Scientists have used all available New Horizons images of Arrokoth, taken from many angles, to determine its 3D shape, as shown in this animation. The shape provides additional insight into Arrokoth’s origins. The flattened shapes of each of Arrokoth’s lobes, as well as the remarkably close alignment of their poles and equators, point to an orderly, gentle merger of two objects formed from the same collapsing cloud of particles. Arrokoth has the physical features of a body that came together slowly, with ‘locally-sourced’ materials from a small part of the solar nebula. An object like Arrokoth wouldn’t have formed, or look the way it does, in a more chaotic accretion environment.
Video credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/James Tuttle Keane
The James Webb Space Telescope (JWST) is a space telescope that is planned to be the successor to the Hubble Space Telescope. The JWST will provide improved infrared resolution and sensitivity over Hubble, and will enable a broad range of investigations across the fields of astronomy and cosmology, including observing some of the most distant events and objects in the universe, such as the formation of the first galaxies. Other goals include understanding the formation of stars and planets, and direct imaging of exoplanets and novas.
The primary mirror of the JWST, the Optical Telescope Element, is composed of 18 hexagonal mirror segments made of gold-plated beryllium which combine to create a 6.5-meter (21 ft; 260 in) diameter mirror that is much larger than the Hubble’s 2.4-meter (7.9 ft; 94 in) mirror. Unlike the Hubble, which observes in the near ultraviolet, visible, and near infrared (0.1 to 1 μm) spectra, the JWST will observe in a lower frequency range, from long-wavelength visible light through mid-infrared (0.6 to 28.3 μm), which will allow it to observe high redshift objects that are too old and too distant for the Hubble to observe. The telescope must be kept very cold in order to observe in the infrared without interference, so it will be deployed in space near the Earth–Sun L2 Lagrangian point, and a large sunshield made of silicon- and aluminum-coated Kapton will keep its mirror and instruments below 50 K (−220 °C; −370 °F).
The JWST is being developed by NASA—with significant contributions from the European Space Agency and the Canadian Space Agency—and is named for James E. Webb, who was the administrator of NASA from 1961 to 1968 and played an integral role in the Apollo program.
The Solar Orbiter (SolO) is a planned Sun-observing satellite, under development by the European Space Agency (ESA). SolO is intended to perform detailed measurements of the inner heliosphere and nascent solar wind, and perform close observations of the polar regions of the Sun, which is difficult to do from Earth, both serving to answer the question “How does the Sun create and control the heliosphere?”
The science payload is composed of 10 instruments:
Heliospheric in-situ instruments
Solar Wind Analyser (SWA): To measure solar wind properties and composition; Energetic Particle Detector (EPD): To measure suprathermal ions, electrons, neutral atoms, as well as energetic particles in the energy range from few keV/nuc to relativistic electrons and ions up to 100 MeV (protons) and 200 MeV/nuc (heavy ions); Magnetometer (MAG): it will provide detailed measurements of the magnetic field; Radio and Plasma Wave analyser (RPW): To measure magnetic and electric fields at high time resolution.
Solar remote-sensing instruments
PHI: Polarimetric and Helioseismic Imager (Germany): To provide high-resolution and full-disc measurements of the photospheric vector magnetic field and line-of-sight (LOS) velocity as well as the continuum intensity in the visible wavelength range; EUI – Extreme Ultraviolet Imager (Belgium): To provide image sequences of the solar atmospheric layers above the photosphere, thereby providing an indispensable link between the solar surface and outer corona that ultimately shapes the characteristics of the interplanetary medium; SPICE – Spectral Imaging of the Coronal Environment (France): To perform extreme ultraviolet imaging spectroscopy to remotely characterize plasma properties of the Sun’s on-disc corona; STIX – Spectrometer Telescope for Imaging X-rays (Switzerland): To provides imaging spectroscopy of solar thermal and non-thermal X-ray emission from 4 to 150 keV; METIS – Coronagraph (Italy): To simultaneously image the visible, ultraviolet and extreme ultraviolet emission of the solar corona and diagnose, with unprecedented temporal coverage and spatial resolution, the structure and dynamics of the full corona in the range from 1.4 to 3.0 (from 1.7 to 4.1) solar radii from Sun centre, at minimum (maximum) perihelion during the nominal mission; SoloHI – Solar Orbiter Heliospheric Imager (United States): To image both the quasi-steady flow and transient disturbances in the solar wind over a wide field of view by observing visible sunlight scattered by solar wind electrons.
