OrbitalHub

NASA dicit:

Using NASA’s Neil Gehrels Swift Observatory, which launched in 2004, scientists have discovered a black hole in a distant galaxy repeatedly nibbling on a Sun-like star. The object heralds a new era of Swift science made possible by a novel method for analyzing data from the satellite’s X-ray Telescope (XRT). When a star strays too close to a monster black hole, gravitational forces create intense tides that break the star apart into a stream of gas. The leading edge swings around the black hole, and the trailing edge escapes the system. These destructive episodes are called tidal disruption events. Astronomers see them as flares of multiwavelength light created when the debris collides with a disk of material already orbiting the black hole.

Recently, astronomers have been investigating variations on this phenomena, which they call partial or repeating tidal disruptions. During these events, every time an orbiting star passes close to a black hole, the star bulges outward and sheds material, but survives. The process repeats until the star looses too much gas and finally breaks apart. The characteristics of the individual star and black hole system determine what kind of emission scientists observe, creating a wide array of behaviors to categorize.

On June 22, 2022, XRT captured Swift J0230 for the first time. It lit up in a galaxy around 500 million light-years away in the northern constellation Triangulum. Swift’s XRT has observed nine additional outbursts from the same location roughly every few weeks. Scientists propose that Swift J0230 is a repeating tidal disruption of a Sun-like star orbiting a black hole with over 200,000 times the Sun’s mass. They estimate the star loses around three Earth masses of material on each pass. This system provides a bridge between other types of suspected repeating disruptions and allowed scientists to model how interactions between different star types and black hole sizes affect what we observe.

Swift J0230’s discovery was possible thanks to a new, automated search of XRT observations called the Swift X-ray Transient Detector. After the instrument observes a portion of the sky, the data is transmitted to the ground, and the program compares it to previous XRT snapshots of the same spot. If that portion of the X-ray sky has changed, scientists get an alert. In the case of Swift J0230, astronomers were able to rapidly coordinate additional observations of the region.

Video credit: NASA’s Goddard Space Flight Center/Producer: Sophia Roberts (AIMM)/Science writer: Jeanette Kazmierczak (University of Maryland College Park)/Editor: Sophia Roberts (AIMM)/Narrator: Sophia Roberts (AIMM)/Animator: Chris Smith (KBRwyle)/Project support: Scott Wiessinger (KBRwyle)

NASA dicit:

New NASA and Durham University simulations put forth a theory of the origin of Saturn’s rings and icy moons – they may have formed following a massive collision between two moons orbiting the gas giant. The simulations used in this research are some of the most detailed of their kind to study the formation of Saturn’s rings and potentially habitable icy moons.

Video credit: NASA/Jacob Kegerreis/Luís Teodoro

NASA dicit:

The animation highlights the “super” in supermassive black holes. These monsters lurk in the centers of most big galaxies, including our own Milky Way, and contain between 100,000 and tens of billions of times more mass than our Sun.

Any light crossing the event horizon – the black hole’s point of no return – becomes trapped forever, and any light passing close to it is redirected by the black hole’s intense gravity. Together, these effects produce a “shadow” about twice the size of the black hole’s actual event horizon.

The animation shows 10 supersized black holes that occupy center stage in their host galaxies, including the Milky Way and M87, scaled by the sizes of their shadows. Starting near the Sun, the camera steadily pulls back to compare ever-larger black holes to different structures in our solar system.

First up is 1601+3113, a dwarf galaxy hosting a black hole packed with the mass of 100,000 Suns. The matter is so compressed that even the black hole’s shadow is smaller than our Sun.

The black hole at the heart of our own galaxy, called Sagittarius A* (pronounced ay-star), boasts the weight of 4.3 million Suns based on long-term tracking of stars in orbit around it. It’s shadow diameter spans about half that of Mercury’s orbit in our solar system.

The animation shows two monster black holes in the galaxy known as NGC 7727. Located about 1,600 light-years apart, one weighs 6 million solar masses and the other more than 150 million Suns. Astronomers say the pair will merge within the next 250 million years.

At the animation’s larger scale lies M87’s black hole, now with a updated mass of 5.4 billion Suns. Its shadow is so big that even a beam of light – traveling at 670 million mph (1 billion kph) – would take about two and a half days to cross it.

