Astronomy

ESA’s Hera mission for planetary defence has taken its first images using three of the instruments that will be used to explore and study the asteroids Dimorphos and Didymos.

On Oct. 14, 1947, Chuck Yeager smashed the sound barrier in the secret experimental X-1 aircraft.

See what moon phase it is tonight and find out when you can see the rest of the moon phases for 2024.

See the latest updates for the launch of NASA's Europa Clipper to Jupiter's icy moon here.

NASA's first mission to another ocean world in our solar system will launch toward Jupiter today (Oct. 14), but if you want to watch it live, you'll need to know when to tune in.

Perhaps you’ve heard of the popular Netflix show and the science fiction novel on which it is based, The Three-Body Problem, by Chinese science fiction author Liu Cixin. The story’s premise is a star system where three stars orbit each other, which leads to periodic destruction on a planet orbiting one of them. As Isaac Newton described in his Philosophiæ Naturalis Principia Mathematica, the interaction of two massive bodies is easy to predict and calculate. However, the interaction of three bodies leads is where things become unpredictable (even chaotic) over time.

This problem has fascinated scientists ever since and remains one of the most famous unsolved mysteries in mathematics and theoretical physics. The theory states that the interaction of three gravitationally bound objects will evolve chaotically and in a way that is completely detached from their initial positions and velocities. However, in a recent study, an international team led by a researcher from the Niels Bohr Institute ran millions of simulations that showed “isles of regularity in a sea of chaos.” These results indicate that there could be a solution, or at least some predictability, to the Three-Body Problem.

The study was led by Alessandro Alberto Trani, a postdoctoral fellow at the University of Copenhagen’s Niels Bohr Institute (NBI), the Research Center for the Early Universe at The University of Tokyo, and the Okinawa Institute of Science and Technology (OIST). He was joined by researchers from the Universidad de Concepción in Chile, the American Museum of Natural History, the Leiden Observatory, and NASA’s Ames Research Center. The paper that details their findings was recently published in the journal Astronomy & Astrophysics.

Millions of simulations form a rough map of all conceivable outcomes when three objects meet, which is where the isles of regularity appear. Credit: Alessandro Alberto Trani

To investigate this problem, Trani and his colleagues used a software program he developed himself named Tsunami. This program calculates the movements of astronomical objects based on known physical laws, such as Newton’s Law of Universal Gravitation and Einstein’s Theory of General Relativity. They then set it to run millions of simulations of three-body encounters with specified parameters, including the positions of two co-orbiting objects (i.e., their phase along a 360-degree axis) and the angle of approach of the third object – varying by 90°. As Trani explained in a recent NBI Research News story:

“The Three-Body Problem is one of the most famous unsolvable problems in mathematics and theoretical physics. The theory states that when three objects meet, their interaction evolves chaotically, without regularity, and completely detached from the starting point. But our millions of simulations demonstrate that there are gaps in this chaos – ‘isles of regularity’ – which directly depend on how the three objects are positioned relative to each other when they meet, as well as their speed and angle of approach.”

The millions of simulations they conducted covered all possible combinations of this framework. The results formed a rough map of all conceivable outcomes from the threads of initial configurations, which is when the isles of regularity appeared. This discovery could lead to a deeper understanding of an otherwise impossible problem and represents a new challenge for researchers. Whereas it is possible to calculate our chaos using statistical methods, they become more complex when the chaos is interrupted by regularities. Said Trani:

“When some regions in this map of possible outcomes suddenly become regular, it throws off statistical probability calculations, leading to inaccurate predictions. Our challenge now is to learn how to blend statistical methods with the so-called numerical calculations, which offer high precision when the system behaves regularly. In that sense, my results have set us back to square one, but at the same time, they offer hope for an entirely new level of understanding in the long run.”

