Astronomy Oddities 2

 

Cow, The.  SN 2018cow, also known as “The Cow,” is a very powerful astronomical explosion.  It is the flattest explosion ever detected, flat as a pancake, rather than a sphere.  It is about 100 times brighter than a normal supernova.  It is the first example of a rare phenomenon called a fast blue optical transient (FBOT).  The shape of the blast is around the size of the solar system and occurred 180 million light-years away.    [source: Lea, “Extremely flat cosmic explosion dubbed ‘the Cow’ defies explanation,” space.com, April 3, 2023]

Gaia 17bbb.  The star Gaia 17bbb has been gradually increasing in luminosity over a 2.5 year period.  This is an unusually brightening star that has been behaving strangely.   From observations, the star has a strange companion responsible for the phenomenon, and not from the star.  The star is part of an exceptionally rare type of binary system between Gaia17bbb, a large, puffy older star, and a small companion star that is surrounded by an expansive disk of dusty material.  They orbit each other over an exceptionally long period of time – as much as 1,000 years. [source: Strickland, “Unusually brightening star captures attention as a stellar oddity,” cnn.com, Jan 12, 2023]

Gaia BH1 and Gaia BH2.  Two new black holes, Gaia BH1 and Gaia Bh2 are the closest ones to Earth known.  Gaia BH1 is 1,560 light-years away in the constellation Ophiuchus.  Gaia BH2 is 3,800 light-years away in the constellation Centaurus.  Both are obited by stars at uch greater distances than has been previouslt observed in other black hole-companion star pairings.   [Lea, “2 newfound black holes are the closest ever to Earth and like nothing seen before,” space.com, April 4, 2023]

Gamma-ray Burst.  Gamma-ray bursts (GRBs) are the strongest and brightest electromagnetic events (explosions) known to occur in the universe.  They are extremely energetic explosions that can last from 10 milliseconds to several hours.  GRBs are thought to be released during a supernova (exploding star) and the formation of a black hole.  The release of energy in a few seconds of an exploding supernova is roughly equal to that produced by the sun in its entire 10-billion-year lifetime.  The short burst GRBs appear to originate from the merger of binary neutron stars.  The first GRB was accidently discovered in 1967, when an Air Force satellite called Vela spotted one.  Vela was designed to watch for nuclear explosions on earth, but ended up finding gamma-rays coming from beyond the solar system (about 3 billion light-years away).[source: Mann, “What Is a Gamma-Ray Burst?” space.com, Jan 15, 2020]  On October 9, 2022, the brightest GRB ever observed, GRB 221009A, swept through our solar system.  The gamma-ray emission lasted over 300 seconds.  Astronomers think this was a birth cry of a black hole.  [source: Harvard-Smithsonian Center for Astrophysics, Mar 28, 2023]

Ganymede.  Ganymede is a moon of Jupiter and the largest moon in the Solar system.  It is the only moon to have a magnetic field.  The snapping and reconnecting of Ganymede’s magnetic field with Jupiter’s creates magnetospheric fireworks.  It has an internal ocean that may contain more water than all of Earth’s oceans combined.  [source: Southwest Research Institute, “Scientists find evidence for magnetic reconnection between Ganymede and Jupiter,” phys.org, Jan 10, 2023]

GLASS-z12.  GLASS-z12 is a Lyman-break galaxy discovered in July 2022.  It is one of the earliest and most distant galaxies ever discovered, dating back to just 350 million years after the Big Bang.  It existed around 13.5 billion years ago.  It has a redshift of z-12.4.  [source: Lea, “The most extreme celestial objects in the universe,” astronomy.com, Oct 10, 2022]

Globular Clusters.  Large groupings of tightly packed stars are called globular clusters.  There are more than 150 globular clusters in the Milky Way galaxy.  These clusters contain 100,000 to 1 million stars.  Inside the globular clusters can be found the oldest known stars in the Milky Way.  Also found in these groups are the unusual blue star stragglers.  These stars are hot, young stars that are large and bright.  No one knows how globular clusters formed.   [source: Briggs & Voices, “What is a globular cluster?,” EarthSky, Aug 14, 2022]

