OrbitalHub

Wikipedia dicit:

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter is one of the brightest objects visible to the naked eye in the night sky, and has been known to ancient civilizations since before recorded history. It is named after the Roman god Jupiter. When viewed from Earth, Jupiter can be bright enough for its reflected light to cast shadows, and is on average the third-brightest natural object in the night sky after the Moon and Venus.

Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, though helium comprises only about a tenth of the number of molecules. It may also have a rocky core of heavier elements, but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rapid rotation, the planet’s shape is that of an oblate spheroid (it has a slight but noticeable bulge around the equator). The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere. Jupiter has 79 known moons, including the four large Galilean moons discovered by Galileo Galilei in 1610. Ganymede, the largest of these, has a diameter greater than that of the planet Mercury.

Video credit: NASA Goddard

Wikipedia dicit:

2I/Borisov, originally designated C/2019 Q4 (Borisov), is the first observed interstellar comet and the second observed interstellar interloper after ʻOumuamua. 2I/Borisov has a heliocentric orbital eccentricity of 3.36 and is not bound to the Sun. The comet passed through the ecliptic of the Solar System at the end of October 2019, and made its closest approach to the Sun at just over 2 AU on 8 December 2019. In November 2019, astronomers from Yale University said that the comet (including coma and tail), was 14 times the size of Earth, and stated, “It’s humbling to realize how small Earth is next to this visitor from another solar system.” In the middle of March, 2020, the comet was observed to fragment; and later, in April, even more evidence of fragmentation was reported.

Video credit: NASA

NASA dicit:

Scheduled to launch in the mid-2020s, the Nancy Grace Roman Space Telescope, formerly known as WFIRST, will function as Hubble’s wide-eyed cousin. While just as sensitive as Hubble’s cameras, the Roman Space Telescope’s 300-megapixel Wide Field Instrument will image a sky area 100 times larger. This means a single Roman Space Telescope image will hold the equivalent detail of 100 pictures from Hubble.

The mission’s wide field of view will allow it to generate a never-before-seen big picture of the universe, which will help astronomers explore some of the greatest mysteries of the cosmos, like why the expansion of the universe seems to be accelerating. Some scientists attribute the speed-up to dark energy, an unexplained pressure that makes up 68% of the total content of the cosmos.

The Wide Field Instrument will also allow the Roman Space Telescope to measure the matter in hundreds of millions of distant galaxies through a phenomenon dictated by Einstein’s relativity theory. Massive objects like galaxies curve space-time in a way that bends light passing near them, creating a distorted, magnified view of far-off galaxies behind them. The Roman Space Telescope will paint a broad picture of how matter is structured throughout the universe, allowing scientists to put the governing physics of its assembly to the ultimate test.

The Roman Space Telescope can use this same light-bending phenomenon to study planets beyond our solar system, known as exoplanets. In a process called microlensing, a foreground star in our galaxy acts as the lens. When its motion randomly aligns with a distant background star, the lens magnifies, brightens and distorts the background star. The Roman Space Telescope’s microlensing survey will monitor 100 million stars for hundreds of days and is expected to find about 2,500 planets, well targeted at rocky planets in and beyond the region where liquid water may exist.

These results will make the Roman Space Telescope an ideal companion to missions like NASA’s Kepler and the upcoming Transiting Exoplanet Survey Satellite (TESS), which are designed to study larger planets orbiting closer to their host stars. Together, discoveries from these three missions will help complete the census of planets beyond our solar system. The combined data will also overlap in a critical area known as the habitable zone, the orbiting distance from a host star that would permit a planet’s surface to harbor liquid water — and potentially life.

By pioneering an array of innovative technologies, the Roman Space Telescope will serve as a multipurpose mission, formulating a big picture of the universe and helping us answer some of the most profound questions in astrophysics, such as how the universe evolved into what we see today, its ultimate fate and whether we are alone.

Video credit: NASA’s Goddard Space Flight Center
Scott Wiessinger (USRA): Lead Producer
Claire Andreoli (NASA/GSFC): Lead Public Affairs Officer
Barb Mattson (University of Maryland College Park): Narrator
Francis Reddy (University of Maryland College Park): Science Writer
Michael Lentz (USRA): Animator
Chris Meaney (KBRwyle): Animator
Adriana Manrique Gutierrez (USRA): Animator
Scott Wiessinger (USRA): Animator
Scott Wiessinger (USRA): Editor

Wikipedia dicit:

The Solar and Heliospheric Observatory (SOHO) is a spacecraft built by a European industrial consortium led by Matra Marconi Space (now Airbus Defence and Space) that was launched on a Lockheed Martin Atlas II AS launch vehicle on December 2, 1995 to study the Sun. SOHO has also discovered over 3,000 comets. It began normal operations in May 1996. It is a joint project of international cooperation between the European Space Agency (ESA) and NASA. Originally planned as a two-year mission, SOHO continues to operate after over 25 years in space: the mission is extended until the end of 2020 with a likely extension until 2022.

