Showing all posts tagged: astronomy

Black hole stars, a weird cosmic entity and Soundgarden song

18 December 2022

Black hole stars, sometimes called quasi-stars, were a hypothetical star that may have existed in the earliest days of the universe, up to about half a billion years after the Big Bang.

They were larger — far larger — than any star known to be present in the universe today, and were capable of outshining entire galaxies. And, as the name suggests, they were part black hole. We know some stars become black holes at the end of their lives, but for the two to somehow co-exist, star and black hole, without one destroying the other? How can such a thing even happen?

In 1927, British-Indian scientist J. B. S. Haldane, in an essay titled “Possible Worlds” wrote the oft quoted sentence: “now, my own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose.” It was Haldane’s way of saying we’re unlikely to ever make sense of the universe, no matter how much we learn about it. Black hole stars, in their bizarre weirdness, only add to the wonder.

And, as a bonus, American rock/grunge act Soundgarden’s 1994 track, Black Hole Sun, written by the late Chris Cornell, takes on a whole (er, no pun intended) new meaning in this context.

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Could flight of the bird propulsion power deep space travel

11 December 2022

It may be possible to construct deep space vessels capable of (eventually) reaching speeds equal to two percent of the speed of light:

Scientists have proposed a dazzling new mission to travel to the stars that is inspired by the elegant flights of seabirds, such as albatrosses, reports a new study. The interstellar concept mission would harness shifting winds generated by the Sun in order to accelerate a spacecraft to as much as 2 percent the speed of light within two years, allowing it to soar into the vast expanse beyond our solar system.

But two percent the speed of light, a velocity that would take some time to attain anyway, isn’t all that speedy considering the vast distances between celestial objects, such as the Sun, and the nearest star to us, Proxima Centauri.

If we round off the speed of light at 300,000 kilometres (km) per second, two percent of that is six thousand km per second. That’s 360,000 km per minute, and 21,600,000 km per hour. 518,400,000 km per day. If my maths is on spec — not always guaranteed — the journey to Proxima Centauri, some 40,208,000,000,000 km distant, would take 77,561 days, or about 213 years.

On the other hand, if Pluto is an average of 5,300,000,000 km from Earth — sometimes it is closer, sometimes more distant — it would take about ten days to travel there. Assuming such speeds could be attained at relatively close proximity to the Sun, that is. This method of deep space travel seems reasonable for reaching points in and near the solar system, but might be out of the question for interstellar voyages carrying people.

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Alcyoneus a sixteen million light year long radio galaxy

4 December 2022
Spiral galaxy, image by A Owen

Image courtesy of A Owen.

Alcyoneus, a galaxy located some three and a half billion light years from Earth, at over sixteen million light years in length, is — without putting too finer a point on it — staggeringly huge. Our home galaxy, the Milky Way, at a mere one hundred thousand light years long, is positively minuscule in comparison.

But Alcyoneus isn’t a sixteen million light year long container of stars and whatever else fills a galaxy. Alcyoneus is what’s known as a radio galaxy, and the bulk of its length comes from radio lobes, which are a little like jets of radio energy, that fire out from opposite sides, into the surrounding space.

At its starry core Alcyoneus, which is likely an elliptical galaxy (unlike the image of the spiral type galaxy I’ve featured above), may not be all that much larger than the Milky Way. And that’s probably a relief for members of Alcyoneus’ galactic council, who only have to travel several hundred thousand light years to visit their constituents, rather than multiple millions.

If radio galaxies intrigue you though, Universe Guide has put together this explainer.

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The Sun will not go supernova but it may still drive us away

25 November 2022

In five billion years, hopefully long after a, hopefully, still extant humanity have departed the solar system for a new home somewhere among the stars, the Sun will become a red giant star. In this late phase of its life, the Sun will expand in size to engulf all the solar system’s inner planets.

While this part of the Sun’s lifecycle will be relatively short-lived — some estimates suggest a mere one billion years — our home planet will have well and truly been obliterated, by the time the Sun shrinks in size again. Unless of course any of our descendants, who stayed home, succeeded in moving Earth further out into the solar system.

The idea has been mooted previously. Even before the Sun becomes a red giant, its gradually increasing heat output, or luminosity, will, in time, make living on Earth ever more uncomfortable.

Such as undertaking will be quite the feat of astronomical engineering. Being able to move the planet will be an achievement in itself, to say nothing of navigating to a suitable spot elsewhere, clear of the larger outer planets. But what happens when the Sun shrinks and cools off again? Do we try and send Earth sunwards again? Perhaps our efforts would be better served finding a Earth-twin planet to live on, orbiting a younger star. And, while we’re at it, figuring out a way of reaching said location in a reasonable timeframe.

At least it’s not something we need concern ourselves with right this minute though. Likewise, the prospect of the Sun exploding as a supernova. It’s something that cannot happen. But what about another star — one in the approximate proximity of the solar system — going supernova? That could be a whole another story.

That’s the question the people at Kurzgesagt explore this month, in their latest video presentation. Again the prospect of a relatively nearby star exploding is not something that will occur any time soon. At present, IK Pegasi, a binary star some one hundred and fifty four light years away, is the nearest possibility, though by the time it is projected to explode, it will be more like five hundred light years distant.

Still as Kurzgesagt explains, risks remain, and even supernovas occurring at some distance could have an impact, no matter how minor, on Earth.

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Tune into the aftermath of the Big Bang on television

21 November 2022

If you’re still using an aerial (is that still a thing?) instead of cable (is that still a thing?) or internet, to watch TV, and — presumably — still possess an old school (think rabbit ears) TV, you may be able to pickup remnants of the Big Bang, the force of cosmic nature, that brought the universe into being.

