A sampling of recent articles, videos, and images from space-related science news items (find previous roundups here):
** What Does a Black Hole Look Like: How We Got Our First Picture – Dr. Eliot Quataert of the University of California, Berkeley gave this recent Silicon Valley Astronomy Lecture:
Black holes are one of the most remarkable predictions of Einstein’s theory of gravity: so much material is compressed into such a small volume that nothing, not even light, can escape. In Spring 2019, the world-wide Event Horizon Telescope released the first real picture of gas around a massive black hole and the “shadow” it makes as the gas swirls into the black hole. Dr. Quataert describes how these pioneering observations were made and what they have taught us about black
NASA’s Kepler spacecraft was designed to find exoplanets by looking for stars that dim as a planet crosses the star’s face. Fortuitously, the same design makes it ideal for spotting other astronomical transients – objects that brighten or dim over time. A new search of Kepler archival data has uncovered an unusual super-outburst from a previously unknown dwarf nova. The system brightened by a factor of 1,600 over less than a day before slowly fading away.
The star system in question consists of a white dwarf star with a brown dwarf companion about one-tenth as massive as the white dwarf. A white dwarf is the leftover core of an aging Sun-like star and contains about a Sun’s worth of material in a globe the size of Earth. A brown dwarf is an object with a mass between 10 and 80 Jupiters that is too small to undergo nuclear fusion.
The brown dwarf circles the white dwarf star every 83 minutes at a distance of only 250,000 miles (400,000 km) – about the distance from Earth to the Moon. They are so close that the white dwarf’s strong gravity strips material from the brown dwarf, sucking its essence away like a vampire. The stripped material forms a disk as it spirals toward the white dwarf (known as an accretion disk).
It was sheer chance that Kepler was looking in the right direction when this system underwent a super-outburst, brightening by more than 1,000 times. In fact, Kepler was the only instrument that could have witnessed it, since the system was too close to the Sun from Earth’s point of view at the time. Kepler’s rapid cadence of observations, taking data every 30 minutes, was crucial for catching every detail of the outburst.
The event remained hidden in Kepler’s archive until identified by a team led by Ryan Ridden-Harper of the Space Telescope Science Institute (STScI), Baltimore, Maryland, and the Australian National University, Canberra, Australia. “In a sense, we discovered this system accidentally. We weren’t specifically looking for a super-outburst. We were looking for any sort of transient,” said Ridden-Harper.
Kepler captured the entire event, observing a slow rise in brightness followed by a rapid intensification. While the sudden brightening is predicted by theories, the cause of the slow start remains a mystery. Standard theories of accretion disk physics don’t predict this phenomenon, which has subsequently been observed in two other dwarf nova super-outbursts.
NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.
TOI 700 d is one of only a few Earth-size planets discovered in a star’s habitable zone so far. Others include several planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler Space Telescope.
“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January.”
In 2019, when Wolf Cukier finished his junior year at Scarsdale High School in New York, he joined NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern. His job was to examine variations in star brightness captured by NASA’s Transiting Exoplanet Survey Satellite (TESS) and uploaded to the Planet Hunters TESS citizen science project.
“I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”
A SETI Institute view on the TESS findings:
** Voyager 2, 18.5 billion kilometers from earth, recovers after power glitch: Voyager 2 Engineers Working to Restore Normal Operations – NASA JPL
Engineers for NASA’s Voyager 2 spacecraft are working to return the mission to normal operating conditions after one of the spacecraft’s autonomous fault protection routines was triggered. Multiple fault protection routines were programmed into both Voyager 1 and Voyager 2 in order to allow the spacecraft to automatically take actions to protect themselves if potentially harmful circumstances arise. At NASA’s Jet Propulsion Laboratory in Pasadena, California, engineers are still communicating with the spacecraft and receiving telemetry.
Launched in 1977, Voyager 1 and Voyager 2 are both in interstellar space, making them the most distant human-made objects in the solar system. On Saturday, Jan. 25, Voyager 2 didn’t execute a scheduled maneuver in which the spacecraft rotates 360 degrees in order to calibrate its onboard magnetic field instrument. Analysis of the telemetry from the spacecraft indicated that an unexplained delay in the onboard execution of the maneuver commands inadvertently left two systems that consume relatively high levels of power operating at the same time. This caused the spacecraft to overdraw its available power supply.
