Scott Alan Johnston, Author at Universe Today

October 17, 2021October 17, 2021 by Scott Alan Johnston

Did Titan Give Saturn its Tilt?

Giant planets like Saturn don’t just tilt over all by themselves: something has to knock them over, or tug on them gravitationally, to push them off axis. Scientists expect that when new planets are born, they form with almost no tilt at all, lining up like spinning tops, with their equators level to the orbital plane in which they circle around their sun.

But no planet in our solar system is perfectly level. Jupiter is the closest, boasting an obliquity (tilt) of just 3.12 degrees. Earth’s obliquity is much more substantive at 23.45 degrees, causing us to experience an annual cycle of seasons as our homeworld wobbles on its axis. Saturn’s tilt is more extreme yet, with an obliquity of 26.73 degrees (though it’s nowhere near as extreme as Uranus, which is practically sideways, spinning at a 97.86-degree angle to its orbital plane).

We can learn a lot from these obliquities.

October 7, 2021October 7, 2021 by Scott Alan Johnston

Perseverance Sees Evidence of Flash Floods in Jezero Crater

Nearly eight months into the Perseverance rover’s mission on Mars, researchers have confirmed that Jezero crater is (as was believed) an ancient lakebed, but more significantly, that it once experienced powerful flash floods that pushed boulders from tens of miles upstream into the crater basin.

October 3, 2021October 3, 2021 by Scott Alan Johnston

When Did Photosynthesis Begin?

Sometime around 2.4 billion years ago, a nascent planet Earth underwent one of the most dramatic changes in its history. Known as the Great Oxidation Event, this period saw Earth’s atmosphere suddenly bloom with (previously scarce) molecular oxygen. The rapid alteration of the atmosphere’s composition was nothing short of a cataclysm for some early lifeforms (at the time, mostly simple celled prokaryotes). Anaerobic species – those that dwell in oxygen-free environments – experienced a near extinction-level event. But the Great Oxidation was also an opportunity for other forms of life to thrive. Oxygen in the atmosphere tempered the planetary greenhouse effect, turning methane into the less potent carbon dioxide, and ushering in a series of ice ages known as the Huronian Glaciation. But oxygen is an energy-rich molecule, and it also bolstered diversity and activity on the planet, as a powerful new source of fuel for living organisms.

The cause of this dramatic event? The tiniest of creatures: little ocean-dwelling cyanobacteria (sometimes known as blue-green algae) that had developed a new super-power never before seen on planet Earth: photosynthesis. This unique ability – to gain energy from sunlight and release oxygen as a waste product – was a revolutionary step for so small a critter. It quite literally changed the world.

September 25, 2021September 25, 2021 by Scott Alan Johnston

A Tiny, Inexpensive Satellite Will be Studying the Atmospheres of hot Jupiters

The Colorado Ultraviolet Transit Experiment (aptly nicknamed CUTE) is a new, NASA-funded mission that aims to study the atmospheres of massive, superheated exoplanets – known as hot Jupiters – around distant stars. The miniaturized satellite, built by the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder, is set to launch this Monday, September 27th on an Atlas V rocket.

September 19, 2021September 19, 2021 by Scott Alan Johnston

Astronomers See Carbon-Rich Nebulae Where Planets are Forming

Understanding the birth of a planet is a challenging puzzle. We know that planets form inside clouds of gas and dust that surround new stars, known as protoplanetary disks. But grasping exactly how that process works – connecting the dots between a dust cloud and a finished planet – is not easy. An international team of astronomers is attempting to unlock some of those secrets, and have recently completed the most extensive chemical composition mapping of several protoplanetary discs around five young stars. Their research allows them to begin to piece together the chemical makeup of future exoplanets, offering a glimpse into the formation of new alien worlds.

September 12, 2021September 12, 2021 by Scott Alan Johnston

Researchers Create the Most Powerful Magnet Ever Made on Earth: 20 Teslas

On September 5, 2021, a team of MIT researchers successfully tested a high-temperature superconducting magnet, breaking the world record for the most powerful magnetic field strength ever produced. Reaching 20 Teslas (a measure of field intensity), this magnet could prove to be the key to unlocking nuclear fusion, and providing clean, carbon-free energy to the world.

August 29, 2021August 29, 2021 by Scott Alan Johnston

After Its Last Rock Sample Crumbled Into Powder, Perseverance is Going to try Again

In the last two decades, we have all grown accustomed to rovers exploring Mars. At least one rover has been active on the planet every day since January 4, 2004, when NASA’s Spirit rover landed in Gusev crater. Opportunity (2004) and Curiosity (2012) followed, each making unique journeys of discovery of their own. Perseverance (2021) is the latest and greatest of these robotic explorers, boasting a state-of-the-art in-situ resource utilization experiment to extract oxygen from the atmosphere, an accompanying helicopter to scout the path ahead, and a suite of unparalleled geology instruments. But what really sets Perseverance’s mission apart is that, for the first time, it is collecting samples of Martian rock to bring back to Earth.

August 25, 2021August 25, 2021 by Scott Alan Johnston

China’s Rover Completes its Primary 90-day Mission, but it Still has More Science to do

Three months after touching down on the Martian surface, China’s Zhurong rover has completed its primary mission and is still going strong.

August 7, 2021August 7, 2021 by Scott Alan Johnston

Light Pollution is Making it Harder for Animals to Find Their Way at Night

Ah, the majestic dung beetle. The pinnacle of evolution. In all seriousness, these little critters are incredibly sophisticated navigators who have, for millennia, used the night sky to guide them about their business. But light pollution is making their lives more difficult by limiting their ability to navigate by the stars. Other nocturnal creatures, including some birds and moths, may be facing similar challenges.

July 24, 2021July 24, 2021 by Scott Alan Johnston

Russia Just Launched a New Science Module to the Space Station

The International Space Station (ISS) is about to get a little bigger.

On July 21, the Russian Space Agency launched the station’s newest module into orbit aboard a Proton-M rocket. The module, dubbed Nauka (which means science), is the station’s first new module since 2016, aside from some new docking ports and airlocks. The Nauka module includes several important additions that will enhance the station’s capabilities.