This illustration shows the merger of two supermassive black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Credit: LIGO/T. Pyle

Since the encounter of three objects in the Universe is a common occurrence, the Three-Body Problem is more than just a theoretical challenge. Trani hopes that this discovery will lead to a deeper understanding that will pave the way for improved astrophysics models:

“If we are to understand gravitational waves, which are emitted from black holes and other massive objects in motion, the interactions of black holes as they meet and merge are essential. Immense forces are at play, particularly when three of them meet. Therefore, our understanding of such encounters could be a key to comprehending phenomena such as gravitational waves, gravity itself and many other fundamental mysteries of the Universe.”

Further Reading: Neils Bohr Institute

The post New Research Could Help Resolve the “Three-Body Problem” appeared first on Universe Today.

The “Epoch of Reionization” was a critical period for cosmic evolution and has always fascinated and mystified astronomers. During this epoch, the first stars and galaxies formed and reionized the clouds of neutral hydrogen that permeated the Universe. This ended the Cosmic Dark Ages and led to the Universe becoming “transparent,” what astronomers refer to as “Cosmic Dawn.” According to our current cosmological models, reionization lasted from 380,000 to 1 billion years after the Big Bang. This is based on indirect evidence since astronomers have been unable to view the Epoch of Reionization directly.

Investigating this period was one of the main reasons for developing the James Webb Space Telescope (JWST), which can pierce the veil of the “dark ages” using its powerful infrared optics. However, observations provided by Webb revealed that far more galaxies existed in the early Universe than previously expected. According to a recent study, this suggests that reionization may have happened more rapidly and ended at least 350 million years earlier than our models predict. Once again, the ability to peer into the early Universe has produced tensions with prevailing cosmological theories.

The study was led by Julian B Muñoz, an assistant professor of astronomy at The University of Texas at Austin. He was joined by John Chisholm, also an assistant professor of astronomy at UT Austin; Jordan Mirocha, a NASA postdoctoral student at NASA’s Jet Propulsion Laboratory and the California Institute of Technology; Steven R Furlanetto, an associate professor of physics and astronomy at the University of California-Los Angeles, and Charlotte Mason, an associate professor with the Cosmic Dawn Center at the Niels Bohr Institute. The paper that describes their findings was published in the Monthly Notices of the Royal Astronomical Society.

The history of the Universe is outlined in this infographic. Credit: NASA

According to current cosmological models, the Universe was filled with a hot, dense plasma of protons and electrons for the first 380,000 years after the Big Bang. Eventually, the Universe cooled enough for protons and electrons to come together and form neutral hydrogen. By ca. 100 million years after the Big Bang, the first stars (Population III) began to form, which were extremely massive and hot. These stars came together to create the first galaxies, and their ultraviolet light caused neutral hydrogen to once again split into protons and electrons (aka. became ionized).

Once most of the hydrogen in the Universe became ionized (ca. 1 billion years after the Big Bang), the Epoch of Reionization ended. At this point, the Universe was transparent, and light from this period is visible to optical telescopes today. As Chisholm indicated in a UT Austin news release, reionization also played a major role in how the Universe evolved. “The process heated and ionized gas in the Universe, which regulated how fast galaxies grew and evolved,” “These early stars established the overall structure of galaxies in the Universe.”

Before the deployment of the JWST, scientists relied on measurements of the Cosmic Microwave Background (CMB), the relic radiation from the Big Bang, and the Lyman-alpha Forest – the wavelength of light associated with hydrogen reionization. From this, astronomers have gained a sense of how much energy was available for reionization to occur (a “photon budget”) and how long it lasted. As Muñoz explained:

“[Reionization] is the last major change to happen. You went from neutral and cold and boring to ionized and hot. And this isn’t something that only happened to one or two galaxies. It happened to the whole Universe. It’s an accounting game. We know that all hydrogen was neutral before reionization. From there, you need enough extreme ultraviolet to split each atom. So, at the end of the day, you can do the math to figure out when reionization ended.”

Cosmic Microwave Background Radiation. Credit: NASA

However, observations made with the JWST have revealed things that challenge accepted models. This includes a greater abundance of galaxies, which produce more UV radiation than previously anticipated. These findings suggest that reionization should have ended 550 to 650 million years after the Big Bang rather than 1 billion years. But if this were true, the CMB and Lyman-alpha Forest would look different. In short, there is a tension between these measurements and Webb‘s observations – as the team describes in their study, a “photon budget crisis.”