In addition to its scientific mission, it is a main source of near-real-time solar data for space weather prediction. Along with Wind, ACE and DSCOVR, SOHO is one of four spacecraft in the vicinity of the Earth–Sun L1 point, a point of gravitational balance located approximately 0.99 astronomical unit (AU)s from the Sun and 0.01 AU from the Earth. In addition to its scientific contributions, SOHO is distinguished by being the first three-axis-stabilized spacecraft to use its reaction wheels as a kind of virtual gyroscope; the technique was adopted after an on-board emergency in 1998 that nearly resulted in the loss of the spacecraft.

Video credit: NASA Goddard

Wikipedia dicit:

In 2019, NASA’s James Webb Space Telescope celebrated the full mechanical and electrical assembly of the world’s largest, most powerful space science observatory ever built. Webb’s two halves have been physically put together and its wiring harnesses and electrical interfaces have been connected.

Following assembly, the Webb team moved on to successfully send deployment and tensioning commands to all five layers of its sunshield, which is designed to protect the observatory’s mirrors and scientific instruments from light and heat, primarily from the Sun.

Ensuring mission success for an observatory of this scale and complexity is a challenging endeavor. All of the telescope’s major components have been tested individually through simulated environments they would encounter during launch, and while orbiting a million miles away from Earth. Now that Webb is fully assembled, it must meet rigorous observatory-level standards. The complete spacecraft reacts and performs differently to testing environments than when its components are tested individually.

Following Webb’s successful sunshield deployment and tensioning test, team members have nearly finished the long process of perfectly folding the sunshield back into its stowed position for flight, which occupies a much smaller space than when it is fully deployed. Then, the observatory will be subjected to comprehensive electrical tests and one more set of mechanical tests that emulate the launch acoustic and vibration environment, followed by one final deployment and stowing cycle on the ground, before its flight into space. The James Webb Space Telescope is scheduled to launch in 2021.

Video credit: NASA’s Goddard Space Flight Center, Greenbelt, Md./Aaron E. Lepsch (ADNET): Technical Support/Michael McClare (KBRwyle): Videographer/Sophia Roberts (AIMM): Videographer/Michael P. Menzel (AIMM): Video Editor

NASA dicit:

A new study of observations from NASA’s Fermi Gamma-ray Space Telescope has discovered a faint but sprawling glow around a nearby pulsar. If visible to the human eye, this gamma-ray halo would appear larger in the sky than the famed Big Dipper star pattern. The halo suggests this same pulsar could be responsible for a decade-long puzzle about one type of cosmic particle arriving from beyond the solar system that is unusually abundant near Earth — positrons, the antimatter version of electrons.

A neutron star is the crushed core left behind when a star much more massive than the Sun runs out of fuel, collapses under its own weight and explodes as a supernova. We see some neutron stars as pulsars, rapidly spinning objects emitting beams of radio waves, light, X-rays and gamma rays that, much like a lighthouse, regularly sweep across our line of sight from Earth.

Geminga (pronounced geh-MING-a) is among the brightest pulsars at gamma-ray energies. To study its halo, scientists had to subtract out all other sources of gamma rays, including diffuse light produced by cosmic ray collisions with interstellar gas clouds. Ten different models of interstellar emission were evaluated. What remained when these sources were removed was a vast, oblong glow spanning some 20 degrees — about 40 times the apparent size of a full Moon — at an energy of 10 billion electron volts (GeV), and even larger at lower energies.

The team determined that Geminga alone could be responsible for as much as 20% of the high-energy positrons seen by other space experiments. Extrapolating this to the cumulative emission of positrons from all pulsars in our galaxy, the scientists say it’s clear that pulsars remain the best explanation for the observed excess of positrons.

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Producer/Francis Reddy (University of Maryland College Park): Science writer/Mattia Di Mauro (Catholic University of America): Visualizer/Mattia Di Mauro (Catholic University of America): Scientist