OrbitalHub

NASA dicit:

NASA’s Dawn spacecraft captured pictures in visible and infrared wavelengths, which were combined to create this false-color view of a region in 57-mile-wide (92-kilometer-wide) Occator Crater on the dwarf planet Ceres (in the main asteroid belt between Mars and Jupiter). Here, recently exposed brine, or salty liquids, in the center of the crater were pushed up from a deep reservoir below Ceres’ crust. In this view, they appear reddish.

Seen here is Cerealia Facula (“facula” means bright area), a 9-mile-wide (15-kilometer-wide) region with a composition dominated by salts. The central dome, Cerealia Tholus, is about 1.9 miles (3 kilometers) across at its base and 1,100 feet (340 meters) tall. The dome is inside a central depression about 3,000 feet (900 meters) deep.

Dawn’s mission is managed by NASA’s Jet Propulsion Laboratory, a division of Caltech, for the agency’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Northrop Grumman in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

Video credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

NASA dicit:

Scientists using NASA’s telescope on an airplane, the Stratospheric Observatory for Infrared Astronomy, discovered water on a sunlit surface of the Moon for the first time. SOFIA is a modified Boeing 747SP aircraft that allows astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes. Molecular water, H2O, was found in Clavius Crater, one of the largest craters visible from Earth in the Moon’s southern hemisphere. This discovery indicates that water may be distributed across the lunar surface, and not limited to cold, shadowed places.

Video credit: NASA’s Ames Research Center

Wikipedia dicit:

Dark matter is hypothesized to be a form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total mass–energy density or about 2.241×10−27 kg/m3. Support for its presence is drawn from a variety of astrophysical observations, including gravitational effects that under current theories of gravity do not make sense, unless more matter is present than can be seen. For this reason, the hypothesis has been created that dark matter exists, is abundant in the universe, and has had a strong influence on its structure and evolution. The name is due to the fact that by all observations, should dark matter exist, it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect or emit electromagnetic radiation, and is therefore difficult to detect.

Primary support for dark matter comes from calculations showing that many galaxies would fly apart, or that they would not have formed or would not move as they do, if they did not contain a large amount of unseen matter. Other lines of evidence include observations in gravitational lensing and in the cosmic microwave background, along with astronomical observations of the observable universe’s current structure, the formation and evolution of galaxies, mass location during galactic collisions, and the motion of galaxies within galaxy clusters. In the standard Lambda-CDM model of cosmology, the total mass–energy of the universe contains 5% ordinary matter and energy, 27% dark matter and 68% of a form of energy known as dark energy. Thus, dark matter constitutes 85% of total mass, while dark energy plus dark matter constitute 95% of total mass–energy content.

Because dark matter has not yet been observed directly, if it exists, it must barely interact with ordinary baryonic matter and radiation, except through gravity. Most dark matter is thought to be non-baryonic in nature; it may be composed of some as-yet undiscovered subatomic particles. The primary candidate for dark matter is some new kind of elementary particle that has not yet been discovered, in particular, weakly interacting massive particles (WIMPs). Many experiments to directly detect and study dark matter particles are being actively undertaken, but none have yet succeeded. Dark matter is classified as “cold”, “warm”, or “hot” according to its velocity (more precisely, its free streaming length). Current models favor a cold dark matter scenario, in which structures emerge by gradual accumulation of particles.

Video credit: NASA’s Goddard Space Flight Center/Paul Morris (USRA): Lead Producer/Cassandra Morris: Voice over Talent/Visualizations and Additional Footage: ESA/Hubble — Gravitational Lensing Animation/ESA/Hubble — Gravitational Lensing Simplified Visualization/R. Wesson/ESO — Very Large Telescope Footage

NASA dicit:

In pursuit of understanding why the Sun’s atmosphere is so much hotter than the surface, and to help differentiate between a host of theories about what causes this heating, researchers turn to NASA’s Interface Region Imaging Spectrograph (IRIS) mission. IRIS was finely tuned with a high-resolution imager to zoom in on specific hard-to-see events on the Sun.

A paper published in Nature on September 21, 2020, reports on the first ever clear images of nanojets — bright, thin lights that travel perpendicular to magnetic structures in the solar atmosphere called the corona — in a process that reveals the existence of one of the potential coronal heating candidates: nanoflares.

Video credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio/Scientist: Patrick Antolin (Northumbria University)/Data Visualizer: Tom Bridgman (GST)/Producer: Joy Ng (USRA)/Writer: Susannah Darling (ADNET)

NASA dicit:

The Sun is stirring from its latest slumber. As sunspots and flares, signs of a new solar cycle, bubble from the Sun’s surface, scientists are anticipating a flurry of solar activity over the next few years. Roughly every 11 years, at the height of this cycle, the Sun’s magnetic poles flip — on Earth, that’d be like the North and South Poles’ swapping places every decade — and the Sun transitions from sluggish to active and stormy. At its quietest, the Sun is at solar minimum; during solar maximum, the Sun blazes with bright flares and solar eruptions. In this video, view the Sun’s disk from our space telescopes as it transitions from minimum to maximum in the solar cycle.

Video credit: NASA’s Goddard Space Flight Center/Joy Ng (USRA): Producer/Tom Bridgman (GST): Data Visualizer/Maria-Jose Vinas Garcia (Telophase): Support/Pedro Cota (ADNET Systems): Support

NASA dicit:

NASA’s Neil Gehrels Swift Observatory tallied the water lost from an interstellar comet as it approached and rounded the Sun. The object, 2I/Borisov, traveled through the solar system in late 2019.

Comets are frozen clumps of gases mixed with dust, often called “dirty snowballs.” As a one approaches the Sun, frozen material on its surface warms and converts to gas.

When sunlight breaks apart water molecules, one of the fragments is hydroxyl, a molecule composed of one oxygen and one hydrogen atom. Swift detects the fingerprint of ultraviolet light emitted by hydroxyl using its Ultraviolet/Optical Telescope (UVOT). Between September and February, Swift made six observations of Borisov with Swift. It saw a 50% increase in the amount of hydroxyl — and therefore water — Borisov produced between Nov. 1 and Dec. 1, which was just seven days from the comet’s closest brush with the Sun.

At peak activity, Borisov shed eight gallons (30 liters) of water per second, enough to fill a bathtub in about 10 seconds. During its trip through the solar system, the comet lost nearly 61 million gallons (230 million liters) of water — enough to fill over 92 Olympic-size swimming pools. As it moved away from the Sun, Borisov’s water loss dropped off — and did so more rapidly than any previously observed comet.

Swift’s water production measurements also helped show that Borisov’s minimum size is just under half a mile (0.74 kilometer) across. The team estimates at least 55% of Borisov’s surface was actively shedding material when it was closest to the Sun. That’s a large fraction compared to most observed solar system comets.

Video credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio/Scott Wiessinger (USRA): Lead Producer/Jeanette Kazmierczak (University of Maryland College Park): Lead Science Writer/Scott Wiessinger (USRA): Lead Animator/Dennis Bodewits (Auburn University): Scientist/Zexi Xing (University of Hong Kong): Scientist/Francis Reddy (University of Maryland College Park): Science Writer