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November 17, 2022November 17, 2022 by David Dickinson

Are We in for a Leonid Outburst Friday Night?

Leonid from 2001 — A lone Leonid meteor from 2001. Image credit and copyright: Frankie Lucena.

The November Leonid meteors may produce a surprise outburst this weekend.

If forecasters are right, a notorious meteor shower may put on a surprise showing soon, right after its expected peak. The meteor shower in question is the November Leonids. Most years, the Leonids are really nothing to wake up early for, producing an average hourly rate of 10 meteors an hour, barely double the background sporadic rate. But every 33 years or so, the Leonids are the source of great storms of meteors, as the Earth plows headlong into the stream of debris laid down by comet 55P/Tempel-Tuttle on its 33-year orbit around the Sun.

November 16, 2022November 16, 2022 by Matt Williams

Greenland’s ice Loss is Worse Than We Thought

Cumulative melt days on the Greenland Ice Sheet for the 2022 melt season (left) and difference from the 1981 to 2010 average melt days for the same period (right). Credit: NSIDC/T. Mote, University of Georgia

Climate change is the single greatest threat facing our planet today. Thanks to excess carbon emissions that have been growing steadily since the mid-20th century, average temperatures continue to rise worldwide. This leads to feedback mechanisms, such as rising sea levels, extreme weather, drought, wildfires, and glacial melting. This includes the Arctic Ice Pack, the East Antarctic glacier, and the Greenland Ice Sheet (GrIS), which are rapidly melting and increasing global sea levels.

Worse than that, the disappearance of the world’s ice sheets means that Earth’s surface and oceans absorb more heat, driving global temperatures even further. According to a new NASA-supported study by an international team of Earth scientists and glaciologists, the Greenland Ice Sheet is melting at an accelerating rate, much faster than existing models predict. According to these findings, far more ice will be lost from Greenland during the 21st century, which means its contribution to sea-level rise will be significantly higher.

November 16, 2022November 16, 2022 by Matt Williams

What Would Asteroid Mining do to the World's Economy?

Artist's impression of an astronaut conducting an EVA with an asteroid. Credit: NASA

About a decade ago, the prospect of “asteroid mining” saw a massive surge in interest. This was due largely to the rise of the commercial space sector and the belief that harvesting resources from space would soon become a reality. What had been the stuff of science fiction and futurist predictions was now being talked about seriously in the business sector, with many claiming that the future of resource exploitation and manufacturing lay in space. Since then, there’s been a bit of a cooling off as these hopes failed to materialize in the expected timeframe.

Nevertheless, there is little doubt that a human presence in space will entail harvesting resources from Near Earth Asteroids (NEAs) and beyond. In a recent paper, a team of researchers from the University of Nottingham in Ningbo, China, examined the potential impact of asteroid mining on the global economy. Based on their detailed assessment that includes market forces, environmental impact, asteroid and mineral type, and the scale of mining, they show how asteroid mining can be done in a way that is consistent with the Outer Space Treaty (i.e., for the benefit of all humanity).

November 14, 2022November 14, 2022 by Matt Williams

It’ll be Tough to Stop an Asteroid at the Last Minute, but not Impossible

Artist's impression of the DART mission impacting the moonlet Dimorphos. Credit: ESA

On September 26th, 2022, NASA’s Double-Asteroid Redirect Test (DART) made history when it rendezvoused with the asteroid Didymos and impacted with its moonlet, Dimorphos. The purpose was to test the “Kinetic Impact” method, a means of defense against potentially-hazardous asteroids (PHAs) where a spacecraft collides with them to alter their trajectory. Based on follow-up observations, the test succeeded since DART managed to shorten Dimorphos’ orbit by 22 minutes. The impact also caused the moonlet to grow a visible tail!

However, as Hollywood loves to remind us, there are scenarios where a planet-killing asteroid gets very close to Earth before we could do anything to stop it. And there is no shortage of Near Earth Asteroids (NEAs) that could become potential threats someday. Hence why space agencies worldwide make it a habit of monitoring them and how close they pass to Earth. According to a new study by a group of satellite experts, it would be possible to build a rapid-response kinetic impactor mission that could rendezvous and deflect a PHA shortly before it collided with Earth.

November 9, 2022November 9, 2022 by Matt Williams

The Case of the “Missing Exoplanets”

An illustration of the variations among the more than 5,000 known exoplanets discovered since the 1990s. Could their stars' metallicity play a role in making them habitable to life? Credit: NASA/JPL-Caltech

Today, the number of confirmed exoplanets stands at 5,197 in 3,888 planetary systems, with another 8,992 candidates awaiting confirmation. The majority have been particularly massive planets, ranging from Jupiter and Neptune-sized gas giants, which have radii about 2.5 times that of Earth. Another statistically significant population has been rocky planets that measure about 1.4 Earth radii (aka. “Super-Earths”). This presents a mystery to astronomers, especially where the exoplanets discovered by the venerable Kepler Space Telescope are concerned.