It’s a long way to make a service call:
It has taken the team several days to assess the current situation primarily because of Voyager 2’s distance from Earth – about 11.5 billion miles (18.5 billion kilometers). Communications traveling at the speed of light take about 17 hours to reach the spacecraft, and it takes another 17 hours for a response from the spacecraft to return to Earth. As a result, mission engineers have to wait about 34 hours to find out if their commands have had the desired effect on the spacecraft.
** An update on activity on the Sun’s surface: Sunspot update: The record flatline continues | Behind The Black
In the month of December 2019 the Sun continued its longest stretch of overall sunspot inactivity ever recorded, reaching seven months in length. At no point since the last grand minimum in the 1600s have scientists ever seen so few sunspots over so long a time period.
December saw only two sunspots, both becoming active on the same day, December 24. Both also had a polarity belonging to the next solar cycle, providing evidence that we will have another sunspot maximum sometime in the next five years, and that we are not heading to another grand minimum where there are no sunspots for decades.
See SpaceWeather.com for daily updates on sunspots.
** Parker Solar Probe sets new record for spacecraft nearness to the Sun: Parker Solar Probe Completes Fourth Closest Approach, Breaks New Speed and Distance Records – Parker Solar Probe/NASA
At 4:37 a.m. EST on Jan. 29, 2020, NASA’s Parker Solar Probe broke speed and distance records as it completed its fourth close approach of the Sun. The spacecraft traveled 11.6 million miles from the Sun’s surface at perihelion, reaching a speed of 244,225 miles per hour. These achievements topple Parker Solar Probe’s own previous records for closest spacecraft to the Sun — previously about 15 million miles from the Sun’s surface — and fastest human-made object, before roughly 213,200 miles per hour.
Parker Solar Probe will continue to fly ever closer to the Sun on its seven-year journey, exploring regions of space never visited before and providing scientists with key measurements to help unveil the mysteries of the solar corona and wind.
As with most of Parker Solar Probe’s close approaches, the spacecraft is out of contact with Earth for several days around perihelion.
Listen to the sounds of the Sun as recorded by the probe: Parker Solar Probe Team Hears First Whispers of the Solar Wind’s Birth – JHU-APL
There’s a wind that emanates from the Sun. It blows not like a soft whistle but like a hurricane’s scream. Made of electrons, protons and heavier ions, the solar wind courses through the solar system at roughly 1 million mph (1.6 million kph), barreling over everything in its path. Yet through the wind’s roar, NASA’s Parker Solar Probe hears the small chirps, squeaks and rustles that hint at the origin of this mysterious and ever-present wind. The spacecraft’s FIELDS instrument can eavesdrop on the electric and magnetic fluctuations caused by plasma waves. The Parker Solar Probe it can “hear” when the waves and particles interact with one another, recording frequency and amplitude information about these plasma waves that scientists could then play as sound waves. And it results in some striking sounds. Solar wind sounds playlist: https://soundcloud.com/jhu-apl/sets/s…
It’s more massive than all the other planets combined. In nearly four years at Jupiter the Juno spacecraft has returned science that is revolutionizing our understanding of this gigantic world. Principal investigator Scott Bolton shows us the mysterious cyclones at its poles and that famously persistent red spot. Casey Dreier says the United States House of Representatives has proposed legislation that is at odds with NASA’s current Moon and Mars plans. John Flamsteed almost discovered Uranus! Bruce Betts will tell us where he went wrong in this week’s What’s Up space trivia contest.
** China releases data and imagery from Chang’e 4 mission to the Moon’s far side:
- Chang’e 4 scientific data is released – Moon.bao.ac.cn
- Data publishing and information service system of lunar exploration program – Moon.bao.ac.cn
- China publishes Chang’e 4 data one year after first landing on far side of the moon – Spaceflight Now
Chinese officials marked the one-year anniversary of the Chang’e 4 mission’s historic first soft landing on the far side of the moon [January 3rd] with the public release of data collected by scientific instruments and cameras on the lunar lander and rover.
The Chang’e 4 lander and Yutu 2 rover landed together on the lunar surface Jan. 3, 2019, marking the first time a spacecraft has ever safely touched down on the far side of the moon.
Around 12 hours after touchdown, the Yutu 2 rover drove down a ramp to disembark from the Chang’e 4 mission’s stationary landing platform to begin exploring the barren lunar landscape.
Scientific instruments and cameras aboard the Chang’e 4 lander and Yutu 2 rover have downlinked measurements and numerous images in the past year. The Chang’e 4 mission relays data through a dedicated Chinese communications satellite positioned beyond the far side of the moon, with a line of sight to both Chang’e 4 and Earth-based receiving stations.
