Buzz
Galactic anomalies have the power to humble both seasoned researchers and casual skywatchers by defying expectations of the cosmos. Fortunately, these phenomena are eager to reveal their secrets, if we only take the time to understand them.
10. Triangulum II
The nearby Triangulum II galaxy has left Caltech researchers stunned due to its incredibly fast stars. This small galactic neighbor contains roughly 1,000 stars, a mere fraction compared to the 100 billion stars in our own galaxy. Yet, Triangulum II hides a vast amount of unseen mass.
Using the powerful Keck telescopes atop Mauna Kea, astronomers observed six of these stars speeding far beyond what was anticipated, given the galaxy's relatively modest size. This unexpected star speed allowed researchers to assess Triangulum II’s gravitational influence and overall mass.
They discovered the most concentrated dark matter of any galaxy studied to date. However, French researchers from the University of Strasbourg argue that the gravitational pull from neighboring galaxies is what’s causing the stars to move erratically.
If the galaxy is indeed packed with dark matter, it presents a prime opportunity to directly observe this elusive substance, which makes up 24 percent of the universe’s mass. A peculiar trait of dark matter particles—if they exist—is that they appear to annihilate each other upon contact, emitting a burst of gamma rays. Since Triangulum II is a dead galaxy, these signals should be clear and free from interference by other cosmic energy sources found in more active areas.
9. The Enigmatic Galactic Ring
Astronomers from the US and Hungary recently made an astounding discovery—a structure so enormous it defies belief: a galactic ring stretching five billion light-years across. This incredible formation spans an area of sky 70 times greater than the width of the full Moon.
The size of the ring is suggested by the proximity of seven detected gamma-ray bursts (GRBs), the most intense events known in the universe. GRBs occur when massive stars undergo hypernova explosions and collapse into black holes.
Given that the seven bursts were at such comparable distances, astronomers inferred the presence of an enormous structure made up of connected galactic hot spots. While it could just be a coincidence, researchers argue that the odds of this happening are a remarkable 20,000 to 1.
The ring challenges our cosmological models, which prohibit the formation of such vast structures and limit their size to around 1.2 billion light-years. These models predict a universe with a relatively uniform distribution—an idea supported by early images taken shortly after the big bang launched the universe into existence.
If the ring does exist, why is it so staggeringly large? The answer remains a mystery, though dark matter could play a role in holding everything together.
8. Tayna The Firstborn
By combining the capabilities of the Hubble and Spitzer space telescopes, astronomers have observed the faintest galaxy ever. They looked back in time to just 400 million years after the big bang to uncover this new type of ultrafaint galaxy, previously undetected by astronomers.
The galaxy is named Tayna, which translates to 'firstborn' in the Aymara language, native to South America's Andes and Altiplano. While it may appear to be the most isolated galaxy, it is actually one of 22 similar sibling galaxies situated near the observable edge of the universe.
To observe Tayna, positioned far across the cosmos, required the collaboration of two of our most advanced space telescopes, along with a significant assist from the galaxy cluster MACS J0416.1-2403, located four billion light-years away. With its mass of one quadrillion Suns, the cluster acted as a gravitational lens, magnifying the light passing through it and allowing us to catch a glimpse of Tayna in all its red, pixelated splendor.
The James Webb Space Telescope, scheduled for a 2018 launch, will provide a far clearer view of Tayna and its nascent counterparts, offering an in-depth look at the earliest galaxies. Although we can't yet see Tayna in its mature form, its early stages suggest a galaxy with a rapid rate of star formation, likely evolving into a well-formed galaxy over time.
7. The Breast-Feeding Galaxy
Astronomers are still uncertain about the origins of galaxies. Do gases like hydrogen spiral toward massive dark matter clumps, forming gravitational hubs for galaxy birth? Or do galaxies receive nourishment from a gaseous intergalactic pipeline, akin to an ethereal mother bird feeding its young? The first scenario is too slow to align with observed data, and the second has yet to be observed.
