Showing all posts tagged: astronomy
Does the universe reside within a black hole?
17 March 2025
Good morning, welcome to the new week, and mind-blown Monday. Today we’re discussing life, the universe, the rotation of galaxies, black holes, and everything.
Data collected by the James Webb Space Telescope (JWST) has concluded about two-thirds of galaxies in the universe rotate in one direction, while the remaining third rotate the opposite way. In a supposedly normal course of events, the balance would be more even. Apparently.
But there is any such thing as normal in the cosmos? You know what they say. Truth is stranger than fiction. The universe is not only stranger than we can imagine, it is stranger than we can imagine. Two-thirds of galaxies might spin in one direction, because, you know, just because.
But there’s no just because in this universe. The imbalance in the rotational direction of the galaxies suggests to some astronomers that the universe was born inside a black hole. Since the black hole hosting our universe rotates in one direction, it follows that the majority of galaxies will spin in the same direction. Nikodem Poplawski, a theoretical physicist at the University of New Haven, describes this as the “simplest explanation” of the phenomenon:
“I think that the simplest explanation of the rotating universe is the universe was born in a rotating black hole. Spacetime torsion provides the most natural mechanism that avoids a singularity in a black hole and instead creates a new, closed universe,” Poplawski continued. “A preferred axis in our universe, inherited by the axis of rotation of its parent black hole, might have influenced the rotation dynamics of galaxies, creating the observed clockwise-counterclockwise asymmetry.”
I wonder how far up and down the “levels” of universes residing inside black holes goes then? If our universe is indeed located within a black hole, it follows that other universes must reside within the plentiful black holes that populate our universe. And inside those universes will be yet more black holes, that will be home to further universes. And so on.
But where does our black hole universe sit in such a hierarchy? Near the top? In the middle somewhere. Or near the bottom? If such a thing exists, as there may be no limit to how how far down the progression can go. The same applies going up the other way of course, in theory.
It’s mind blowing stuff for sure. If, that is, you accept this two-thirds versus one-thirds split of galaxy rotation represents a significant imbalance in the first place. There might still be room for just because here. After all, weird things just happen in this wondrous universe of ours.
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No planet has two hundred and seventy plus moons, not even Saturn
15 March 2025
Saturn’s moon count leapt a few days ago, after the International Astronomical Union (IAU) decided to classify an additional one-hundred-and-twenty-eight objects orbiting the ringed planet, as moons. It must be quite the feat of achievement for Saturn to boast it has the most number of satellites, by far, of any other planet in the solar system.
These new moons now mean Saturn is possessed of two-hundred-and-seventy-four satellites. But let’s be serious here. No planet has that many moons, real moons. All of Saturn’s new “moons” are just tiny rocks. They count as moons though, because they have a “proven orbit” around Saturn:
Most of the moons are irregular and tiny, just a few miles across. By comparison, our moon has a diameter of 2,159 miles (3,475 kilometers). But they do have proven orbits around Saturn, which is a key element of official moon candidacy.
Former planet Pluto has a proven orbit around the Sun, yet it is now considered a dwarf planet. This because it no longer meets the IAU’s definition of a planet. We can have different types of planets, it seems, but a moon is always a moon, even it is pet rock size.
But if planetary bodies need to fulfil a certain criteria to be deemed a (real) planet, then a tighter classification of what constitutes a moon, a real moon, is long overdue. If we use our moon, the Moon, as a benchmark, then perhaps Saturn has half a dozen or so “real” moons. The rest would be, as I wrote of Mars’ so-called moons in 2014, merely captured objects.
ETA: on the subject of Saturn, the planet’s fabulous rings will seem to disappear later this month, as far as observers on Earth are concerned. This is because the rings will be edge-on to us, a phenomenon called ring plane crossing, something that happens about every fifteen years.
The rings will become become visible again later in the year though. Who knows, without the rings to distract astronomers on Earth, maybe another batch of moons will be found orbiting Saturn.
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Sending people to Mars will be challenging, for all the wrong reasons
25 February 2025
Maciej Cegłowski’s in depth (deep dive) articles on an array of topics are always worthy reading, even if I’m not always able to consume his pieces in one go. In his latest long form column, he takes on the prospect of sending an Apollo-like flight to Mars, complete with a human crew on board. But going to Mars is not even remotely like a jaunt to the Moon:
A trip to Mars will be commital in a way that has no precedent in human space flight. The moon landings were designed so that any moment the crew could hit the red button and return expeditiously to Earth; engineers spent the brief windows of time when an abort was infeasible chain smoking and chewing on their slide rules.
But within a few days of launch, a Mars-bound crew will have committed to spending years in space with no hope of resupply or rescue. If something goes wrong, the only alternative to completing the mission will be to divert into a long, looping orbit that gets the spacecraft home about two years after departure.