Video credit: NASA’s Goddard Space Flight Center/Genna Duberstein (ADNET): Lead Producer/Maria-Jose Vinas Garcia (Telophase): Translator/Aaron E. Lepsch (ADNET): Technical Support/Scott Wiessinger (USRA): Technical Support/Animation by ESA/ATG Medialab
The Solar Orbiter (SolO) is a planned Sun-observing satellite, under development by the European Space Agency (ESA). SolO is intended to perform detailed measurements of the inner heliosphere and nascent solar wind, and perform close observations of the polar regions of the Sun, which is difficult to do from Earth, both serving to answer the question “How does the Sun create and control the heliosphere?”
SolO will make observations of the Sun from an eccentric orbit moving as close as ~60 solar radii (RS), or 0.284 astronomical units (au), placing it inside Mercury’s perihelion of 0.3075 au. During the planned 7-year mission the orbital inclination will be raised to about 25°.
The spacecraft will make a close approach to the Sun every five months. The closest approach will be positioned to allow a repeated study of the same region of the solar atmosphere. Solar Orbiter will be able to observe the magnetic activity building up in the atmosphere that can lead to powerful solar flares or eruptions.
Researchers will also have the chance to coordinate observations with NASA’s Parker Solar Probe mission (2018-2025) which is performing measurements of the Sun’s extended corona.
The objective of the mission is to perform close-up, high-resolution studies of the Sun and its inner heliosphere. The new understanding will help answer these questions:
How and where do the solar wind plasma and magnetic field originate in the corona?
How do solar transients drive heliospheric variability?
How do solar eruptions produce energetic particle radiation that fills the heliosphere?
How does the solar dynamo work and drive connections between the Sun and the heliosphere?
A corona (meaning ‘crown’ in Latin derived from Ancient Greek ‘κοÏώνη’ (korÅnè, “garland, wreath”)) is an aura of plasma that surrounds the Sun and other stars. The Sun’s corona extends millions of kilometres into outer space and is most easily seen during a total solar eclipse, but it is also observable with a coronagraph.
Spectroscopy measurements indicate strong ionization in the corona and a plasma temperature in excess of 1000000 kelvin, much hotter than the surface of the Sun.
Light from the corona comes from three primary sources, from the same volume of space. The K-corona (K for kontinuierlich, “continuous” in German) is created by sunlight scattering off free electrons; Doppler broadening of the reflected photospheric absorption lines spreads them so greatly as to completely obscure them, giving the spectral appearance of a continuum with no absorption lines. The F-corona (F for Fraunhofer) is created by sunlight bouncing off dust particles, and is observable because its light contains the Fraunhofer absorption lines that are seen in raw sunlight; the F-corona extends to very high elongation angles from the Sun, where it is called the zodiacal light. The E-corona (E for emission) is due to spectral emission lines produced by ions that are present in the coronal plasma; it may be observed in broad or forbidden or hot spectral emission lines and is the main source of information about the corona’s composition.
Video credit: Video credit: NASA’s Goddard Space Flight Center/Genna Duberstein (USRA): Producer/Mara Johnson-Groh (Wyle Information Systems): Lead Writer/Tom Bridgman (GST): Data Visualizer/Chris Smith (USRA): Narrator/Aaron E. Lepsch (ADNET): Technical Support
A new spacecraft is journeying to the Sun to snap the first pictures of the Sun’s north and south poles. Solar Orbiter, a collaboration between ESA and NASA will have its first opportunity to launch from Cape Canaveral on February 7, 2020. Launching on a United Launch Alliance Atlas V rocket, the spacecraft will use Venus’ and Earth’s gravity to swing itself out of the ecliptic plane — the swath of space, roughly aligned with the Sun’s equator, where all planets orbit. From there, Solar Orbiter’s bird’s eye view will give it the first-ever look at the Sun’s poles.
Video credit: NASA’s Goddard Space Flight Center/Holly Gilbert (NASA/GSFC): Scientist/Teresa Nieves-Chinchilla (Catholic University of America): Scientist/Chris St. Cyr (NASA/GSFC): Scientist/Joy Ng (USRA): Producer/Tom Bridgman (GST): Data Visualizer/Adriana Manrique Gutierrez (USRA): Animator/Chris Smith (USRA): Animator/Joy Ng (USRA): Animator/Lisa Poje (USRA): Animator/Krystofer Kim (USRA): Animator/Brian Monroe (USRA): Animator/Miles S. Hatfield (Telophase): Writer
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