Showing all posts about science
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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Could these extraterrestrials build and pilot flying saucers?
7 February 2025
Kurzgesagt speculates on what extraterrestrial life might look like on planets elsewhere in the galaxy. But this may not be quite what we were expecting…
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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
Shoot for the stars: Tim Teege wants to run a marathon on the Moon
20 December 2024
Hamburg, Germany, based web developer and long distance triathlete, Tim Teege is super keen to run a marathon the Moon. So much so, he wants you to ask any space agency worker type acquaintances you may have, to help him achieve his goal. Ask, and you shall receive, and the like.
Not to put a dampener on Teege’s aspirations, I wonder if he’s read Rhett Allain’s Wired article on the subject:
You can’t go out and jog around the Sea of Tranquility—you’d just start bouncing and floating.
But, as they say, where there’s a will, maybe there’s a way. The laws of physics notwithstanding. Yet here, at the quarter way point of the twenty-first century, the act of somehow being able to run on the Moon, should really be Teege’s only significant challenge.
Getting to the Moon — in this post 2001: A Space Odyssey world — should be as easy as boarding what ought to be regular commercial flights to Earth’s satellite.
The journey might cost a pretty penny, but that’s what crowdfunding is for. Instead, however, in what’s almost 2025, about all we have in terms of reaching the Moon, is NASA’s troubled Artemis program, which seems like a re-run of Apollo, yet appears not to be going anywhere fast.
With 2025 essentially only days away now, I shouldn’t be so indifferent. Big shoot for the stars ambitions and goals are what we need right now. Especially for this particular new year.
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2001: A Space Odyssey, physics, science, sport
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, Pluto, 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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astronomy, science, technology
Gravitational waves may reveal presence of warp drive starships
13 September 2024
Gravitational waves have been helping scientists and astronomers answer some of the big questions of the universe. But gravitational waves may be able to do something else: detect the presence of vessels with Star Trek like warp drive engines, as they move through the cosmos.
One problem with the warp drive space-time is that it doesn’t naturally give gravitational waves unless it starts or stops. Our idea was to study what would happen when a warp drive stopped, particularly in the case of something going wrong. Suppose the warp drive containment field collapsed (a staple storyline in sci-fi); presumably there would be an explosive release of both the exotic matter and gravitational waves. This is something we can, and did, simulate using numerical relativity.
I imagine a cloaking device wouldn’t be much help, if a vessel was trying to move about unnoticed. The gravitational waves generated by the ship’s warp drive would pretty much render it visible.
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