Astronomy Archives

December 15, 2021December 15, 2021 by Matt Williams

A Sun-Like Star Just Blasted out a Flare That Would be Devastating if it Happened Here

In the search for “potentially-habitable” extrasolar planets, one of the main things scientists look at is stellar activity. Whereas stars like our own, a G-type (G2V) yellow dwarf, are considered stable over time, other classes are variable and prone to flare-ups – particularly M-type red dwarf stars. Even if a star has multiple planets orbiting within its habitable zone (HZ), the tendency to periodically flare could render these planets completely uninhabitable.

According to a new study, stars like our own may not be as stable as previously thought. While observing EK Draconis, a G1.5V yellow dwarf located 110.71 light-years away, an international team of astronomers witnessed a massive coronal mass ejection that dwarfed anything we’ve ever seen in our Solar System. These observations suggest that these ejections can worsen over time, which could be a dire warning for life here on Earth.

December 14, 2021December 14, 2021 by Paul M. Sutter

Astronomy Jargon 101: Absolute Magnitude

Taken with the HAWK-I instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert, this stunning image shows the Milky Way’s central region with an angular resolution of 0.2 arcseconds. This means the level of detail picked up by HAWK-I is roughly equivalent to seeing a football (soccer ball) in Zurich from Munich, where ESO’s headquarters are located. The image combines observations in three different wavelength bands. The team used the broadband filters J (centred at 1250 nanometres, in blue), H (centred at 1635 nanometres, in green), and Ks (centred at 2150 nanometres, in red), to cover the near infrared region of the electromagnetic spectrum. By observing in this range of wavelengths, HAWK-I can peer through the dust, allowing it to see certain stars in the central region of our galaxy that would otherwise be hidden.

In this series we are exploring the weird and wonderful world of astronomy jargon! You’ll surely measure the awesomeness of today’s topic: absolute magnitude!

December 14, 2021December 14, 2021 by Matt Williams

Twin Stars Prove Einstein at Least 99.99% Right

Artistic impression of the Double Pulsar system, where two active pulsars orbit each other in just 147 min. The orbital motion of these extremely dense neutrons star causes a number of relativistic effects, including the creation of ripples in spacetime known as gravitational waves. The gravitational waves carry away energy from the systems which shrinks by about 7mm per days as a result. The corresponding measurement agrees with the prediction of general relativity within 0.013%. The picture at high resolution and two alternative versions (1b, 1c) are accessible in the left column. [less] © Michael Kramer/MPIfR

More than a hundred years have passed since Einstein formalized his theory of General Relativity (GR), the geometric theory of gravitation that revolutionized our understanding of the Universe. And yet, astronomers are still subjecting it to rigorous tests, hoping to find deviations from this established theory. The reason is simple: any indication of physics beyond GR would open new windows onto the Universe and help resolve some of the deepest mysteries about the cosmos.

One of the most rigorous tests ever was recently conducted by an international team of astronomers led by Michael Kramer of the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany. Using seven radio telescopes from across the world, Kramer and his colleagues observed a unique pair of pulsars for 16 years. In the process, they observed effects predicted by GR for the first time, and with an accuracy of at least 99.99%!

December 13, 2021December 13, 2021 by Evan Gough

Even Really Massive Stars Seem to Have Planets

This artist’s impression shows a close up of the planet b Centauri b, which orbits a binary system with mass at least six times that of the Sun. This is the most massive and hottest planet-hosting star system found to date. The planet is ten times as massive as Jupiter and orbits the two-star system at 100 times the distance Jupiter orbits the Sun. Image: ESO/L. Calçada

Can planets form around massive, hot stars? Some astronomers think they can’t. According to the evidence, planets around stars exceeding three solar masses should be rare, or maybe even non-existent. But now astronomers have found one.

A team of researchers found a binary star that’s six times the mass of the Sun. And it hosts a planet that’s about ten times more massive than Jupiter.

December 10, 2021December 10, 2021 by Tammy Plotner

The Constellation Fornax

Welcome to another edition of Constellation Friday! Today, in honor of the late and great Tammy Plotner, we take a look at “the Furnace” – the Fornax constellation. Enjoy!

In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of the then-known 48 constellations. This treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come, effectively becoming astrological and astronomical canon until the early Modern Age. This list has since come to be expanded to include the 88 constellation that are recognized by the International Astronomical Union (IAU) today.