Gravitational Lensing.  A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known as gravitational lensing.  Gravitational lensing is a literal warping of spacetime.  It also has a magnifying effect, which makes it helpful for astronomers studying distant galaxies that may otherwise be too difficult to spot.  Gravitational lensing has allowed the James Webb Space Telescope see galaxy clusters around 6.3 billion light-years away.  [source: Getahun, “New James Webb telescope photo of a galaxy cluster 6 billion light years away shows a trippy phenomenon where gravity warps spacetime,” businessinsider.com, April 2, 2023]

Gravitational Wave.  Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light.  The first indirect evidence of gravitational waves came in 1974 from the observed orbital decay of a neutron star and a pulsar.  In 2015, the first direct observation of gravitational waves came when a signal was generated by the merger of two black holes.  In 2019, a bright Fast Radio Burst (FRB) was detected coming from a source 520 million light-years away.  About the same time, a gravitational wave event was detected from roughly the same direction.  Two orbiting neutron stars collided and merged.  The speed of gravitational waves is the speed of light.  [source: Ward, “Mysterious Radio Signal Follows Gravitational Waves Like Cosmic Thunder and Lightning,” syfy.com, April 2, 2023]

Hawking Radiation.  Hawking radiation is theoretical black body radiation that is released outside a black hole’s event horizon.  The Hawking radiation may be able to carry information.  This information may lurk in the radiation around black holes, called quantum hair, and could be retrieved to retell the origins of these black holes.  According to Stephen Hawking's work, radiation slowly "leaks" out of black holes in the form of thermal energy, called "Hawking radiation." But because of its thermal nature, this radiation can't carry information. That means that as black holes evaporate, they methodically destroy all information about the stars that created them. This is contrary to the laws of quantum mechanics, which say that information cannot be destroyed and that an object's final state can reveal clues about its initial state. This problem has troubled cosmologists for decades and is known as the "Hawking information paradox."   [source: Lea, “Stephen Hawking’s famous black hole paradox may finally have a solution.” space.com, April 4, 2023] 

HD 139139.  HD 139139 (also known as EPIC 249706694) is a sun-like star about 350 light-years away.  This odd star was observed by the Kepler space telescope to have 28 dips in its light, each of which lasted between 45 minutes and 7.5 hours.  The random dips do not appear to be periodic as would be expected if they were due to transiting planets.  The first explanation was that this star had as many and 28 planets revolving around it.  It also may be due to dust-emitting asteroids or short-lived star spots.  It is likely that this is a bound pair of stars, a little larger and brighter than our sun.  [source, Starr, “Astronomers Found a Star That Dims So Erratically, They Have No Explanation For It,” Science Alert, Jul 2, 2019]

HD 2047496b.  HD 2047496b (TOI-1099b) is a distant mini-Neptune, 77 light-years away, that may possess its own atmosphere, ocean, or a combination of the two, even if they don't last for long.  It will end up either as a rocky core covered by oceans, or as a barren naked planetary core.  The planet is less dense than the Earth and a width over two times that of Earth.  Its mass is about 6.1 times that of Earth.  It orbits its star every 6.4 Earth days. At about 5.8 million miles from its star.    [source: Lea, “Newly discovered ‘mini-Neptune may have an ocean or an atmosphere – but not for long,” space.com, March 15, 2023]

Hubble Constant.  The Hubble constant is the constant of proportionality in the relations between the velocities of remote galaxies and their distance.  It expresses the rate at which the universe is expanding.  The direct measurement of the Hubble constant is one of the biggest questions in contemporary cosmology.  As measurements have become more precise, a significant uncertainty in the Hubble constant measurement have emerged due to the discrepancy of the value from late (gravitational waves) and early (cosmic microwave background) universe measurements. [source: Bulla et al, “Multi-messenger constraints on the Hubble constant,” Astrobites.org, March 29, 2023]

Hyperion.  Hyperion is a moon of Saturn.  It is distinguished by its irregular shape and its chaotic rotation.  It has an unexplained sponge-like appearance  It is the first non-round moon to be discovered.  It rotates in a way that is much different from the rotation of any other moon in the Solar System.  It tumbles in its orbit.  The interior may house a vast system of caverns.

