INFORMATION

Chinese and Indian astronomers were the first to measure Earth’s axial tilt accurately, and they did it about 3,000 years ago. Their measurements were remarkably accurate: in 1120 BC, Chinese astronomers pegged the Earth’s axial tilt at 24 degrees. Now we know that all of the planets in the Solar System, with the exception of Mercury, have some tilt. While astronomers have puzzled over why our Solar System’s planets are tilted, it turns out it’s rather normal. Now that astronomers have observed so many other solar systems, they’ve learned that axial tilt is to be expected, even in so-called “pristine” solar systems. Pristine refers to the precise mathematical relationship between planets. New research in The Astronomical Journal explains why some axial tilt is to be expected. It’s titled “ Evidence for Low-level Dynamical Excitation in Near-resonant Exoplanet Systems. ” The lead author is Malena Rice, an assistant professor of astronomy at Yale’s Faculty of Arts and Sciences. The ...

Astronomers have imaged dozens of protoplanetary discs around Milky Way stars, seeing them at all stages of formation. Now, one of these discs has been found for the first time — excitingly — in another galaxy. The discovery was made using the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile along with the , which detected the telltale signature of a spinning disc around a massive star in the Large Magellanic Cloud, located 160,000 light-years away. “When I first saw evidence for a rotating structure in the ALMA data I could not believe that we had detected the first extragalactic accretion disc, it was a special moment,” said Anna McLeod, an associate professor at Durham University in the UK and lead author of the study published in Nature. “We know discs are vital to forming stars and planets in our galaxy, and here, for the first time, we’re seeing direct evidence for this in another galaxy.” McLeod and her fellow researchers were doing a follow-up study on a system...

China’s Zhurong rover was equipped with a ground-penetrating radar system, allowing it to peer beneath Mars’s surface. Researchers have announced new results from the scans of Zhurong’s landing site in Utopia Planitia, saying they identified irregular polygonal wedges located at a depth of about 35 meters all along the robot’s journey. The objects measure from centimeters to tens of meters across. The scientists believe the buried polygons resulted from freeze-thaw cycles on Mars billions of years ago, but they could also be volcanic, from cooling lava flows. A wireless camera took this ‘group photo’ of China’s Tianwen-1 lander and rover on Mars’ surface. Credit: Chinese Space Agency The Zhurong rover landed on Mars on May 15, 2021, making China the second country ever to successfully land a rover on Mars. The cute rover, named after a Chinese god of fire, explored its landing site, sent back pictures — including a selfie with its lander, taken by a remote camera – studied the top...

Ever want to play a game of cosmic billiards? That’s commonly how the DART mission was described when it successfully changed the orbit of a near-Earth asteroid last year. If you want an idea of how it works, just Google it and an Easter egg from the search giant will give you a general idea. But DART was more like trying to brute force a billiards break – there are many other things you can do with a set of asteroids and impactors on the galactic stage. One of the more interesting is to try to force two asteroids together to form a “contact binary” – the goal of a mission design put forward by a group of scientists from Cornell in a recent paper in Acta Astronautica. Colby Merill and his colleagues at Cornell’s Mechanical and Aerospace Engineering department first explain why such a mission would be a good idea. Contact binaries are defined as a system when two objects are so close together that their surfaces touch. Typically, astronomers think of the objects as a pair of stars, bu...

Space exploration is always changing. Before February 2021 there had never been a human made craft flying around in the atmosphere of another world (other than rocket propelled landers arriving or departing). The Mars Perseverance rover changed that, carrying with it what can only be described as a drone named Ingenuity.  It revolutionised planetary exploration and now, China are getting in on the act with a proposed quadcopter for a Mars sample return mission. Our exploration of Mars has generally been limited to orbiters, landers and rovers. The orbiters are fantastic at getting planet wide data or data covering huge swathes of land and the landers are great at getting surface detail, even analysing surface material. The rovers added an extra dimension by being able to explore the landing area but generally, the rovers were slow and unable to traverse significant distances. They were also unable to move over very uneven terrain giving them limited capability. Mars Perseveranc...

As our newest, most perceptive eye on the ongoing unfolding of the cosmos, the James Webb Space Telescope is revealing many things that were previously unseeable. One of the space telescope’s science goals is to expand our understanding of how stars form. The JWST has the power to see into the cocoons of gas and dust that hide young protostars. It peered inside one of these cocoons and showed us that what we thought was a single star is actually a binary star. The JWST’s image of the Herbig Haro object 797 (HH 797) is the telescope’s Picture of the Month . Herbig-Haro objects are luminous patches of nebulosity associated with young protostars. These stars are still gathering mass, a stage that can last about 500,000 years. As the protostar gathers mass, in-falling gas generates shocks on the star’s surface. So, while protostars haven’t begun their life of fusion, they still release energy. In a Herbig-Haro object, the energy that lights it up comes from twin jets of ionized gas co...