On Friday, the one-year anniversary of the mission’s successful landing, China National Space Administration and the Chinese Academy of Sciences published scientific data collected by five instruments on the Chang’e 4 lander and Yutu 2 rover.
** In December the OSIRIS-REx team selected a spot for sample-taking on asteroid Bennu. Next August, the spacecraft will land briefly and grab a sample of regolith to return to Earth in 2023: X Marks the Spot: NASA Selects Site for Asteroid Sample Collection – OSIRIS-REx Mission
After a year scoping out asteroid Bennu’s boulder-scattered surface, the team leading NASA’s first asteroid sample return mission has officially selected a sample collection site.
The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-Rex) mission team concluded a site designated “Nightingale” – located in a crater high in Bennu’s northern hemisphere – is the best spot for the OSIRIS-REx spacecraft to snag its sample.
The OSIRIS-REx team spent the past several months evaluating close-range data from four candidate sites in order to identify the best option for the sample collection. The candidate sites – dubbed Sandpiper, Osprey, Kingfisher, and Nightingale – were chosen for investigation because, of all the potential sampling regions on Bennu, these areas pose the fewest hazards to the spacecraft’s safety while still providing the opportunity for great samples to be gathered.
This month the spacecraft made a low pass over the Nightingale spot to inspect it further: OSIRIS-REx Completes Closest Flyover of Sample Site Nightingale – OSIRIS-REx Mission
Preliminary results indicate that NASA’s OSIRIS-REx spacecraft successfully executed a 0.4-mile (620-m) flyover of site Nightingale yesterday as part of the mission’s Reconnaissance B phase activities. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater high in asteroid Bennu’s northern hemisphere.
To perform the pass, the spacecraft left its 0.75-mile (1.2-km) safe home orbit and flew an almost 11-hour transit over the asteroid, aiming its science instruments toward the 52-ft (16-m) wide sample site before returning to orbit. Science observations from this flyover are the closest taken of a sample site to date.
The primary goal of the Nightingale flyover was to collect the high-resolution imagery required to complete the spacecraft’s Natural Feature Tracking image catalog, which will document the sample collection site’s surface features – such as boulders and craters. During the sampling event, which is scheduled for late August, the spacecraft will use this catalog to navigate with respect to Bennu’s surface features, allowing it to autonomously predict where on the sample site it will make contact . Several of the spacecraft’s other instruments also took observations of the Nightingale site during the flyover event, including the OSIRIS-REx Thermal Emissions Spectrometer (OTES), the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), the OSIRIS-REx Laser Altimeter (OLA), and the MapCam color imager.
** The European Mars Express views the northern ice cap: Rippling ice and storms at Mars’ north pole – ESA
** Updates on Curiosity‘s roving from Leonard David:
- Curiosity Mars Rover: Mudstones, Sandstones, Drive Ahead
- Curiosity Mars Rover: Rock On Rock, Sand Ripples, New Scenic Shots (Updated)
- Curiosity Mars Rover: Excellent View, Drive Ahead
- Curiosity Mars Rover: New Images, New Road Map
- Curiosity Mars Rover: Ready for More Science
** More of the marvelous Martian surface – Bob Zimmerman
- Inexplicable ridges on Mars
- More evidence of ample shallow ice in Martian mid-latitudes
- The beginning of chaos on Mars
- Martian pimples
- Undulations on Mars
- Six Martian summers at a polar impact crater
- Gully on Mars
- Pedestal craters in the Martian northern lowlands?
** Insight‘s mole digs in reverse again:
After making good progress in recent weeks, another day of digging on #Mars leads to the mole backing out by a couple of centimeters. My team keeps pushing forward and is exploring several options. pic.twitter.com/pe2eopDANi
— NASA InSight (@NASAInSight) January 21, 2020
- China Pegs July for Mars Launch – Leonard David
- It’s official: China’s first Mars lander debuts – CGTN
- Mars Global Remote Sensing Orbiter and Small Rover – Wikipedia
NASA’s Mars 2020 mission aims to launch during a window between July 17 – Aug. 5, 2020 and land on Feb. 18, 2021. The rover is of a similar design to that of Curiosity, which landed on Mars on August 5, 2012. The Mars 2020 rover will soon get a name as well: Nine Finalists Chosen in NASA’s Mars 2020 Rover Naming Contest – NASA’s Mars Exploration Program.
The joint European/Russian ExoMars 2020 mission aims to launch on a Russian Proton rocket this summer and land on Mars on March 19, 2021. Problems with the parachutes need to be resolved else the mission will have to wait another two years for the next launch window: Promising progress for ExoMars parachutes – ESA
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