Up until now, Caltech researchers have utilized their Cosmic Web Imager to spot a protogalactic disk (a baby galaxy) 10 billion light-years away, which is being nourished by a massive strand of hydrogen-rich gas. This strand is part of a much larger, interconnected cosmic web of untapped stellar resources.
Thanks to the fortunate positioning of two quasars, the active strand appeared much brighter than the surrounding network, standing out like a fiery thumb. The strand is flowing into a large disk, which brilliantly reflects the light from its quasar neighbors.
6. The Large Magellanic Bully
The Large Magellanic Cloud (LMC) and its underfed companion, the Small Magellanic Cloud (SMC), are our closest galactic neighbors, located 160,000 and 200,000 light-years away, respectively. As the largest of the dwarf galaxies orbiting the Milky Way, they are visible to the naked eye in the southern hemisphere’s night sky.
However, strange events are unfolding in the LMC. In the eerily named Tarantula Nebula, astronomers have discovered a thriving star nursery—so prolific that if it were located more than 1,000 light-years away, its activity would cast shadows on Earth.
Additionally, of the 5,900 giant and supergiant stars studied in the LMC, 5 percent seem to have traveled from distant regions. These stars follow unusual orbits and are composed of the wrong elements, lacking heavier elements like iron and calcium, as if they’ve been deprived of necessary nutrients.
Astronomers have realized that the LMC has been stealing stars from its smaller sibling. Chemically, the stars of the SMC resemble those now found in the LMC. The term “cosmic highway robber” also explains the extraordinary fertility of the Tarantula Nebula. The LMC is also siphoning gas, drawing it in so quickly that it “ignites” upon contact with the larger galaxy’s leftover reserves.
5. Hercules A
At the heart of Hercules A (also known as 3C 348) lies a monstrous black hole with a mass of 2.5 billion Suns! This beast is 1,000 times the mass of the Milky Way’s own black hole and unleashes two immense plasma jets that obscure the much smaller galaxy it resides in.
The jets stretch an astonishing 1.5 million light-years into space, dwarfing many other galaxies, including the Milky Way, which is roughly 15 times less formidable. The energy involved is staggering: The black hole at the center produces one billion times more power than our Sun at radio wavelengths.
This makes Hercules A one of the brightest radio sources ever recorded. The pinkish-red beam is a mix of plasma, subatomic particles, and magnetic fields moving at relativistic speeds (close to the speed of light). The jagged outer edges hint at numerous past eruptions.
Unfortunately, this phenomenon is invisible to the naked eye. The radio lobes are only visible in composite images, which are created by combining visible light data from Hubble’s Wide Field Camera 3 and radio observations from the Karl G. Jansky Very Large Array.
4. The Milky Way’s Ancient White Dwarfs
Our galaxy is no youngster. In fact, it’s nearly as old as the universe itself. Deep within the Milky Way’s central bulge, astronomers have found a group of 70 white dwarfs, which are dense remnants of stars, each with the mass of the Sun compacted into an Earth-sized body.
These ancient dwarfs were uncovered in a sweeping view of the Milky Way’s densely packed core, located around 25,000 light-years from Earth, in a region that NASA has described as a “cosmic archaeological dig.” Amid the multitude of stars, researchers identified these 12-billion-year-old embers that once burned brightly and met relatively gentle ends.
Though they are now merely relics, these stars provide valuable insight into the history of our galaxy. It’s believed that these white dwarfs helped to seed the Milky Way—a process that took less than two billion years. Their example set the stage for the formation of hundreds of billions of stars, ultimately shaping the Milky Way into the spiral galaxy that spans 100,000 light-years.
3. EGS8p7 Shouldn’t Be Visible
At over 13.2 billion years old, galaxy EGS8p7 is so ancient that it defies expectations of visibility. After the big bang, the universe was a hot, chaotic mix of protons and electrons. As it cooled, these particles merged into neutral hydrogen.
In this scenario, neutral is problematic: it’s opaque and prevents us from observing the early universe. Luckily, as galaxies and other energetic structures began to form, they reionized the gas, clearing the fog and allowing light to illuminate the universe once more.
