Astro Blog

https://www.sciencemag.org/news/2019/04/first-marsquake-detected-nasas-insight-mission Source:   By Paul Voosen, Science Magazine. Excerpt: After several months of apprehensive waiting on a quiet surface, NASA’s InSight lander has registered a sweet, small sound: the first marsquake ever recorded. On 6 April, the lander’s seismometer detected its first verifiable quake, NASA and its European partners announced today. The quake is tiny, so small that it would never be detected on Earth amid the background thrum of waves and wind. But Mars is dead quiet, allowing the lander’s sensitive seismometer to pick up the signal, which resembles similar surface ripples detected traveling through the moon’s surface after moonquakes. The quake is so small that scientists were unable to detect any waves tied to it that passed through the martian interior, defying efforts to estimate its exact location and strength, says Philippe Lognonné, a planetary seismologist at Paris Diderot University who l

https://eos.org/research-spotlights/how-the-moon-got-its-concentric-rings Source:   By Emily Underwood, Eos/AGU. Excerpt: The Moon is pockmarked with impact craters from collisions with meteorites and asteroids, some as big as 1,000 kilometers in diameter. These massive impact craters contain three or more concentric rings, a mysterious feature that has long intrigued scientists interested in how Earth’s early surface and those of other planets evolved. Now a new study, in which scientists simulated an asteroid bigger than New York City slamming into a Moon-like object, explores how such rings form. ...To get a fresh perspective on this complex crater structure, Johnson et al. took advantage of data from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission: two washing machine–sized spacecraft that orbit the Moon and produce a high-resolution map of its gravitational field. Using this new, 10-kilometer-scale data, the authors were able to build a high-resolution computer

https://www.sciencenews.org/article/black-hole-first-picture-event-horizon-telescope Source:   By Lisa Grossman and Emily Conover, ScienceNews. Excerpt: A world-spanning network of telescopes called the Event Horizon Telescope [EHT; https://eventhorizontelescope.org/ ] zoomed in on the supermassive monster in the galaxy M87 to create this first-ever picture of a black hole.  ...“We’ve been studying black holes so long, sometimes it’s easy to forget that none of us have actually seen one,” France Córdova, director of the National Science Foundation....  ...The image also provides a new measurement of the black hole’s size and heft. ...Estimates made using different techniques have ranged between 3.5 billion and 7.22 billion times the mass of the sun. But the new EHT measurements show that its mass is about 6.5 billion solar masses. ...The team has also determined the behemoth’s size — its diameter stretches 38 billion kilometers — and that the black hole spins clockwise. “M87 is a m

https://www.sciencemag.org/news/2019/04/japanese-spacecraft-may-have-just-blown-crater-distant-asteroid Source:   By Dennis Normile, Science Magazine. Excerpt: Japan’s Hayabusa2 mission continued its unprecedented explorations today by apparently creating an artificial crater in an asteroid, a space exploration first. Officials confirmed that the operation to fire a projectile into asteroid Ryugu went smoothly, though as of early evening Japan time they were still trying to confirm whether a crater had actually been formed. ...Developed by the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science in Sagamihara, Hayabusa2 was launched in December 2014 and traveled 3.2 billion kilometers through space before reaching its home position 20 kilometers away from Ryugu, a diamond-shaped asteroid about 1 kilometer by 900 meters in size orbiting between Earth and Mars. The mission’s objective is to collect samples both from Ryugu’s surface and its interior and re

https://www.sciencemag.org/news/2019/04/astronomers-spy-iron-planet-stripped-its-crust-around-burned-out-star Source:   By Daniel Clery, Science Magazine. Excerpt: In a glimpse of what may be in store for our own solar system, astronomers have discovered what appear to be the shattered remains of a planet orbiting a white dwarf, the burned-out ember of a star like our sun. If the team’s calculations are correct, the orbiting object may be the iron core of a small planet that had its outer layers ripped off by the white dwarf’s intense gravity. Although astronomers know of thousands of exoplanets in the Milky Way, they struggle to see anything much smaller than Earth. The new object is by far the smallest, more of an asteroid than a planet. ...Finding the planetesimal, 400 light-years from Earth, wasn’t easy.  ...Most exoplanets can’t be seen directly, but are found when they cast a shadow crossing the face of their star or when they tug their star back and forth with the force of t