Of the more than 2,600 planets Kepler discovered, there’s an apparent rarity of exoplanets with a radius of about 1.8 times that of Earth – which they refer to as the “radius valley.” A second mystery, known as “peas in a pod,” refers to neighboring planets of similar size found in hundreds of planetary systems with harmonious orbits. In a study led by the Cycles of Life-Essential Volatile Elements in Rocky Planets (CLEVER) project at Rice University, an international team of astrophysicists provide a new model that accounts for the interplay of forces acting on newborn planets that could explain these two mysteries.

November 8, 2022November 8, 2022 by Matt Williams

China Launches Mengtian, the Last Major Module to its Space Station

Artist's rendering of the completed Tiangong space station. Credit: Shujianyang/Wikimedia

On the afternoon of Monday, October 31st, 2022 (Halloween!), China launched the Mengtian laboratory cabin module into space, where it will join the Tiangong modular space station. This module, whose name translates to “Dreaming of the Heavens,” is the second laboratory and final addition to Tiangong (“Palace in the Sky”). This successful launch places China one step closer to completing its first long-term space station, roughly one-fifth the mass of the International Space Station (ISS) and comparable in size to Russia’s decommissioned Mir space station.

November 7, 2022February 7, 2023 by Matt Williams

Hubble saw Multiple Light Echoes Reflecting off Rings of Dust From a Supernova Explosion

Artist view of a supernova explosion. Credit: NASA

When stars reach the end of their life cycle, they experience gravitational collapse at their centers and explode in a fiery burst (a supernova). This causes them to shed their outer layers and sends an intense burst of light and high-energy short-wavelength radiation (like X-rays and gamma-rays) out in all directions. This process also creates cosmic rays, which consist of protons and atomic nuclei that are accelerated to close to the speed of light. And on rare occasions, supernovae can also create “light echoes,” rings of light that spread out from the site of the original explosion.

These echoes will appear months to years after the supernova occurs as light from the explosion interacts with the layers of dust in the vicinity. Using the Hubble Space Telescope (HST), an international team of astronomers was able to document the emergence and evolution of multiple light echoes (LEs). The team traced these echoes to a stripped-envelope supernova (SN 2016adj) located in the central dust lane of Centaurus A, a galaxy located 10 to 16 million light-years away in the constellation of Centaurus.

November 6, 2022November 6, 2022 by Matt Williams

Mars is Mostly Dead. There's Still Magma Inside, so it's Slightly Alive

Artist's concept of InSight "taking the pulse of Mars". Credit: NASA/JPL-Caltech

Since February 2019, NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander has been making the first-ever measurements of tectonics on another planet. The key to this is InSight’s Seismic Experiment for Interior Structure (SEIS) instrument (developed by seismologists and geophysicists at ETH Zurich), which has been on the surface listening for signs of “marsquakes.” The dataset it has gathered (over 1,300 seismic events) has largely confirmed what planetary scientists have long suspected: that Mars is largely quiet.

However, a research team led by ETH Zurich recently analyzed a cluster of more than 20 recent marsquakes, which revealed something very interesting. Based on the location and spectral character of these events, they determined that most of Mars’ widely distributed surface faults are not seismically active. Nevertheless, most of the 20 seismic events observed originated in the vicinity of Cerberus Fossae, a region consisting of rifts (or graben). These results suggest that geological activity and volcanism still play an active role in shaping the Martian surface.

November 4, 2022November 4, 2022 by David Dickinson

Our Guide to Tuesday’s Total Lunar Eclipse

The November 8th total lunar eclipse spans the Pacific and is the last until 2025.

Set your alarms: if skies cooperate, next Tuesday morning’s lunar eclipse on November 8^th is worth getting up for and braving the cold. Not only is this one of the top astronomical events for 2022, but it’s also the last total lunar eclipse for a while…until, in fact, March 14, 2025.

November 3, 2022November 3, 2022 by Matt Williams

The Moon had Volcanoes More Recently Than Previously Believed

New measurements of lunar rocks have demonstrated that the ancient moon generated a dynamo magnetic field in its liquid metallic core (innermost red shell). The results raise the possibility of two different mechanisms — one that may have driven an earlier, much stronger dynamo, and a second that kept the moon’s core simmering at a much slower boil toward the end of its lifetime. Credit: Hernán Cañellas/Benjamin Weiss

Fifty years ago, NASA and the Soviet space program conducted the first sample-return missions from the Moon. This included lunar rocks brought back to Earth by the Apollo astronauts and those obtained by robotic missions that were part of the Soviet Luna Program. The analysis of these rocks revealed a great deal about the Moon’s composition, formation, and geological history. In particular, scientists concluded that the rocks were formed from volcanic eruptions more than three billion years ago.

In recent years, there has been a resurgence in lunar exploration as NASA and other space agencies have sent robotic missions to the Moon (in preparation for crewed missions). For instance, China has sent multiple orbiters, landers, and rovers to the Moon as part of the Chang’e program, including sample-return missions. A new study led by planetary scientists from the Chinese Academy of Sciences (CAS) analyzed samples obtained by the Chang’e-5 rover dated to two billion years ago. Their research could provide valuable insight into how young volcanism shaped the lunar surface.