Among the updated list is the constellations Fornax, a relatively obscure constellation in the southern sky that is noted for the many bright galaxies it is associated with (the Fornax Cluster). This constellation was added French astronomer Nicolas Louis de Lacaille in the mid-18th century and is therefore part of the Lacaille family, which includes with Antlia, Caelum, Circinus, Horologium, Mensa, Microscopium, Norma, Octans, Pictor, Reticulum, Sculptor, and Telescopium.

December 10, 2021December 10, 2021 by Matt Williams

Galaxies Have Been Found With no Dark Matter at all

This image shows the sky around the ultra diffuse galaxy NGC 1052-DF2. It was created from images forming part of the Digitized Sky Survey 2. NGC 1052-DF2 is basically invisible in this image. It is located to the southwest of the bright elliptical galaxy NGC 1052, which is dominating the field of view, and east of the bright red star HD 16873. Credit: ESA/Hubble, NASA, Digitized Sky Survey 2 Acknowledgement: Davide de Martin

One of the greatest cosmological mysteries facing astrophysicists today is Dark Matter. Since the 1960s, scientists have postulated that this invisible mass accounts for most of the matter in the Universe. While there are still many unresolved questions about it – i.e., What is it composed of? How do we detect it? What evidence is there beyond indirect detection? – we have managed to learn a few things about it over time.

For example, astrophysicists have observed that Dark Matter played a vital role in the formation of galaxies and is responsible for keeping them gravitationally bound. However, when an international team of astronomers observed the ultra-diffuse galaxy AGC 114905, they found no evidence of Dark Matter at all. If these observations are accurate, this discovery could force scientists to reevaluate their cosmological models and the way we look at the Universe.

December 10, 2021December 10, 2021 by David Dickinson

Brrrr: Bundle Up For the 2021 Geminid Meteors

One of the best annual meteor showers of the year, the Geminids top off 2021.

Ready to brave the cold? If you’re like us, you haven’t wasted an early clear sky morning to get out and see Comet C/2021 A1 Leonard before it heads southward. The coming days offer another early AM celestial sight: the Geminid meteors. To be sure, 2021 sees the Geminid meteors transpire under somewhat challenging conditions. But fear not: with a little planning and patience, you too can witness the ‘Tears of the Twins.’

December 9, 2021December 9, 2021 by Matt Williams

Hubble is Fully Operational Once Again

The Hubble Space Telescope hovers at the boundary of Earth and space in this picture, taken after Hubble's second servicing mission in 1997.

In the history of space exploration, a handful of missions have set new records for ruggedness and longevity. On Mars, the undisputed champion is the Opportunity rover, which was slated to run for 90 days but remained in operation for 15 years instead! In orbit around Mars, that honor goes to the 2001 Mars Odyssey, which is still operational 20 years after it arrived around the Red Planet.

In deep space, the title for the longest-running mission goes to the Voyager 1 probe, which has spent the past 44 years exploring the Solar System and what lies beyond. But in Earth orbit, the longevity prize goes to the Hubble Space Telescope (HST), which is once again fully operational after experiencing technical issues. With this latest restoration of operations, Hubble is well on its way to completing 32 years of service.

December 9, 2021December 9, 2021 by Evan Gough

NASA’s New Asteroid Impact Monitoring System Comes Online

This diagram shows the orbits of 2,200 potentially hazardous objects as calculated by JPL’s Center for Near Earth Object Studies (CNEOS). Highlighted is the orbit of the double asteroid Didymos, the target of NASA’s Double Asteroid Redirect Test (DART) mission. Credit: NASA/JPL-Caltech

An asteroid striking Earth is a genuine possibility. There are tens of thousands of asteroids classified as Near-Earth Asteroids (NEAs), and we’re finding around 3,000 more each year. The number of new detections will see an uptick in the next few years as better survey telescopes come online.

Now NASA has developed a new system to classify all those asteroids and better evaluate impact probabilities.

December 9, 2021December 9, 2021 by Andy Tomaswick

Company Tests Iodine Thruster in Space for the First Time

Ion thrusters have played second fiddle to chemical rockets for most of the history of space exploration. Part of that is because of their inability to launch payloads into orbit. But in space, their high thrust-to-weight ratio has plenty of appeal. Other features have held the technology back, including the difficulty of working with the thruster’s fuel source – xenon. Now, a team of engineers and scientists from ThrustMe, a French start-up that focuses on developing advanced propulsions systems, have developed an ion thruster that works on an entirely new and much easier to use material – iodine.