Sending people to Mars is not beyond the realm of possibility, but it will be difficult, incredibly difficult.
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A supermassive black hole is set to collide with the Milky Way
21 February 2025
It’s true: a supermassive black hole is on a collision course with our galaxy. But the happening is at least two billion years away.
And even then it may not be a black hole, but rather a “massive invisible object” thought to lurk within the Large Magellanic Cloud (LMC), a smaller galaxy that presently orbits the Milky Way, but which is slowly falling towards us. Once the LMC collides — though merge is probably a more apt word — with the Milky Way, the black hole, or whatever the invisible body that the LMC hosts, will make a bee-line for Sagittarius A*, the supermassive black hole at the centre of our galaxy.
When those two objects eventually collide — an event that will unfold at a likewise cosmologically glacial pace — the result will be the formation of an even more monstrous black hole.
While the black hole merger process may be drawn out, assuming a black hole indeed resides inside the LMC, it will no doubt be a bumpy ride for whatever interstellar objects lie in the path of the two, as they fuse together. Perhaps the solar system will find itself in harm’s way here. The only consolation there is it’s something we won’t be around to see.
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Gravastars and black holes, a weird cosmic double act
2 January 2025
The concept of gravastars (or gravitational vacuum stars) is a fascinating alternative to the idea of black holes, although if their presence were ever proved, they would not rule out the existence of black holes. Proposed by Pawel O. Mazur and Emil Mottola some twenty years ago, these objects are consistent with Albert Einstein’s general theory of relativity.
Gravastars, like black holes, form in the aftermath of some supernova explosions. They are relatively small, their size might be similar to London, capital of the United Kingdom.
In terms of appearance they are black, and a little like balloons, having an extremely thin shell, consisting of matter scientists do not yet understand. Their interior is filled with a vacuum, or dark energy, bustling to break out, but unable to do so. Gravastars sound like an incredible phenomena, but in a universe some think is devoid of dark energy, I wonder if they could actually be present.
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Albert Einstein, astronomy, physics, science
Time, not dark energy, may be causing the universe to expand
27 December 2024
Dark energy does not exist, and the universe, while continuing to expand, is not doing so in a uniform fashion. In other words, the cosmos may look more like a potato, rather than a sphere. This according to recent research by astronomers and scientists at the University of Canterbury (UC), based in Christchurch, New Zealand.
As if that’s not startling enough, things become truly mind boggling when we look at the nature of time in a universe that may be devoid of dark energy. Time, you see, is moving at different speeds, depending on the location. Within our galaxy, the Milky Way, a clock ticks more slowly than one that might be situated elsewhere in an empty region of the universe, say the mid-point between our galaxy and the Andromeda galaxy, which is two and a half million light years distant.
The model suggests that a clock in the Milky Way would be about 35 percent slower than the same one at an average position in large cosmic voids, meaning billions more years would have passed in voids. This would in turn allow more expansion of space, making it seem like the expansion is getting faster when such vast empty voids grow to dominate the universe.
Because there is more gravity inside a galaxy than outside, clocks will be slower. This is a concept called gravitational time dilation, which Albert Einstein predicted when he published the theories of special relativity and general relativity, early in the twentieth century. Differences in clock speeds may not be surprising then, but the UC research illustrates just how stark these variations might be.
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Albert Einstein, astronomy, physics, science
These are end days for the Voyager space probes
4 December 2024
It almost seems inconceivable that, one year soon, deep space probes Voyager 1 and 2, will cease to function. At some point their on-board power reserves will be completely drained, rendering the vessels unable to collect data, and send it to mission controllers on Earth. We know their batteries will go flat sooner or later, and what equipment that hasn’t yet failed, will eventually. But by the time that happens, they may have been operational for fifty-years.
Both probes have experienced numerous faults of some sort, which mission controllers have mostly been able to rectify. Despite them being almost a light-day distant. Boosting their supply of power, being able to somehow recharge the batteries though, is unfortunately not a solution that can be effected. Various on-board systems can be shut down, but that only acts to conserve power, not replenish it. It’ll be a strange day, the day we learn we’ll no longer hear from either vessel.
Still, the New Horizons probe, which flew passed Pluto in 2015, is still operating as far as I know, so maybe we’ll continue to hear from at least one of our deep space emissaries, after the lights go off on the Voyager probes.
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astronomy, science, technology
The Wow! signal, sun-like stars, and an abundance of hydrogen
28 November 2024
Did an extra-terrestrial intelligence attempt to message us in the distant past? Or did an Earth based radio telescope, nicknamed Big Ear, inadvertently eavesdrop in on a snippet of a conversation between two other alien civilisations? These are among some of the many explanations advanced to understand the so-called Wow! signal, a suspected narrowband radio transmission detected by Jerry R. Ehman, an astronomer working on an early inception of the SETI Project, almost fifty years ago.