The movie ends with TON 618, one of a handful of extremely distant and massive black holes for which astronomers have direct measurements. This behemoth contains more than 60 billion solar masses, and it boasts a shadow so large that a beam of light would take weeks to traverse it.

Video credit: NASA Goddard

NASA dicit:

A new study using the now-retired Stratospheric Observatory for Infrared Astronomy (SOFIA) has pieced together the first detailed, wide-area map of water distribution on the Moon. The new map covers about one-quarter of the Earth-facing side of the lunar surface below 60 degrees latitude and extends to the Moon’s South Pole. In this data visualization, SOFIA’s lunar water observations are indicated using color, with blue representing areas of higher water signal, and brown lower.

Video credit: NASA’s Goddard Space Flight Center Scientific Visualization Studio/Ernie Wright

Wikipedia dicit:

Plasma (from Ancient Greek πλάσμα (plásma) ‘moldable substance’) is one of four fundamental states of matter, characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. It is the most abundant form of ordinary matter in the universe, being mostly associated with stars, including the Sun. Extending to the rarefied intracluster medium and possibly to intergalactic regions, plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field.

The presence of charged particles makes plasma electrically conductive, with the dynamics of individual particles and macroscopic plasma motion governed by collective electromagnetic fields and very sensitive to externally applied fields. The response of plasma to electromagnetic fields is used in many modern devices and technologies, such as plasma televisions or plasma etching.

Depending on temperature and density, a certain number of neutral particles may also be present, in which case plasma is called partially ionized. Neon signs and lightning are examples of partially ionized plasmas. Unlike the phase transitions between the other three states of matter, the transition to plasma is relatively not well defined and is a matter of interpretation and context. Whether a given degree of ionization suffices to call a substance ‘plasma’ depends on the specific phenomenon being considered.

Video credit: NASA’s Goddard Space Flight Center/Beth Anthony (KBRwyle): Producer/Mara Johnson-Groh (Telophase): Writer/Barbara Giles (NASA/GSFC): Scientist/Genna Duberstein (ADNET): Writer/Music: “Artificial Intelligence” by Matteo Pagamici [SUISA], Max Molling [SUISA] via Universal Production Music

Wikipedia dicit:

Concerning the lunar month of approximately 29.53 days as viewed from Earth, the lunar phase or Moon phase is the shape of the Moon’s directly sunlit portion, which can be expressed quantitatively using areas or angles, or described qualitatively using the terminology of the four major phases (new moon, first quarter, full moon, last quarter) and four minor phases (waxing crescent, waxing gibbous, waning gibbous, and waning crescent).

The lunar phases gradually change over a synodic month (c. 29.53 days) as the orbital positions of the Moon around Earth, and Earth around the Sun, shift. The visible side of the Moon is variously sunlit, depending on the position of the Moon in its orbit, with the sunlit portion varying from 0% (at new moon) to 100% (at full moon).

Each of the four major lunar phases is approximately 7.4 days±19 hours (6.58–8.24 days), the variation being due to the elliptical shape of the Moon’s orbit.

There are four principal (primary, or major) lunar phases: the new moon, first quarter, full moon, and last quarter (also known as third or final quarter), when the Moon’s ecliptic longitude is at an angle to the Sun (as viewed from the center of the Earth) of 0°, 90°, 180°, and 270° respectively. Each of these phases appears at slightly different times at different locations on Earth, and tabulated times are therefore always geocentric (calculated for the Earth’s center).

Between the principal phases are intermediate phases, during which the Moon’s apparent shape is either crescent or gibbous. On average, the intermediate phases last one-quarter of a synodic month, or 7.38 days.

The term waxing is used for an intermediate phase when the Moon’s apparent shape is thickening, from new to a full moon; and waning when the shape is thinning. The duration from full moon to new moon (or new moon to full moon) varies from approximately 13 days 22+1⁄2 hours to about 15 days 14+1⁄2 hours.

A new moon appears highest on the summer solstice and lowest on the winter solstice. A first quarter moon appears highest on the spring equinox and lowest on the autumn equinox. A full moon appears highest on the winter solstice and lowest on the summer solstice. A last quarter moon appears highest on the autumn equinox and lowest on the spring equinox.

Credit: NASA Goddard