The Artemis program is an ongoing crewed spaceflight program carried out predominately by NASA, U.S. commercial spaceflight companies, and international partners such as the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), and the Canadian Space Agency (CSA) with the goal of landing “the first woman and the next man” on the Moon, specifically at the lunar south pole region by 2024. NASA sees Artemis as the next step towards the long-term goal of establishing a sustainable presence on the Moon, laying the foundation for private companies to build a lunar economy, and eventually sending humans to Mars.
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
Thuban, designation Alpha Draconis (α Draconis, abbreviated Alpha Dra, α Dra), is a star (or star system) in the constellation of Draco. A relatively inconspicuous star in the night sky of the Northern Hemisphere, it is historically significant as having been the north pole star from the 4th to 2nd millennium BCE. Even though Johann Bayer gave Thuban the designation Alpha, its apparent magnitude of 3.65 means it is 3.7 times fainter than the brightest star in the constellation, Gamma Draconis (Eltanin), whose apparent magnitude is 2.24.
Due to the precession of Earth’s rotational axis, Thuban was the naked-eye star closest to the north pole from 3942 BCE, when it superseded Iota Draconis as the Pole Star, until 1793 BCE, when it was superseded by Kappa Draconis. It was closest to the pole in 2830 BCE, when it was less than ten arc-minutes away from the pole. It remained within one degree of celestial north for nearly 200 years afterwards, and even 900 years after its closest approach, was just five degrees off the pole. Thuban was considered the pole star until about 1800 BCE, when the much brighter Beta Ursae Minoris (Kochab) began to approach the pole as well.
Having gradually drifted away from the pole over the last 4,800 years, Thuban is now seen in the night sky at a declination of 64° 20′ 45.6″, RA 14h 04m 33.58s. After moving nearly 47 degrees off the pole by 10000 CE, Thuban will gradually move back toward the north celestial pole. In 20346 CE, it will again be the pole star, that year reaching a maximum declination of 88° 43′ 17.3″, at right ascension 19h 08m 54.17s.
Video credit: NASA/ Chris Smith (USRA): Lead Producer/Chris Smith (USRA): Lead Animator/Francis Reddy (University of Maryland College Park): Lead Science Writer
NASA’s Wide Field Infrared Survey Telescope, WFIRST, will capture the equivalent of 100 high-resolution Hubble images in a single shot, imaging large areas of the sky 1,000 times faster than Hubble. In several months, WFIRST could survey as much of the sky in near-infrared light—in just as much detail—as Hubble has over its entire three decades.
Although WFIRST has not yet opened its wide, keen eyes on the universe, astronomers are already running simulations to demonstrate what it will be able to see and plan their observations. The simulated image of a portion of our neighboring galaxy Andromeda (M31) provides a preview of the vast expanse and fine detail that can be covered with just a single pointing of WFIRST. Using information gleaned from hundreds of Hubble observations, the simulated image covers a swath roughly 34,000 light-years across, showcasing the red and infrared light of more than 50 million individual stars detectable with WFIRST.
While it may appear to be a somewhat haphazard arrangement of 18 separate images, the simulation actually represents a single shot. Eighteen square detectors, 16-megapixels each, make up WFIRST’s Wide Field Instrument (WFI) and give the telescope its unique window into space. With each pointing, WFIRST will cover an area roughly 1â…“ times that of the full Moon. By comparison, each individual infrared Hubble image covers an area less than 1% of the full Moon.
WFIRST is designed to collect the big data needed to tackle essential questions across a wide range of topics, including dark energy, exoplanets, and general astrophysics spanning from our solar system to the most distant galaxies in the observable universe. Over its 5-year planned lifetime, WFIRST is expected to amass more than 20 petabytes of information on thousands of planets, billions of stars, millions of galaxies, and the fundamental forces that govern the cosmos.
Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Lead Producer/Ben Williams (U. Washington, Seattle): Visualizer/Scott Wiessinger (USRA): Narrator
In February 2020, NASA’s Solar Dynamics Observatory — SDO — is celebrating its 10th year in space. Over the past decade the spacecraft has kept a constant eye on the Sun, studying how the Sun creates solar activity and drives space weather — the dynamic conditions in space that impact the entire solar system, including Earth.
Since its launch on February 11, 2010, SDO has collected millions of scientific images of our nearest star, giving scientists new insights into its workings. SDO’s measurements of the Sun — from the interior to the atmosphere, magnetic field, and energy output — have greatly contributed to our understanding of our closest star. SDO’s images have also become iconic — if you’ve ever seen a close-up of activity on the Sun, it was likely from an SDO image.
Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Lead Producer/Mara Johnson-Groh (Wyle Information Systems): Science Writer/Barb Mattson (University of Maryland College Park): Narrator
NASA’s Solar Dynamics Observatory (SDO) stares at our sun in high-definition from space. Under the spacecraft’s constant gaze the sun’s invisible magnetic field betrays its presence by bending charged gas, or plasma, into entrancing patterns. In February 2012, SDO captured curious images in which plasma near the sun’s surface appears to swirl like debris in a tornado. But was the plasma really rotating? Some scientists believe the spinning is an illusion caused by a 2-D projection of 3-D motion, while others think it is truly twisting. Newer observations may show more clearly that some of the material is moving toward Earth while some is moving away, pointing to genuine rotation. If that’s the case, bunched magnetic fields at the sun’s surface could be causing the elaborate plasma dance by becoming tangled themselves.
Video credit: NASA’s Goddard Space Flight Center/Visualizer/Animator: Tom Bridgman (GST)/Producers: Michael Starobin (HTSI),Scott Wiessinger (USRA)/Scientists: Yang Su (University of Graz), Todd Hoeksema (Stanford)/Writer: Chris Cesare (USRA)
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