Despite being a narrowband signal, which might indicate the presence of intelligent life somewhere, there could any number of explanations to account for the supposed transmission. Some sort of natural phenomena, one we do not yet understand, may well be the cause.
But that hasn’t stopped anyone from daring to live in hope, even though no identical, or repeat, signals have seemingly been observed since. Alberto Caballero, a Spanish astronomer, using data collected by the Gaia space observatory, analysed the area of the galaxy where the Wow! originated. He found about sixty stars, similar to our star, the Sun, in the region. For people searching for signs of extra-terrestrial intelligence, sun-like stars are a common starting point.
If intelligent life emerged here on Earth, a planet orbiting a G-Type main-sequence star, the Sun, then just maybe the same could happen on an Earth-like plant, around another star similar to the Sun, somewhere else. In his research, Caballero identified a candidate star of particular interest to him, with the catchy name of 2MASS 19281982-2640123, located some eighteen-hundred light years from us. Take a second to consider that. Travelling at the speed of light, the would-be transmission was sent during the height of the Roman Empire.
But, in a galaxy quite possibly devoid of intelligent life, with the exception of humanity — if current indications are anything to go by — how incredible would it be that a narrowband-radio-signal-transmitting-alien-civilisation turned out to be — on a cosmological scale — a mere hop, skip, and jump, away?
2MASS 19281982-2640123, and any planets the star may host however, was eliminated after a radio telescope scan last year. Observations, conducted by two radio telescopes, failed to detect any technosignatures, which would point to the presence of a technological civilisation. But not all is lost, there are another sixty or so possible stars Caballero, and other astronomers, could look at next.
Then again, for those hoping the Wow! was sent by someone, far, far away, perhaps all is lost. Fred Watson, an Australian astronomer, writing for Australian Geographic, says some new research conducted by American and Colombian scientists, has discovered numerous instances of Wow! signal like phenomena throughout space:
In research recently announced, a team from the USA and Colombia have used data from a since decommissioned radio telescope at Arecibo in Puerto Rico to look for similar phenomena to the Wow! signal. And they’ve found them, differing only from the original in their lower intensity. All these signals carry the wavelength signature of cold hydrogen, the most abundant element in the universe. It’s commonly expected to be the preferred wavelength for communication by intelligent extraterrestrials — hence the Big Ear’s tuning to this wavelength in the original SETI experiment.
This is not the first time hydrogen has been theorised to be somehow responsible for the Wow!. In 2017, a group of researchers at the Center of Planetary Science said they had determined a hydrogen cloud, accompanying a comet, that was in the region of the galaxy where the Wow! was detected, was the cause. Other scientists, however, were not comfortable with the idea.
It remains to be seen what other astronomers make of the conclusion of the American and Colombian scientists. It seems to me though, the remaining, unchecked sun-like stars, and any surrounding planets, Caballero suspects may be the origin of the Wow!, should be looked more closely anyway. Because one never knows what lurks behind all that hydrogen.
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Unfortunately, colonising Mars is not a great idea
23 September 2024
There’s the challenge. There’s the adventure, the pioneering spirit, of setting off to another planet. Not everything is, or should be, easy. But are those really the right reasons for wishing to establish a human colony on the fourth rock from the Sun, Mars?
Mars does not have a magnetosphere. Any discussion of humans ever settling the red planet can stop right there, but of course it never does. Do you have a low-cost plan for, uh, creating a gigantic active dynamo at Mars’s dead core? No? Well. It’s fine. I’m sure you have some other workable, sustainable plan for shielding live Mars inhabitants from deadly solar and cosmic radiation, forever. No? Huh. Well then let’s discuss something else equally realistic, like your plan to build a condo complex in Middle Earth.
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Another day, another problem with Voyager 1, solved
20 September 2024
Data the nearly fifty-year old deep space probe was returning to Earth earlier this year, was getting all scrambled up. But dutiful mission controllers sorted that out. This despite Voyager 1 being so far away that it’d take a day to reach, assuming we had a vessel that could travel at the speed of light.
More recently, Voyager 1 has been having have trouble using correcting thrusters that keep the probe’s antenna pointed at Earth. Fuel pipes to the aging thrusters have begun to clog up, rendering them inoperative. Mission controllers, at the Jet Propulsion Laboratory, in California, however have been able to re-activate another set of thrusters — unused in decades — and effect a fix.
As a result of its exceptionally long-lived mission, Voyager 1 experiences issues as its parts age in the frigid outer reaches beyond our solar system. When an issue crops up, engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, have to get creative while still being careful of how the spacecraft will react to any changes.
If you want a tricky problem solved, ask a mission controller from one of the automated space missions to help. And of course Apollo 13.
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