Astronomy Archives

April 25, 2021April 25, 2021 by Brian Koberlein

A new Technique Could use Quasars to Directly Measure the Expansion Rate of the Universe

an artistic concept of a quasar — Concept image of a galactic quasar. Astronomers used the Event Horizon Telescope to study details at the heart of one like this called NRAO 530. Credit: ParallelVision, Pixabay

One of the biggest challenges to measuring the expansion of the universe is the fact that many of the methods we use are model-dependent. The most famous example is the use of distant supernovae, where we compare the standard brightness of a Type Ia supernova with their apparent brightness to find their distance. But knowing the standard brightness depends upon comparing them to the brightness of Cepheid variables which is in turn determined by measuring the distances of nearby stars via parallax. Every step of this cosmic distance ladder depends upon the step before it.

April 24, 2021April 24, 2021 by Matt Williams

Animation Shows how Saturn’s Rings Move at Different Speeds

Saturn's F ring is extremely narrow compared to the historic A, B and C rings. It measure just a few hundred kilometers across. Credit: NASA/Cassini

Saturn’s rings are one of the most recognized and revered celestial objects known to the human race. From a distance, they look like a disk of layered crystal or multicolored disks within disks that wrap around Saturn’s hazy umber face. When viewed up close, we see that these rings are actually particles of water ice (from microns to icebergs), as well as silicates, carbon dioxide, and ammonia.

We would also noticed that the rings have some interesting orbital mechanics. In fact, each ring has a different orbit that is the result of its proximity to Saturn (i.e., the closer they are, the faster they orbit). To illustrate what this complex system look like, NASA Fellow Dr. James O’Donoghue created a stunning animation that shows how each of Saturn’s major ring segments (A-Ring to F-Ring) orbit together around the planet.

April 23, 2021April 23, 2021 by Matt Williams

A Recent Megaflare Shows that Proxima Centauri is not a Nice Place to Live

An artist's conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate atmospheres of nearby planets. Credit: NRAO/S. Dagnello.

Proxima b, the closest exoplanet to our Solar System, has been a focal point of scientific study since it was first confirmed (in 2016). This terrestrial planet (aka. rocky) orbits Proxima Centauri, an M-type (red dwarf) star located 4.2 light-years beyond our Solar System – and is a part of the Alpha Centauri system. In addition to its proximity and rocky composition, it is also located within its parent star’s habitable zone (HZ).

Until a mission can be sent to this planet (such as Breakthrough Starshot), astrobiologists are forced to postulate about the possibility that life could exist there. Unfortunately, an international campaign that monitored Proxima Centauri for months using nine space- and ground-based telescopes recently spotted an extreme flare coming from the star, one which would have rendered Proxima b uninhabitable.

April 21, 2021April 21, 2021 by David Dickinson

Catch Comet R4 ATLAS as it Nears Earth

The coming weeks are a great time to catch comet C/2020 R4 ATLAS… while you can.

Looking to do some springtime astronomy? With temperatures warming up in the northern hemisphere in April through May, galaxy season is upon us. At dusk, the area in the Bowl of Virgo asterism rising in the east is rife with clusters of galaxies that spill over into the adjacent constellations of Coma Berenices and Boötes…

But this May, keep an eye out for a fuzzball interloper that is not a galaxy: Comet C/2020 R4 ATLAS.

April 19, 2021April 19, 2021 by Ralph Crewe

This Is a Collapsed Pit on Mars, Not a Pimple

A HiRISE image of the southern polar region of Mars shows a sunken pit on the layered surface. Credit: NASA/JPL/University of Arizona

Mars has been in the news a lot lately, and for good reason. With the historic landing of the Perseverance Rover earlier in the year, and the successful flight of Ingenuity, the first-ever aircraft to fly in another atmosphere, earlier this morning (April 19, 2021), there’s no shortage of exciting stories of technical brilliance from the human-built wonders exploring the red planet. High above the plucky helicopter, the Mars Reconnaissance Orbiter (MRO) surveys the Martian landscape on a grand scale. A brain-bending image released by High Resolution Imaging Science Experiment (HiRISE), a powerful camera aboard MRO, shows a sunken pit in the planet’s polar region. From the high-altitude perspective of the orbiter, it’s easy for the mind to warp the concave depression into a convex, acne-esque Martian polar zit!

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 14, 2021April 14, 2021 by Matt Williams

If you Want to Move an Asteroid, you Need the Right Kind of Nuclear Explosion

Artist's concept of a large asteroid passing by the Earth-Moon system. Credit: A combination of ESO/NASA images courtesy of Jason Major/Lights in the Dark.

Using nuclear devices to deflect or disrupt an asteroid. Sounds a bit crazy, no? Maybe a little too Hollywood? And yet, detonating nukes in space may be necessary someday for the sake of planetary defense. In order for this method to be effective, scientists need to work out all the particulars in advance. That means knowing how much force will be necessary depending on the mass and trajectory of the asteroid.

Recently, a research collaboration between Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) investigated how the energy output of a nuclear detonation could affect the path of an asteroid. This consisted of modeling different nuclear reactions (fission or fusion) to determine the neutron energy generated, which could potentially pave the way for a new type of asteroid redirect mission (ARM).

April 14, 2021April 15, 2021 by David Dickinson

Galileo Sunspot Sketches Versus Modern ‘Deep Learning’ AI

A new study turns modern ‘deep learning’ techniques on Galileo’s early sketches of the Sun.

It’s a fascinating thought to consider.

What exactly did the Sun look like, centuries ago? What would we see, if astronomers back in the time of Kepler and Galileo had modern technology monitoring the Sun across the electromagnetic spectrum, available to them?

April 12, 2021April 12, 2021 by Matt Williams

The Same Technology Could Search for Microbes in Mars Rocks or Under the ice on Europa

Ever since it landed in the Jezero Crater on Feb. 18^th, 2021, the Perseverance rover has been prepping its scientific instruments to begin searching for signs of past life on the Red Planet. These include spectrometers that will scan Martian rocks for organics and minerals that form in the presence of water and a caching system that will store samples of Martian soil and rock for retrieval by a future mission.

These telltale indicators could be signs of past life, which would most likely take the form of fossilized microbes. In the near future, a similar instrument could be used to search for present-day extraterrestrial life. It’s known as the Wireline Analysis Tool for the Subsurface Observation of Northern ice sheets (WATSON), and could be used to find evidence of life inside “ocean worlds” like Europa, Enceladus, and Titan.