In 1950, while sitting down to lunch with colleagues at the Los Alamos Laboratory, famed physicist and nuclear scientist Enrico Fermi asked his famous question: “ Where is Everybody? ” In short, Fermi was addressing the all-important question that has plagued human minds since they first realized planet Earth was merely a speck in an infinite Universe. Given the size and age of the Universe and the way the ingredients for life are seemingly everywhere in abundance, why haven’t we found any evidence of intelligent life beyond Earth? This question has spawned countless proposed resolutions since Fermi’s time, including the infamous Hart-Tipler Conjecture (i.e., they don’t exist). Other interpretations emphasize how space travel is hard and extremely time and energy-consuming, which is why species are likely to settle in clusters (rather than a galactic empire) and how we are more likely to find examples of their technology (probes and AI) rather than a species itself. In a recent study...

“Oh My God,” someone must have said in 1991 when researchers detected the most energetic cosmic ray ever to strike Earth. Those three words were adopted as the name for the phenomenon: the Oh-My-God particle. Where did it come from? Some unknown, extraordinarily powerful event out there in the cosmos sent this single particle all the way to Earth as a signal of its occurrence. Nobody knows where it came from nor what type of particle Oh-My-God was. Cosmic rays are typically protons; whatever this particle was, it was extraordinarily energetic. It had 40 million times more energy than anything scientists have propelled in any particle accelerator: about 320 million TeV ( tera electron volts .) The University of Utah Fly’s Eye detected the Oh-My-God Particle (OMGP). The same facility detected many more cosmic rays, but none approaching the OMGP’s energy. Now, researchers have detected another ultra-energetic cosmic ray. It was detected with the Telescope Array Project , another ul...

Ripples in a pond can be captivating on a nice sunny day as can ripples in the very fabric of space, although the latter are a little harder to observe.  Using the highly tuned Gaia probe, a team of astronomers propose that it might just be possible to detect gravitational waves through the disturbance they impart on the movement of asteroids in our Solar System! In the teaser I said that gravitational waves were difficult to observe, largely because they are invisible and incredibly fast, travelling at the speed of light (approximately 300,000 km per second). Despite the challenge in observing them, the first waves were detected in 2015 using the Laser Interferometer Gravitational-Wave Observatory or LIGO for short.  LIGO Observatory from above (Credit : LIGO Observatory) Let’s go back a little first though. It was Einstein who first suggested that an event in the Universe that exhibited movement; perhaps two objects orbiting each other or a star exploding might generat...

Some stars are stuck in bad binary relationships. A massive primary star feeds on its smaller companion, sucking gas from the companion and adding it to its own mass while diminishing its unfortunate partner. These vampire stars are called Be stars, and up until now, astronomers thought they existed in binary relationships. But new research shows that these stars are only able to feed on their diminutive neighbour because of a third star present in the system. Be stars are a sub-type of B stars . B is the stars’ spectral type, so both B and Be stars share the same type. Both types are luminous and blue, but while B stars can be from 2-16 times as massive as the Sun, Be stars aren’t as massive. Be stars also rotate more rapidly than other stars, and have accretion rings. About 20% of B stars are Be stars. Be stars are important in our quest to understand how stars form and evolve. Astronomers have known about Be stars for a long time, but their formation mechanism has been uncertain...

When a spacecraft dies, it loses the ability to maintain its direction in space. Additionally, as the spacecraft’s orbit begins to decay, the thin atmosphere interacts with the spacecraft, causing it to tumble unpredictably. ESA’s Clean Space Initiative hopes to remove the most hazardous space debris. This means capturing dead satellites that are in a death spiral. To help begin the project Researchers observed over 20 objects in space over two year and then recreated their spin to develop plans to retrieve them. Retrieving a tumbling spacecraft will require a brave robot to take on the task! This illustration depicts the Kessler Syndrome, named after American astrophysicist Donald Kessler, where collisions produce more debris that leads to a growing cascade of collisions that ultimately makes Earth orbit unusable. In 2012, Kessler co-authored an article warning that we’re already at the tipping point. Image Credit: ESA It is estimated that there are 130 million pieces of space d...

When spacecraft return to Earth, they don’t need to shed all their velocity by firing retro-rockets. Instead, they use the atmosphere as a brake to slow down for a soft landing. Every planet in the Solar System except Mercury has enough of an atmosphere to allow aerobraking maneuvers, and could allow high-speed exploration missions. A new paper looks at the different worlds and how a spacecraft must fly to take advantage of this “free lunch” to slow down at the destination. Aerobraking uses repeated dips into the atmosphere – i.e., atmospheric drag — to gradually slow the spacecraft and reduce the size of the orbit to achieve orbit insertion. This technique was first used by the Magellan mission to Venus in 1993, and has also been used on several Mars missions, including the Mars Reconnaissance Orbiter (MRO) in 2006. While aerobraking takes time, it saves on the amount fuel required. In MRO’s case, aerobraking reduced the fuel needed by 600 kilograms (1,300 pounds). The new paper, b...