Iapetus.  Iapetus is a moon of Saturn, which has 83 known moons.  It was discovered in 1671 by Giovanni Cassini and was only visible for a few months out of the year, due to being tidally locked to Saturn.  It is the 3^rd largest moon of Saturn.  It is about the size of Australia and is walnut-shaped.  It has a severely inclined orbit and travels much further out than the other large moons.

Initial Mass Function.  The initial mass function (IMF) is an empirical function that describes the initial distribution of masses for a population of stars during star formation.  IMF not only describes the formation and evolution of individual stars, it also serves as an important link that describes the formation and evolution of galaxies.  The fate of galaxies is determined by the INF at the birth of a new population of stars.  The IMF is often given as a probability density function (PDF) that describes the probability of a star that has a certain mass.   IMF is derived from the luminosity function.  For years, astronomers believed that the IMF is a universal relationship and were consistent throughout the Universe.  Recent direct evidence shows how the IMF varies with different environments. If the IMF is variable, this could change the total mass estimates of galaxies and potentially alter the field of Galactic astronomy   [source: Chinese Academy of Science, “Unlocking the Mystery of the Stellar Initial Mass Function: A New Breakthrough Discovery,” SciTechDaily, Feb 8, 2023]

Inflation.  Cosmological inflation is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from 10⁻³⁶ seconds to between 10⁻³³ and 10⁻³² seconds after the Big Bang. Following the inflationary period, the universe continued to expand, but at a slower rate. The acceleration of this expansion due to dark energy began after the universe was already over 7.7 billion years old.   Inflation explains why the universe appears to be the same in all directions, why the cosmic microwave background radiation is distributed evenly, why the universe is flat, and why no magnetic monopoles have been observed. 

Intercluster Light.  Intercluster light (ICL) is a faint diffuse stellar component of cluster made of stars that are not bound to individual galaxies.  There are rogue stars that are not gravitationally bound to any particular galaxy within the cluster.  Their origin has yet to be found.  The first ICL was discovered in 1951.  These rogue stars may have originated in a galaxy, but was expelled as the result of either galaxies colliding or traveling too close to a black hole.

Interstellar Space.  Interstellar space is the physical space within a galaxy beyond the influence each star has upon the encompassed plasma. The contents of interstellar space are called the interstellar medium (ISM). Approximately 70% of the mass of the interstellar medium consists of lone hydrogen atoms; most of the remainder consists of helium atoms (less than 8%). This is enriched with trace amounts of heavier atoms formed through stellar nucleosynthesis. These atoms are ejected into the interstellar medium by stellar winds or when evolved stars begin to shed their outer envelopes such as during the formation of a planetary nebula.   It contains vast quantities of neutrinos, charged particles, atoms, molecules, dark matter and photons ranging from the highest-energy radiation to the sluggish light of the cosmic microwave background (CMB) albeit rather sparsely spread out.  The explosion of a supernova generates an expanding shock wave consisting of ejected materials that further enrich the medium.  The average distance between stars in the Milky Way galaxy is about 5 light-years. The solar wind starts to weaken as it comes up against interstellar space and slows down to 62 mph in interstellar space.  Stellar wind stops around 11 billion miles from the sun.   [source: Cooper, Interstellar space: What is it and where does it begin?,” space.com, Jan 17, 2023] 

Io.  Jupiter’s moon Io has over 400 active volcanoes and is considered the most active moon in the solar system.  It is the innermost and third-largest of Jupiter’s moons.  It is slightly larger than Earth’s moon.  It has the highest density of any moon and the strongest surface gravity of any moon.  It was discovered in 1610 by Galileo.  Several volcanoes produce plumes of sulfur as high as 300 miles above the surface.  Io’s volcanoes emit a ton of gases and particles into the space near Jupiter each second.  Io has over 100 mountains with some peaks higher than Mount Everest.

Jupiter’s Moons.  There are now 95 moons of Jupiter as of March, 2023.  12 new moons were discovered in 2022, to make the total of 92.  Three more moons were discovered in February, 2023, making a total of 95 moons.  Saturn has 83 moons, Uranus has 27 moons, and Neptune has 14 moons.   [source: Strickland, “Jupiter now has 92 moons after new discovery,” waow.com, Feb 7, 2023]