The universe is a vast icebox punctuated by far-flung islands of unbearable heat. Places that could be considered comfortable — neither hot nor cold — are so rare as to be essentially nonexistent. Of course, we happily live on one such planet, the only example of true moderation in the entire known universe. Not so long ago, space itself was thought to register absolute zero, the temperature at which all atomic jiggling terminates, except for some quantum effects. Because heat is simply the movement of atoms, the coldest anything can be is when all such motion has stopped. This happens at –459.67° Fahrenheit (–273.15° Celsius), or 0 kelvin, by definition.
Something strange may be lurking in the outer solar system. The odd orbits of distant space rocks suggest there’s a giant, elusive world dubbed Planet Nine waiting out there to be discovered. But now, in a new research paper, a team of scientists suggest something far stranger may be influencing the orbits of these distant worlds. These astronomers say our solar system may be home to one of the earliest black holes in the universe: a primordial black hole.The Planet Nine hypothesisOver the past few years, astronomers have uncovered about a dozen objects in the distant solar system that defy expectations. In addition to a few other odd attributes, this special subset of icy objects orbiting past Neptune, dubbed Trans-Neptunian Objects, or TNOs, all make their closest approaches to the Sun at about the same spot in space.
Astronomers have all but confirmed the universe has at least one galaxy that's woefully deficient in dark matter. The new finding not only indicates that galaxies really can exist without dark matter, but also raises fundamental questions about how such oddball galaxies form in the first place.The research, posted October 16 on the preprint site arXiv, used Hubble's keen eye to take new, deep images of the ghostly galaxy NGC 1052-DF4 (or DF4 for short). Equipped with fresh observations, the researchers identified the bizarre galaxy's brightest red giant stars (called the Tip of the Red Giant Branch, or TRGB). Because TRGB stars all shine with the same true brightness when viewed in infrared, the only thing that should affect how bright they appear is their distance.So, by identifying the galaxy's TRGB and using that to determine DF4's distance, the new data essentially confirms the galaxy is located some 61 million light-years away. And according to the researchers, this essentially debunks other studies that claim DF4 is much closer and therefore contains a normal amount of dark matter.
In November 2010, astronomers using NASA’s Fermi Gamma-ray Space Telescope announced an astonishing discovery. Emanating from the center of our Milky Way Galaxy are two bubbles made solely of powerful gamma rays. This would have been strange enough if the bubbles, expanding at 2.2 million mph (3.5 million km/h), were concentric — a bubble within a bubble — with both centered at the galaxy’s core. But no, the two enormous spheres each hover in seemingly empty space above and below the black hole in the Milky Way’s nucleus. They are tangent to each other, touching at the galactic center to form a squat hourglass shape. The entire structure looks like the number 8 or a sideways infinity symbol. Gamma rays are the bad boys of the electromagnetic spectrum — the highest-energy photons in the universe. To review high school physics, a photon’s energy is a function of its waves’ lengths. Radiation whose waves are a mile apart (radio waves) are weak and benign; visible light has microscopically close-together waves; X-rays, and especially gamma rays, are crammed together with the maximum number of wave crests passing a given point per second.
What's the difference between dark matter and dark energy?Our universe is dominated by mysterious and invisible forms of matter and energy that have yet to be fully (or even adequately) understood.By Eric Betz | Published: Tuesday, March 3, 2020Most of our universe is hidden in plain sight. Though we can’t see or touch it, most astronomers say the majority of the cosmos consists of dark matter and dark energy. But what is this mysterious, invisible stuff that surrounds us? And what’s the difference between dark energy and dark matter? In short, dark matter slows down the expansion of the universe, while dark energy speeds it up.Dark matter works like an attractive force — a kind of cosmic cement that holds our universe together. This is because dark matter does interact with gravity, but it doesn’t reflect, absorb, or emit light. Meanwhile, dark energy is a repulsive force — a sort of anti-gravity — that drives the universe’s ever-accelerating expansion.Dark energy is the far more dominant force of the two, accounting for roughly 68 percent of the universe’s total mass and energy. Dark matter makes up 27 percent. And the rest — a measly 5 percent — is all the regular matter we see and interact with every day.
Meet the stars next doorThe Sun’s neighbors hide secrets that could help astronomers learn more about our place in the galaxy.Most of the space in the Milky Way Galaxy can be pretty lonely — a dull, dark void. But our own neighborhood stands out as among the more intriguing places in the universe. Recently, with new telescopic technologies, astronomers have made big strides toward finding all our stellar neighbors. Knowing the stellar cast, they can then project this information into the galaxy at large to help us learn how stars, and even planets, are born and live out their lives. As a result of these studies, astronomers are now learning how our own Sun fits into the overall picture.
What lies beneath Triton's iceNeptune’s moon Triton shows tantalizing evidence of water beneath its jumbled crust, making it a high-priority target in the search for life.When VOYAGER 2 flew by neptune and its largest satellite, Triton, in 1989, it revealed a moon with never-before-seen terrain and plumes spurting from the surface. At the time, scientists attributed the plumes to heating from the Sun. But recent advances in understanding ocean worlds such as Jupiter’s moon Europa and Saturn’s moon Enceladus have raised the possibility that Triton’s plumes may indicate it, too, harbors an ocean under its icy crust — a place where life may have managed to evolve.
Dark matter’s shadowy effect on EarthEarth’s periodic passage through the galaxy’s disk could initiate a series of events that ultimately lead to geological cataclysms and mass extinctions.Do geologists dream of a final theory? Most people would say that plate tectonics already serves as geology’s overarching idea. The discovery of plate tectonics 50 years ago was one of the great scientific achievements of the 20th century, but is the theory complete? I think not. Plate tectonics describes Earth’s present geology in terms of the geometry and interactions of its surface plates. Geologists can extrapolate plate motions both back in time and into the future, but they cannot yet derive the behavior and history of plate tectonics from first principles.Although scientists can interpret the history through the lens of what they see today, an important question remains: Why did geologic events — such as hot-spot volcanism, the breakup of continents, fluctuations in seafloor spreading, tectonic episodes, and sea-level oscillations — occur exactly when and where they did? Are they random, or do they follow some sort of a pattern in time or space?A complete theory of Earth should explain geologic activity in the spatial domain, as plate tectonics does quite well for the present (once you incorporate hot spots), but also in the time and frequency domains. Recent findings suggest to me that geology may be on the threshold of a new theory that seeks to explain Earth’s geologic activity in time and space in the context of its astronomical surroundings.
Everything around us is spinning: particles, planets, stars, galaxies. Why not the universe?Cornel Halmaghi, Maple Ridge, British Columbia
The ultimate in social distancing: NASA’s Gemini 7 missionThe flight of Gemini 7 required two astronauts be crammed into a tiny capsule and blasted into orbit. And there they stayed — physically disconnected from the rest of humanity — for nearly 14 full days.
Could alien life be hiding in the clouds of Venus?Though the surface of Venus is a hellish landscape, a new study suggests that microbial life may be able to survive in — and change — the venusian atmosphere.