Mark Thompson, Author at Universe Today

November 20, 2024November 20, 2024 by Mark Thompson

How Could Astronauts Call for Help from the Moon?

Exploring the Moon poses significant risks, with its extreme environment and hazardous terrain presenting numerous challenges. In the event of a major accident, assistance might take days or even weeks to arrive. To address this, Australian researchers have created a distress alert system based upon the COSPAS-SARSAT technology used for Earth-based search and rescue operations. It relies on low-power emergency beacons that astronauts could activate with minimal setup and use a planned lunar satellite network for communication and rescue coordination.

November 20, 2024November 20, 2024 by Mark Thompson

There Was a 15 Minute Warning Before Tonga Volcano Exploded

Infrared satellite image (10.4 ?m) taken by Himawari-8 for the last reported event on January 14

Volcanoes are not restricted to the land, there are many undersea versions. One such undersea volcano known as Hunga Tonga-Hunga Ha’apai off the coast of Tonga. On 15th January 2022, it underwent an eruption which was one of the most powerful in recent memory. A recent paper shows that seismic waves were released 15 minutes before the eruption and before any visible disruption at the surface. The waves had been detected by a seismic station 750km away. This is the first time a precursor signal has been detected.

November 17, 2024November 17, 2024 by Mark Thompson

James Webb Confirms Hubble’s Calculation of Hubble’s Constant

Artist impression of the James Webb Space Telescope

We have been spoiled over recent years with first the Hubble Space Telescope (HST) and then the James Webb Space Telescope (JWST.) Both have opened our eyes on the Universe and made amazing discoveries. One subject that has received attention from both is the derivation of the Hubble Constant – a constant relating the velocity of remote galaxies and their distances. A recent paper announces that JWST has just validated the results of previous studies by the Hubble Space Telescope to accurately measure its value.

November 17, 2024November 17, 2024 by Mark Thompson

What Should Light Sails Be Made Out Of?

The Breakthrough Starshot program aims to cross the immense distances to the nearest star in just decades. Using a high-powered laser to propel a reflective sail technology to relativistic speeds is their mission. The selection of sail material is key to its success as it must be lightweight while being able to withstand acceleration and radiation from the laser. A recent study explores various materials and proposes that core-shell structures—spherical particles composed of two different materials—could be a promising solution.

November 17, 2024November 17, 2024 by Mark Thompson

A Giant Meteorite Impact 3.26 Billion Years Ago Helped Push Life Forward

Rock and thin section images of the Bruce’s Hill and Umbaumba sections.

The Earth has always been bombarded with rocks from space. It’s true to say though that there were more rocks flying around the Solar System during earlier periods of its history. A team of researchers have been studying a meteorite impact from 3.26 billion years ago. They have calculated this rock was 200 times bigger than the one that wiped out the dinosaurs. The event would have triggered tsunamis mixing up the oceans and flushing debris from the land. The newly available organic material allowed organisms to thrive.

November 16, 2024November 16, 2024 by Mark Thompson

Millions of Phones Could Map the Earth’s Ionosphere

Ionospheric VTEC from phones during a geomagnetic storm

We are all familiar with the atmosphere of the Earth and part of this, the ionosphere, is a layer of weakly ionized plasma. It extends from 50 to 1,500 km above the planet. It’s a diffuse layer but sufficient to interfere with satellite communications and navigation systems too. A team of researchers have come up with an intriguing idea to utilise millions of mobile phones to help map the ionosphere by relying on their GPS antennas.

November 14, 2024November 14, 2024 by Mark Thompson

Interferometry Will Be the Key to Resolving Exoplanets

The setting Sun dips below the horizon of the Pacific Ocean, bathing the Paranal platform in light in this amazing aerial image from the Atacama Desert in northern Chile. The Cerro Paranal mountain top is home to the world’s most advanced ground-based facility for astronomy, hosting the four 8.2-metre Unit Telescopes of the Very Large Telescope, four 1.8-metre Auxiliary Telescopes and the VLT Survey Telescope (VST) — all of which are visible in this image. The 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA), also housed at Cerro Paranal, is hidden out of frame.

When it comes to telescopes, bigger really is better. A larger telescope brings with it the ability to see fainter objects and also to be able to see more detail. Typically we have relied upon larger and larger single aperture telescopes in our attempts to distinguish exoplanets around other stars. Space telescopes have also been employed but all that may be about to change. A new paper suggests that multiple telescopes working together as interferometers are what’s needed.

November 14, 2024November 14, 2024 by Mark Thompson

Why are Some Quasars So Lonely?

This image, taken by NASA’s James Webb Space Telescope, shows an ancient quasar (circled in red) with fewer than expected neighboring galaxies (bright spheres), challenging physicists’ understanding of how the first quasars and supermassive black holes formed. Credits:Credit: Christina Eilers/EIGER team

At the centre of most galaxies are supermassive black holes. When they are ‘feeding’ they blast out jets of material with associated radiation that can outshine the rest of the galaxy. These are known as quasars and they are usually found in regions where huge quantities of gas exist. However, a recent study found a higher than expected number of quasars that are alone in the Universe. These loners are not surrounded by galaxies nor a supply of gas. The question therefore remains, how are they shining so brightly.

November 13, 2024November 13, 2024 by Mark Thompson

How Life Could Live Under the Ice on Mars

Water ice in a Martian gully. This image, showing part of a region called Dao Vallis, was captured by NASA’s Mars Reconnaissance Orbiter in 2009. Credit: NASA/JPL-Caltech/University of Arizona

Mars has been a fascination to us for centuries. Early observations falsely gave impressions of an intelligent civilisation but early visiting probes revealed a stark, desolate world. Underneath the surface is a few metres of water ice and a recent study by NASA suggests sunlight could reach the layer. If it does, it may allow photosynthesis in the meltwater. On Earth this actually happened and biologists have found similar pools teeming with life.

November 12, 2024November 12, 2024 by Mark Thompson

Early Black Holes Fed 40x Faster than Should Be Possible

This artist’s illustration shows a red, early-Universe dwarf galaxy that hosts a rapidly feeding black hole at its center. Using data from NASA's JWST and Chandra X-ray Observatory, a team of U.S. National Science Foundation NOIRLab astronomers have discovered this low-mass supermassive black hole at the center of a galaxy just 1.5 billion years after the Big Bang. It is accreting matter at a phenomenal rate — over 40 times the theoretical limit. While short lived, this black hole’s ‘feast’ could help astronomers explain how supermassive black holes grew so quickly in the early Universe.

The theory goes that black holes accrete material, often from nearby stars. However the theory also suggests there is a limit to how big a black hole can grow due to accretion and certainly shouldn’t be as large as they are seen to be in the early Universe. Black holes it seems, are fighting back and don’t care about those limits! A recent study shows that supermassive black holes are growing at rates that defy the limits of current theory. Astronomers just need to figure out how they’re doing it!