Universe Today

September 5, 2024September 9, 2024 by Matt Williams

Ouch! A Monster Asteroid Crashed Into Ganymede 4 Billion Years Ago, Rolling it Over

Artist's impression of the large impact that caused Ganymede to reorient itself 4 billion years ago. © HIRATA Naoyuki

Jupiter’s moon, Ganymede, is a fascinating celestial body. Measuring 5,268 km (3,272 mi) in diameter, it is also the largest satellite in the Solar System and even larger than Mercury, which measures 4,880 km (3,032 mi) in diameter. Like Europa, it has an interior ocean and is one of the few bodies in the Solar System (other than the gas giants) with an intrinsic magnetic field. The presence of this field also means Ganymede experiences aurorae circling the regions around its northern and southern poles due to interaction with Jupiter’s magnetic field.

In addition, based on its surface craters, scientists believe that Ganymede experienced a powerful impact with an asteroid about 4 billion years ago. This asteroid was about 20 times larger than the Chicxulub asteroid that caused the extinction of the dinosaurs, or the Cretaceous–Paleogene extinction event (ca. 66 million years ago). According to a recent study by Naoyuki Hirata of Kobe University, this impact occurred almost precisely on the meridian farthest away from Jupiter. This caused a reorientation of Ganymede’s rotational axis and allowed Hirata to determine exactly what type of impact took place.

September 5, 2024September 5, 2024 by Mark Thompson

NASA’s Putting its Solar Sail Through its Paces

Those of you following the Advanced Composite Solar Sail System may have heard that its booms and sail are now deployed. It is receiving light pressure from the Sun to propel it through the Solar System. Like a test pilot in a new aircraft, NASA are now testing out just how it handles. Before deployment, the spacecraft was slowly tumbling and now the controllers will see if they can get it under control and under sail power. The reflectivity of the sail means its an easy spot in the night sky, just fire up the NASA app to find out where to look.

September 5, 2024September 5, 2024 by Matt Williams

There are Important Differences Between the Ice Caps on Mars

This image shows eroded channels near the Martian poles filled with bright frozen carbon dioxide, in contrast to the muted red of the underlying ground. Credit:NASA/JPL/University of Arizona

In the 17th century, astronomers Giovanni Domenica Cassini and Christian Huygens noted the presence of hazy white caps while studying the Martian polar regions. These findings confirmed that Mars had ice caps in both polar regions, similar to Earth. By the 18th century, astronomers began to notice how the size of these poles varied depending on where Mars was in its orbital cycle. Along with discovering that Mars’ axis was tilted like Earth’s, astronomers realized that Mars’ polar ice caps underwent seasonal changes, much like Earth’s.

While scientists have been aware that Mars’ polar ice caps change with the seasons, it has only been within the last 50 years that they have realized that they are largely composed of frozen carbon dioxide (aka. “dry ice”) that cycles in and out of the atmosphere – and questions as to how this happens remain. In a recent study, a team of researchers led by the Planetary Science Institute (PSI) synthesized decades of research with more recent observations of the poles. From this, they determined how the Martian poles differ in terms of their seasonal accumulation and release of atmospheric carbon dioxide.

September 5, 2024September 5, 2024 by Evan Gough

Archaeological Methods Reveal How Astronauts Work on the International Space Station

Archaeology is the study of human prehistory, so it seems incongruous to use its methods to study how humans behave in space. But that’s what astronauts aboard the International Space Station are doing.

September 5, 2024September 5, 2024 by Mark Thompson

Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles

The Universe often puts on a good show for us down here on Earth but one of the best spectacles must be a meteor shower. We see them when particles, usually the remains of comets, fall through our atmosphere and cause the atmosphere to glow. We see them as a fast moving streak of light but a new paper has suggested that the meteor showers we see can explain the sizes of the particles that originally formed the comet from where they came.

September 4, 2024September 4, 2024 by Evan Gough

Dark Oxygen Could Change Our Understanding of Habitability

This image shows a bed of manganese nodules offshore of the Cook Islands. Dark oxygen is produced by manganese nodules on the ocean floor. If the same thing happens on the Solar System's ocean moons, it changes our notion of what worlds could be habitable. Image Credit: By USGS, James Hein - https://www.usgs.gov/media/images/cook-islands-manganese-nodules, CC0, https://commons.wikimedia.org/w/index.php?curid=115692552

The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?

What does it mean for our notion of habitability?

September 4, 2024September 4, 2024 by Evan Gough

A Surprise Asteroid Lit Up the Sky Over the Philippines

This image shows the predicted path over the Philippines for the surprise asteroid 2024 RW1. It's small and will burn up harmlessly. Image Credit: Catalina Sky Survey/ESA

With all of humanity’s telescopic eyes on the sky, it’s rare for an asteroid to take us by surprise. But that’s what happened this morning in the sky over the Philippines. Only hours after it was detected, it burned up in a bright flash above the island of Luzon.

September 4, 2024September 4, 2024 by Matt Williams

A Review of Humanity’s Planned Expansion Between the Earth and the Moon

Artist's impression of astronauts on the lunar surface, as part of the Artemis Program. Credit: NASA

Between Low Earth Orbit (LEO) and the Moon, there is a region of space measuring 384,400 km (238,855 mi) wide known as Cislunar space. In the coming decades, multiple space agencies will send missions to this region to support the development of infrastructure that will lead to a permanent human presence on the Moon. This includes orbital and surface habitats, landing pads, surface vehicles, technologies for in-situ resource utilization (ISRU), and other elements that will enable the long-term exploration and development of the lunar surface.

For all parties concerned, Cislunar space holds immense potential in terms of scientific, commercial, and military applications. The vastly increased level of activity on and around the Moon makes space domain awareness (SDA) – knowledge of all operations within a region of space – paramount. It is also necessary to ensure the continued success and utilization of the covered region. In a recent paper, a team of aerospace engineers considered the missions planned for the coming decades and evaluated the state and shortcomings of their space domain awareness.

September 4, 2024September 4, 2024 by Mark Thompson

Simulating the Accretion Disk Around a Black Hole

Supercomputer simulations reveals the nature of turbulence in black hole accretion disks

Black holes are by their very nature, challenging to observe and difficult to spot. It’s usually observations of the accretion disk that reveal properties of the hidden black hole. There is often enough material within the accretion disk to make them shine so brightly that they can often be among the brightest objects in space. A wonderful image has been released which shows the highest resolution simulation of a black hole accretion disk ever created.

September 4, 2024September 4, 2024 by Mark Thompson

Europe is Sending a Drill to the Moon to Search for Water

ESA's Prospect package, including drill and a miniaturised laboratory, will fly to the Moon’s South Polar region in search of volatiles, including water ice, as part of NASA’s Commercial Lunar Payload Services initiative.

The Moon has been a source of interest of late largely due to the focus on getting humans back to the Moon. Future human explorers though will likely be there to stay in permanent lunar bases. Making this a reality means it is of vital importance to harvest materials from the Moon and water is just one of them. Recently, ESA Announced they have secured a ride to the Moon for their Prospect package in 2027. It consists of a drill and tiny laboratory that will hunt for water and other volatiles, paving the way for human exploration.