Artistic impression of star cluster R136 with runaway stars. Credit: Danielle Futselaar, James Webb Space Telescope/NIRCam - NASA, ESA, CSA and STScI
We live inside the Milky Way galaxy which is joined as it drifts through space by two satellite galaxies, the Magellanic Clouds. A star cluster in the Large Magellanic Cloud known as R136 has been the subject of a fascinating discovery. A team of astronomers have discovered 55 high-speed stars that have been ejected from the cluster. The discovery was made using the Gaia satellite and it seems up to a third of stars from the cluster have been ejected in the last century.
Jupiter is well known for its Great Red Spot, a feature that was discovered by Galileo over 400 years ago! Astronomers have been tracking the size and shape of it for over a century but the most accurate measurements have come from the Hubble Space Telescope. Every time Earth and Jupiter are at their closest, Hubble takes a series of images and it’s these images that have detected that the spot jiggles from day to day. Not only does it change size but length and width too leaving astronomers baffled.
China has released its first national plan for space 2024 and 2050. Credit: CFP
China’s space program has advanced considerably since the turn of the century. In addition to developing heavy-launch vehicles like the Long March 5 and building a modular space station in orbit, China has also embarked on an ambitious program of lunar exploration (Chang’e) – which has launched six robotic missions to explore the Moon’s surface since 2007. These missions are paving the way for crewed missions to the Moon by 2030 and creating a permanent habitat around the Moon’s southern polar region – the International Lunar Research Station (ILRS).
They also plan to send crewed missions to Mars by 2033, which will culminate in the creation of a permanent base there too. Earlier today, the Chinese Academy of Sciences (CAS), the China National Space Administration (CNSA), and the China Manned Space Agency (CMSE) jointly released the country’s first long-term scheme for space science and exploration. Titled “National Medium—and Long-Term Development Plan for Space Science (2024-2050),” this plan elaborated on the basic principles, development goals, and roadmap for the country’s space science and exploration through 2050.
Artist rendering of the X-37B conducting an aerobraking maneuver using the drag of Earth’s atmosphere. Credit: Boeing Space
The X-37B Orbital Test Vehicle (OTV) has been shrouded in mystery since its maiden flight in 2011. Designed by Boeing and operated by the U.S. Space Force (USSF), this remotely operated, reusable space plane is designed to operate in Low-Earth Orbit (LEO), 240 to 800 km (150 to 500 mi) above the Earth, and test reusable vehicle technologies that support long-term space objectives. On December 29th, 2023, the X-37B began its seventh mission (OTV-7) and has reportedly been conducting experiments on the effects of space radiation and testing Space Domain Awareness (SDA) technologies.
As part of this mission, the X-37B will soon begin executing a series of novel maneuvers to change its orbit around Earth. These maneuvers will consist of the spacecraft brushing against Earth’s upper atmosphere to shed speed and lower its orbit without expending much fuel—a technique known as “aerobraking.” This is the first time the X-37B has performed such a maneuver, which will help it evade detection by potentially hostile nations and perform undetected low passes over Earth during future missions.
Ever since the advent of space exploration we have seen some amazing images of the planets. New technology often brings with it a new perspective and we have been reminded of this again just recently with images from the Hubble Space Telescope (HST) and New Horizons spacecraft. The two objects simultaneously imaged Uranus from different perspectives in an attempt to predict what astronomers would see when they look at exoplanets orbiting other stars.
SpaceX's Falcon Heavy rocket sends NASA's Europa Clipper into space from its Florida launch pad. (NASA Photo / Kim Shiflett)
NASA’s Europa Clipper spacecraft today began its six-year cruise to the Jupiter system, with the goal of determining whether one of the giant planet’s moons has the right stuff in the right setting for life.
The van-sized probe was sent into space from NASA’s Kennedy Space Center atop a SpaceX Falcon Heavy rocket at 12:06 p.m. ET (16:06 UTC). A little more than an hour after launch, the spacecraft separated from its launch vehicle to begin a roundabout journey of 1.8 billion miles (2.9 billion kilometers) from Earth orbit to Europa.
For decades, scientists have been collecting evidence that Europa harbors a hidden ocean of salty water beneath its icy shell. Or are they hidden lakes? Europa Clipper is built to characterize the moon’s surface, and what’s beneath that surface, to an unprecedented degree.
This image shows the galaxy REBELS-25 as seen by the Atacama Large Millimeter/submillimeter Array (ALMA), overlaid on an infrared image of other stars and galaxies. Courtesy ESO.
The early Universe continues to offer surprises and the latest observations of infant galaxies are no exception. Astronomers found a surprisingly Milky Way-like galaxy that existed more than 13 billion years ago. That was a time when the Universe was really just an infant and galaxies should still be early in their formation. A well-formed one in such early history is a bit of a surprise.
The newly discovered galaxy is called REBELS-25. It was found as part of the “Reionization Era Bright Emission Line Survey (REBELS) survey using the Atacama Large Millimeter Array (ALMA) in Chile. The idea of the survey is to search out and measure early galaxies.
