Scott Alan Johnston, Author at Universe Today

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.

April 30, 2021April 30, 2021 by Scott Alan Johnston

China Launches the Core Module of Its New Space Station

Early on Thursday, a Long March 5B rocket – currently the most powerful of China’s space launch vehicles – blasted off from Wenchang, carrying the first major component of an ambitious new modular space station.

The station module, dubbed Tianhe (Harmony of the Heavens), marks the next big step in China’s human spaceflight program in Low Earth Orbit (LEO). Barred from participating in the International Space Station (ISS) by US law, which forbids cooperation in space between the two countries, China has been developing its own LEO capabilities for over a decade now.

April 23, 2021April 23, 2021 by Scott Alan Johnston

Perseverance Successfully Extracts Oxygen From the Martian Atmosphere. About 10 Minutes of Breathing Time for an Astronaut

Humanity achieved an incredible series of new milestones on Mars this week. It began on Monday April 19th, when the Ingenuity helicopter demonstrated the first-ever powered, controlled flight on another world. And now, for the first time, the Perseverance rover has used ingredients from the Martian atmosphere to create breathable oxygen, in a test that might pave the way for future astronauts to ‘live off the land’ on the Red Planet.

April 17, 2021April 17, 2021 by Scott Alan Johnston

When Stars Get Too Close to Each Other, They Cast Out Interstellar Comets and Asteroids

Artist’s impression of the first interstellar asteroid/comet, "Oumuamua". This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

In October 2017, humanity caught its first-ever glimpse of an interstellar object – a visitor from beyond our solar system – passing nearby the Sun. We named it Oumuamua, and its unusual properties fascinated and confounded astronomers. Less than two years later, amateur astronomer Gennady Borisov found a second interstellar object: a comet-like body that began to disintegrate as it passed within 2 AU of the Sun (1 AU equals the distance from Earth to the Sun). Where do these interstellar objects come from? How common are they? With a sample size of just two, it’s difficult to make any generalizations just yet. On the other hand, given what we know about star formation, we can begin to make some inferences about the likely origins of these objects, and what we are likely to see of them in the future.

April 15, 2021April 15, 2021 by Scott Alan Johnston

Ground-Based Lasers Could Push Space Debris off Collision-Course Orbits

Researchers at the Australian National University (ANU) are finding new uses for the laser-based technology that sharpens telescope imagery – called adaptive optics – and it just might help mitigate the world’s growing space debris problem. Purpose-built lasers could give derelict satellites a slight ‘push’ of photons, imparting just enough energy to change the debris’s orbit and prevent an impending collision.

April 12, 2021April 12, 2021 by Scott Alan Johnston

OSIRIS-REx Did One Last Close Flyby of Asteroid Bennu. It’s Almost Time to Come Home

After more than two years in orbit around asteroid Bennu, NASA’s OSIRIS-REx spacecraft is ready to come home. It’s bringing with it a pristine sample of space rocks that geologists here on Earth are eager to study up close. The sample will arrive in September 2023, but we won’t have to wait nearly that long for new data from OSIRIS-REx. Last week, the probe carried out one final flyby of Bennu, in an effort to photograph the sample collection site. The photographs are being downlinked now, and should be here by midweek.

If you’ve been following the OSIRIS-REx mission, you probably already know why scientists are keen to see these photographs, but if you haven’t, hold on to your hats – it’s a wild story.

April 9, 2021April 9, 2021 by Scott Alan Johnston

Jupiter Could Make an Ideal Dark Matter Detector

NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill (wikimedia commons)

So, you want to find dark matter, but you don’t know where to look? A giant planet might be exactly the kind of particle detector you need! Luckily, our solar system just happens to have a couple of them available, and the biggest and closest is Jupiter. Researchers Rebecca Leane (Stanford) and Tim Linden (Stockholm) released a paper this week describing how the gas giant just might hold the key to finding the elusive dark matter.

April 4, 2021April 4, 2021 by Scott Alan Johnston

InSight Detects Two Significant Quakes from the Cerberus Fossae Region on Mars

NASA’s InSight lander felt the distant rumble of two major ‘marsquakes’ in March, originating from a region near the Martian equator known as the Cerberus Fossae. Registering magnitudes of 3.1 and 3.3 on March 7th and March 18th respectively, the quakes cement the Cerberus Fossae’s reputation as one of the most geologically active places on the Red Planet today. A pair of similarly strong marsquakes rocked the same region back in 2019.

March 26, 2021March 26, 2021 by Scott Alan Johnston

Newly Forming Stars Don’t Blast Away Material as Previously Believed. So Why Do They Stop Growing?

We thought we understood how stars are formed. It turns out, we don’t. Not completely, anyway. A new study, recently conducted using data from the Hubble Space Telescope, is sending astronomers back to the drawing board to rewrite the accepted model of stellar formation.

March 25, 2021March 25, 2021 by Scott Alan Johnston

A Very Powerful Solar Storm Hit the Earth Back in 1582

Earth's magnetosphere is the region defined by our planet's magnetic field. Image Credit: NASA

“A great fire appeared in the sky to the North, and lasted three nights,” wrote a Portuguese scribe in early March, 1582. Across the globe in feudal Japan, observers in Kyoto noted the same fiery red display in their skies too. Similar accounts of strange nighttime lights were recorded in Leipzig, Germany; Yecheon, South Korea; and a dozen other cities across Europe and East Asia.

It was a stunning event. While people living at high latitudes were well aware of auroras in 1582, most people living closer to the equator were not. The solar storm that year was unlike anything in living memory, and it was so strong it brought the aurora to latitudes as low as 28 degrees (in line with Florida, Egypt, and southern Japan). People this close to the equator had no frame of reference for such dazzling nighttime displays, and many took it as a religious portent.