Scott Alan Johnston, Author at Universe Today

July 10, 2021July 10, 2021 by Scott Alan Johnston

Satellite Images Can Help Predict When Underwater Volcanos are About to Erupt

Predicting volcanic eruptions is notoriously tricky. In large part this is because volcanos are unique, each with their own quirks and personalities: the lessons learned from studying one volcano may not apply directly to another. Luckily, researchers are getting better at finding warning signs that they can apply broadly. Some of the most well-known are heightened seismic activity, rising temperatures, expanding magma pools, and the release of gases. New research using satellite imagery now offers a new warning sign for underwater volcanos: a change in the color of the ocean.

July 2, 2021July 2, 2021 by Scott Alan Johnston

A Small Satellite With a Solar Sail Could Catch up With an Interstellar Object

When Oumuamua, the first interstellar object ever observed passing through the Solar System, was discovered in 2017, it exhibited some unexpected properties that left astronomers scratching their heads. Its elongated shape, lack of a coma, and the fact that it changed its trajectory were all surprising, leading to several competing theories about its origin: was it a hydrogen iceberg exhibiting outgassing, or maybe an extraterrestrial solar sail (sorry folks, not likely) on a deep-space journey? We may never know the answer, because Oumuamua was moving too fast, and was observed too late, to get a good look.

It may be too late for Oumuamua, but we could be ready for the next strange interstellar visitor if we wanted to. A spacecraft could be designed and built to catch such an object at a moment’s notice. The idea of an interstellar interceptor like this has been floated by various experts, and funding to study such a concept has even been granted through NASA’s Innovative Advanced Concepts (NIAC) program. But how exactly would such an interceptor work?

June 27, 2021June 27, 2021 by Scott Alan Johnston

LightSail 2 Has Now Been in Space for 2 Years, and Should Last Even Longer Before Re-Entering the Atmosphere

Photo of LightSail 2's sail deployment. Credit: The Planetary Society

The Planetary Society’s crowdfunded solar-sailing CubeSat, LightSail 2, launched on June 25th 2019, and two years later the mission is still going strong. A pioneering technology demonstration of solar sail capability, LightSail 2 uses the gentle push of photons from the Sun to maneuver and adjust its orbital trajectory. Within months of its launch, LightSail 2 had already been declared a success, breaking new ground and expanding the possibilities for future spacecraft propulsion systems. Since then, it’s gone on to test the limits of solar sailing in an ongoing extended mission.

June 13, 2021June 13, 2021 by Scott Alan Johnston

Asteroid 16 Psyche Might Not be a Solid Chunk of Metal After All, but Another Rubble Pile

Asteroid 16 Psyche, often sensationally dubbed the 10,000 quadrillion dollar asteroid due to its composition of valuable metals, may not be entirely what it seems. A new paper out of the University of Arizona suggests that the asteroid is possibly more porous, and less metallic, than previous studies indicated. It still certainly has a mostly metallic structure, but its composition is more complex – and that’s good news. Given the impracticality of space mining (in the near future anyway) 16 Psyche’s real value is scientific: planetary scientists think it is probably the exposed core of a protoplanet from the early days of the Solar System. Studying such an object up close would be enormously useful for understanding planet formation, and this paper is the latest attempt to understand its structure.

June 6, 2021June 6, 2021 by Scott Alan Johnston

Next up, Juno has Ganymede in its Sights

NASA’s Juno mission is set for a close encounter with the Solar System’s largest moon, Ganymede, on Monday. This will be the first flyby of the icy world since the Galileo and Cassini spacecraft jointly observed the moon in 2000. New Horizons also got a quick snap of Ganymede as it slingshotted around Jupiter on its way out to Pluto in 2007, but from a distance of 3.5 million kilometers away. Juno’s pass on Monday will get much closer, approaching within 1038 kilometers of the surface.

May 24, 2021May 24, 2021 by Scott Alan Johnston

Hubble Has Tracked Down the Source of 5 Different Fast Radio Bursts

In a new survey, astronomers using the Hubble Space Telescope have managed to pinpoint the location of several Fast Radio Bursts (FRBs). FRBs are powerful jets of energy that, until recently, had mysterious, unknown origins. The research team, which includes University of California Santa Cruz’ Alexandra Manning and Sunil Simha, as well as Northwestern University’s Wen-fai Fong, performed a survey of eight FRBs, from which they were able to determine that five of them originated from a spiral arm in their host galaxies.

May 20, 2021May 20, 2021 by Scott Alan Johnston

Larger Rocky Planets Might be Rare Because They Shrunk

Researchers at the Flatiron Institute’s Center for Computational Astrophysics published a paper last week that just might explain a mysterious gap in planet sizes beyond our solar system. Planets between 1.5 and 2 times Earth’s radius are strikingly rare. This new research suggests that the reason might be because planets slightly larger than this, called mini-Neptunes, lose their atmospheres over time, shrinking to become ‘super-Earths’ only slightly larger than our home planet. These changing planets only briefly have a radius the right size to fill the gap, quickly shrinking beyond it. The implication for planetary science is exciting, as it affirms that planets are not static objects, but evolving and dynamic worlds.

May 16, 2021May 16, 2021 by Scott Alan Johnston

What’s the Best Way to Water Plants in Space?

Humans have maintained a continuous presence in space on the International Space Station (ISS) for more than 20 years now. It is our longest-running and most comprehensive experiment in long-duration spaceflight. But the ISS is continually supplied with consumables – food, water, and oxygen – so astronauts are largely reliant on Earth. If Humanity is ever going to live and work in space long term, we’re going to have to learn to be more self-reliant – and that means growing food in space.

May 8, 2021May 8, 2021 by Scott Alan Johnston

Volcanoes on Mars Might Still be Active

Back in March, NASA’s InSight lander detected two large quakes from a geologically active region of Mars called the Cerberus Fossae. Now, using imagery from the Mars Reconnaissance Orbiter, which circles the red planet at an altitude of about 300km, researchers have discovered that the Cerberus Fossae region holds the most recent evidence of volcanic activity ever seen on Mars.

May 2, 2021May 2, 2021 by Scott Alan Johnston

Black Hole-Neutron Star Collisions Could Finally Settle the Different Measurements Over the Expansion Rate of the Universe

If you’ve been following developments in astronomy over the last few years, you may have heard about the so-called “crisis in cosmology,” which has astronomers wondering whether there might be something wrong with our current understanding of the Universe. This crisis revolves around the rate at which the Universe expands: measurements of the expansion rate in the present Universe don’t line up with measurements of the expansion rate during the early Universe. With no indication for why these measurements might disagree, astronomers are at a loss to explain the disparity.

The first step in solving this mystery is to try out new methods of measuring the expansion rate. In a paper published last week, researchers at University College London (UCL) suggested that we might be able to create a new, independent measure of the expansion rate of the Universe by observing black hole-neutron star collisions.