoted , is a unit of length that is the distance light travels in one unit of Planck time. It is equal to meters. It is a base unit in the system of Planck units, developed by physicist Max Planck. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constant. The Planck length is defined as: Solving the above will show the approximate equivalent value of this unit with respect to the meter: formula_2 where formula_3 is the"
"NGC 3726 NGC 3726 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 3726 is about 85,000 light years across. It was discovered by William Herschel οn February 5, 1788. NGC 3726 is a spiral galaxy with a small bar, seen with medium inclination. The bar is 1.38 arcseconds across and it ends at an inner ring with 1.50 arcseconds diametre. The bluest regions of star formation are located at the ring. Three arms emmanate from the"
"to be the only one of the companions physically associated, at the same distance and a projected separation of 750 AU. It has been added to the WDS as component D. Upsilon Andromedae A is a yellow-white dwarf of spectral type F8V, similar to the Sun, but younger, more massive, and more luminous. According to its entry in the Geneva–Copenhagen survey, the star is around 3.1 billion years old and has a similar proportion of iron relative to hydrogen to the Sun. At around 1.3 solar masses, it will have a shorter lifetime than the Sun. The amount of ultraviolet"
"NGC 3626 NGC 3626, also Caldwell 40, is a medium-tightness spiral galaxy and Caldwell object in the constellation Leo. It was discovered by William Herschel, on 14 March 1784. It shines at magnitude +10.6/+10.9. Its celestial coordinates are RA , dec . It is located near the naked-eye class A4 star Zosma, as well as galaxies NGC 3608, NGC 3607, NGC 3659, NGC 3686, NGC 3684, NGC 3691, NGC 3681, and NGC 3655. Its dimensions are 2′.7 × 1′.9. The galaxy belongs to the NGC 3607 group some 70 million light-years distant, itself one of the many Leo II groups."
"NGC 3626 NGC 3626, also Caldwell 40, is a medium-tightness spiral galaxy and Caldwell object in the constellation Leo. It was discovered by William Herschel, on 14 March 1784. It shines at magnitude +10.6/+10.9. Its celestial coordinates are RA , dec . It is located near the naked-eye class A4 star Zosma, as well as galaxies NGC 3608, NGC 3607, NGC 3659, NGC 3686, NGC 3684, NGC 3691, NGC 3681, and NGC 3655. Its dimensions are 2′.7 × 1′.9. The galaxy belongs to the NGC 3607 group some 70 million light-years distant, itself one of the many Leo II groups."
"by the European Space Agency for the Hipparcos Star Catalogue, Lambda Muscae exhibits a parallax of 25.42 milliarcseconds. With this data it can be calculated that Lambda Muscae is situated at a distance of 39.3 parsecs, or 128.0 light years, away from the sun. Lambda Muscae is a star of the third magnitude (or 3.68(v) to be exact) when viewed from the Earth, and is visible to the naked eye in regions that lack dense light pollution. Lambda Muscae is the farthest right star in the visual constellation of Musca and is thus the tail of the fly. Lambda Muscae"