REBELS-24 is a massive disc-like galaxy with structures that look like spiral arms. That’s pretty similar to our Milky Way Galaxy. It’s more than 13 billion years old and took billions of years to evolve into its present shape. Like REBELS-25, the Milky Way began as a clumpy, disorganized proto-galaxy not long after the Universe began. It merged with other protogalaxies and evolved into a beautiful spiral shape. It appears to be actively forming stars and is incredibly massive for such a young galaxy.
Early Spirals Aren’t New
So, REBELS-25 raises a big question: why is it so massive and well-evolved at a time when the infant Milky Way was still a clump? That’s what astronomers are working to figure out. “According to our understanding of galaxy formation, we expect most early galaxies to be small and messy looking,” said Jacqueline Hodge, an astronomer at Leiden University, the Netherlands. The fact that REBELS-25 looks so “modern” after less than a billion years does—in a sense—rebel against the generally accepted theories about galaxy formation and evolution.
This isn’t the first time that astronomical observations uncovered early spirals. JWST observations suggest that perhaps a third of early galaxies are already spirals in the infant Universe. Its Cosmic Evolution Early Release Science Survey (CEERS) found many of these in the first 700 million years of cosmic history. So, finding this one looking almost “modern” some 13 billion years ago just adds to the mystery of their formation.
REBELS-25 showed up in ALMA observations, which also gave hints that it had a rotating disk. A set of follow-up observations confirmed the rotation of this galaxy and its spiral arm structures. In addition, the ALMA data found hints of a central bar (just like our Milky Way galaxy has). “ALMA is the only telescope in existence with the sensitivity and resolution to achieve this,” said Renske Smit, a researcher at Liverpool John Moores University in the UK and part of the team that worked on this discovery.
The ALMA data produced an image of REBELS-25 (left) and a map of gas motions in this galaxy which lies more than 13 billion light-years away. Blue coloring indicates movement towards Earth. Red indicates movement away from Earth, with a darker shade representing faster movement. In this case, the red-blue divide of the image shows clearly that the object is rotating, making REBELS-25 the most distant and early (13 billion years old) rotating disc galaxy ever discovered. Courtesy ESO.
Surprisingly, the ALMA data also hinted at more developed features similar to those of the Milky Way. It looks like there’s a central elongated bar, and even spiral arms in REBELS0-25. “Seeing a galaxy with such similarities to our own Milky Way, that is strongly rotation-dominated, challenges our understanding of how quickly galaxies in the early Universe evolve into the orderly galaxies of today’s cosmos,” said Lucie Rowland, a doctoral student at Leiden University who led the research into REBELS-25. “Finding further evidence of more evolved structures would be an exciting discovery, as it would be the most distant galaxy with such structures observed to date.”
What Does This Mean for Galaxy Evolution?
As astronomers discover more of these well-evolved galaxies in the early Universe, they’ll have to adjust the working model of galactic birth and evolution. In that model, the baby galaxies are clumps of stars and gas that come together in collisions and cannibalism to form larger galaxies. It’s typically considered a messy and turbulent time in cosmic history. Infant galaxies collided and grew. They combined their stars and gases to make larger structures. Over time they begin to rotate, which also influences the formation of structures inside the galaxy. Further collisions add more mass to the galaxy, and they also spur bursts of star formation. All of this takes billions of years to accomplish. Or so astronomers always thought.
REBELS-25 and other early spirals challenge that general model. For one thing, REBELS-25 looks like a galaxy that’s evolving at an accelerated pace. Compared to the Milky Way’s ponderous billions of years of evolution, REBELS-25 is going at warp speed. That implies something is pushing that acceleration. T he big thing now will be to explain its advanced evolution at a very young age.
The REBELS program should help astronomers understand more about the processes at work only a few hundred million years after the Big Bang. That survey will supply large enough amounts of data about high-mass galaxies in the early Universe. Those samples should allow astronomers to do targeted studies of more galaxies using both ALMA and JWST. Both observatories are powerful enough to give detailed looks at individual galaxies in those very early epochs of cosmic history.
Cosmology has had several ground-breaking discoveries over the last 100+ years since Einstein developed his theory of relativity. Two of the most prominent were the discovery of the Cosmic Microwave Background (CMB) in 1968 and the confirmation of gravitational waves in 2015. Each utilized different tools, but both lent credence to the Big Bang Theory, which relates to the universe’s formation. However, we still don’t understand a vital part of that formation, and a new review paper by Rishav Roshan and Graham White at the University of Southampton suggests that we might be able to make some headway on our one-second “gap” in knowledge by using our newfound understanding of gravitational waves.
Illustration of the asteroid Bennu. Credit: NASA Jet Propulsion Laboratory
There are four fundamental forces in the Universe. These forces govern all the ways matter can interact, from the sound of an infant’s laugh to the clustering of galaxies a billion light-years away. At least that’s what we’ve thought until recently. Things such as dark matter and dark energy, as well as a few odd interactions in particle physics, have led some researchers to propose a fifth fundamental force. Depending on the model you consider, this new force could explain dark matter and cosmic expansion, or it could interact with elemental particles we haven’t yet detected. There are lots of theories about this hypothetical force. What there isn’t a lot of is evidence. So a new study is looking for evidence in the orbits of asteroids.
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.