Despite the fact that this event happened around one billion years ago, EGS8p7 should be too far away to observe. Yet, astronomers managed to detect its Lyman-alpha line, which acts like a unique galactic barcode.
This line forms when youthful, energetic stars emit UV light that interacts with the surrounding gas, leaving behind a thermal signature. The Keck Observatory’s MOSFIRE spectrometer was able to pick up this signature, even though EGS8p7’s line should have been concealed by the early universe’s hydrogen fog.
Astronomers are still puzzled by how EGS8p7 managed to pull off this trick. Perhaps it was so massive and its stars so powerful that it reionized a vast region of the universe much earlier than most galaxies did.
2. Tiny Galaxy With Huge Black Hole
M60-UCD1, a tiny galaxy, could reshape our understanding of black holes and dwarf galaxies. Measuring just 300 light-years across—0.2% of the Milky Way's size—it holds a black hole weighing 21 million Suns. By contrast, the much larger Milky Way's black hole has a mass of only four million Suns.
Previously, it was believed that a galaxy's size and the mass of its black hole went hand in hand. This new discovery upends that theory, indicating that black holes may be far more widespread than we once imagined.
This unexpected phenomenon occurred because M60-UCD1 wasn’t always so small. Astronomers from the University of Utah suggest it once had a massive 10 billion stars. However, it drifted too close to a more powerful neighbor, which stole most of its stars.
After retaining roughly 140 million stars, M60-UCD1 now holds the title of the smallest galaxy with a supermassive black hole. This discovery also raises a fascinating question: Do dwarf galaxies form from a slow collection of stars, or are they simply remnants of larger cosmic structures?
One advantage to residing in a star-deprived galaxy is the breathtaking night sky. With more than 100 million stars packed tightly together, the view is a radiant flood of light that is nothing short of spectacular.
1. The Incredibly Bright Galaxy
NASA’s WISE (Wide-field Infrared Survey Explorer) space telescope has discovered the most luminous galaxy ever observed, shining with the combined brilliance of over 300 trillion Suns. The light from galaxy WISE J224607.57-052635.0 traveled 12.5 billion years to reach us, offering a glimpse of the universe when it was only one-tenth its current age.
This galaxy is so intensely bright that even an artist’s depiction can be almost blinding. However, the incredible luminosity isn’t from starlight, but from a black hole so massive that it challenges our understanding of physics.
It’s a complete shock that the early universe could contain such a cosmic giant. Black holes have limits on how much they can consume, and there wasn’t enough time for all of this matter to spiral into its center.
This black hole must have formed large from the beginning or somehow circumvented the usual feeding limits multiple times to achieve its current mass. In either case, it indulged in such excess that it’s now spewing out material. This high-energy expulsion slams into the surrounding dust cocoon, creating the galaxy’s radiant glow.
So, that dazzling image is the result of a black hole’s explosive ejecta. But it’s not the only one. Using infrared technology, WISE has uncovered a number of other ultra-bright galaxies whose visible light is hidden by the cosmic dust surrounding them.
+ Andromeda Halo
Andromeda (M31), our nearest substantial neighbor, is surrounded by a massive halo. Twice the size of the Milky Way, this gigantic galaxy already spans 200,000 light-years, and its gaseous halo extends this by an additional one million light-years.
Quasars located far in the distance acted as guides, providing astronomers with valuable help in studying Andromeda. The faint ultraviolet light they emitted, as it reached Hubble, allowed researchers to estimate how much thin, dispersed material must surround Andromeda to create such a visual effect.
Housing half of Andromeda’s gas, the halo acts as a massive stellar reservoir, fueling and regulating star formation. It's also abundant in the heavier elements ejected by Andromeda’s numerous past supernovae, which were thrown to the far reaches of the galaxy.
Unfortunately, the halo is beyond the reach of our human vision. If we could see it, we’d be treated to a spectacular night sky. Andromeda’s halo would stretch across an area 100 times the diameter of the full Moon. Alternatively, you can get a sense of its vastness by holding two basketballs at arm's length, giving you an idea of the immense scale of an object 2.5 million light-years away.