Much like the Hubble Tension, these findings suggest something could be missing from our current cosmological models. One possibility that the team explored is recombination, where ionized protons and electrons come together again to form neutral hydrogen. This is precisely what happened 380,000 years after the Big Bang, known as the “Era of Recombination.” If this process happened more often than our models suggest, it could increase the amount of extreme-UV light needed to reionize the Universe. As Muñoz explained, follow-up observations are needed to confirm this theory:

“We need more detailed and deeper observations of galaxies, and a better understanding of the recombination process. Resolving this tension on reionization is a key step to finally understanding this pivotal period. I am excited to see what the coming years hold.”

Further Reading: Phys.org, MNRAS

The post Webb Observations Shed New Light on Cosmic Reionization appeared first on Universe Today.

A bright comet is moving into the evening skies.

Astronomers at the International Astronomical Union report that we have now detected more than 200 gravitational-wave events, most the merger of two black holes.

The post Status Report: Gravitational Waves appeared first on Sky & Telescope.

The Perseids peak on Sunday night, August 11-12 and just might be joined by a colorful display of northern lights. 

The post Tonight's Perseid Meteor Shower May Be Dipped in Aurora Sauce appeared first on Sky & Telescope.

It's time again for the annual August meteor-shower fest, the Perseids. This year's display should be a beauty with only minor moonlight and a special surprise at dawn.

The post Woo-hoo — The Perseid Meteor Shower Is Coming! appeared first on Sky & Telescope.

The Perseid meteor shower peaks late Sunday night August 11th and maybe Monday night too. Jupiter and Mars have a close conjunction on the morning of the 14th, looking radically different in the same telescopic view.

The post This Week's Sky at a Glance, August 9 – 18 appeared first on Sky & Telescope.

The year’s long-awaited Perseid meteor shower will be accompanied by a graceful planetary conjunction. It’s well worth staying up all night to watch.

The post Prepare for the Perseids and a Pretty Planetary Pairing appeared first on Sky & Telescope.

Fifteen years ago, the Hubble Space Telescope gazed intently at the infrared glow of galaxies in a tiny fraction of the sky. New research shows how this patch of space has changed since then.

The post The Hubble Ultra-Deep Field, 15 Years Later appeared first on Sky & Telescope.

New data on the brightest pulsar observed with a telescope on the International Space Station suggests neutron star interiors are "squishy."

The post Neutron Stars Might Be Squishy Inside appeared first on Sky & Telescope.

Amateur astronomers are all life-long learners — and this "back to school" time of year provides just the right motivation.

The post Enroll in the School of Stars appeared first on Sky & Telescope.

The Perseid meteors ramp up this week to their peak. Saturn is nicely up in the east by late evening. Jupiter and Mars near their conjunction in the morning sky. And there's a story behind Poniatowski's Bull.

The post This Week's Sky at a Glance, August 2 – 11 appeared first on Sky & Telescope.

"Leopard spots" on a Mars rock could come from life — or they could simply be a sign of a type of chemical reaction that requires water.

The post Does This Mars Rock Show a "Potential Biosignature"? Or Just "Wet Chemistry"? appeared first on Sky & Telescope.

Let’s go on a night-sky tour of the stars and planets that you’ll see overhead during August. Find a good seat for some great “shooting stars,” watch Saturn climb in the eastern sky in early evening, check out the summer's brightest stars, and start looking for a once-in-your-lifetime star blast. 

The post August Podcast: Nova Watch in the Northern Crown appeared first on Sky & Telescope.

Future funding for NASA's remaining Great Observatories — Chandra X-ray Observatory and Hubble Space Telescope — is still up in the air.

The post Reading the Tea Leaves: The Future of the Hubble and Chandra Space Telescopes appeared first on Sky & Telescope.