Like COBE, WMAP scans the sky over and over again, soaking up the ancient light from the Big Bang known as the cosmic microwave background. Microwaves are a low-energy form of radiation but higher in energy than radio waves. The cosmic microwave background blankets the universe and is responsible for a sizeable amount of static on your television set–well, before the days of cable. Turn your television to an “in between” channel, and part of the static you’ll see is the afterglow of the big bang.

All you’d see is static, some of which may be post Big Bang microwaves bouncing around the cosmos, but it might be more interesting than some of what is broadcast on the terrestrial channels.

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If the International Space Station orbited at 3000 metres

9 November 2022

What if the International Space Station orbited at a height of just three thousand metres? Benjamin Granville decided to find out. The answer to many “what-if” questions are often perfectly implausible, but some sure are worth asking. The scenario makes for quite the ride for those aboard the station…

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DART helping to protect Earth from off planet threats

29 September 2022

It could be argued we’re not doing as much as we could to avert potential catastrophes on the planet. Climate change and global conflict would be two examples. When it comes countering possible threats from outside though, some progress is being made.

The test of an asteroid defence system, whereby a NASA probe was sent to collide with Dimorphos, a celestial object, to effect a change, albeit minor, in its trajectory, is one instance.

NASA did not send this probe to observe this asteroid or even scoop some samples from its surface to bring back to Earth, as other missions have done. The agency dispatched the spacecraft with the explicit hope of crashing it and changing the asteroid’s trajectory. This is a test run, but a future version of this mission could save Earth from a catastrophic impact by deflecting an asteroid on a collision course. A little bit of practice never hurts.

While Dimorphos does not pose a threat to Earth — at least not at the moment — another asteroid such as the one that brought about the demise of the dinosaurs, might in the future.

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Sydney to host the 2025 International Astronautical Congress

26 September 2022

With a number of planets, particularly Jupiter, dominating the eastern night sky of Australia at the moment, what better time to make mention that the 2025 International Astronautical Congress (IAC) will be held in the NSW capital, Sydney.

Founded in 1951, the International Astronautical Federation (IAF) is the world’s leading space advocacy body with around 460 members in 72 countries, including all leading space agencies, companies, research institutions, universities, societies, associations, institutes and museums worldwide. The Federation advances knowledge about space, supporting the development and application of space assets by promoting global cooperation.

The last time Australia hosted an IAC event was in 2017, when the International Astronautical Federation conference took place in Adelaide, South Australia.

On the subject of astronomical matters, check out If the Moon were only one pixel, by American interactive art director and designer Josh Worth. Now we can see why they call it space

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UFO sightings surge in skies above Ukraine recently

16 September 2022

Astronomers in Ukraine have observed an uptick in unidentified flying objects over the country in recent months. While it seem obvious there would be more aerial activity with a war raging in the region, scientists are adamant what they’re seeing in Ukrainian skies are not military vessels.

Ukraine astronomers have reported a slew of UFOs observed in the country’s airspace. They’ve reported their findings in a preprint paper published by Kyiv’s Main Astronomical Observatory Ukraine’s National Academy of Science. Remember, UFOs don’t necessarily mean extraterrestrial spaceships from other planets. Perhaps they are advanced military aircraft from much closer to home, like even from one of Ukraine’s (ahem) neighbors.

All the more curious given recent reports from US Navy pilots who say they’ve seen unidentified flying objects during flight operations. Are unidentified flying objects drawn to areas where military craft are operating?

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Video of a solar eclipse on Mars, Phobos occults the Sun

30 August 2022

Footage of a solar eclipse on Mars, filmed by NASA roving probe Curiosity. Eclipses on Mars are a little different to those we are treated to on Earth though, with the speed of the red planet’s “moontatoes” making the phenomenon more of a blink and you’ll miss it occasion.

Mars’ moons Phobos (“fear” in Ancient Greek) and Deimos (“dread”) circle Mars every 7.65 and 30.35 hours respectively, a relative blink compared to the 27-day orbit of Earth’s moon. They’re also a lot smaller than the Moon, and considerably more lumpy – little moontatoes, rather than the nice round disk we see shining so argently in our night sky.

It makes me think. If Pluto doesn’t make the grade as a “proper” planet, why should the so-called satellites of Mars be regarded as moons? Surely “captured objects” would be a more apt classification.

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Bits of Saturn, a Twitter account posting Cassini probe images

27 August 2022
Saturn, photo by NASA Cassini probe

Speaking of Twitter, while a number of accounts may be automated or bots, they’re not all bad. Bits of Saturn, which posts raw images of the ringed planet, taken by NASA’s Cassini probe, between 2004 and 2017, is one you should follow.

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The sound of the Perseus galaxy cluster black hole

25 August 2022

NASA have again been applying sound, or musical notes, to the data they’ve collected from objects in the universe — a process called sonification — this time a black hole located about two-hundred-and-forty million light years away in the Perseus galaxy cluster.

People have variously likened the droning sound produced by the black hole to wailing ghosts or grumbling, hungry, stomachs. Somehow I think of water draining down a plughole.

The Perseus galaxy cluster is intriguing of itself being, according to Wikipedia, one of the most massive objects in the known universe, containing thousands of galaxies immersed in a vast cloud of multimillion-degree gas. I doubt we’ll be sending our star ships too close to that cluster…

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5000 exoplanets pinpointed and given a sound signature

23 August 2022

Prior to 1992 exoplanets — being planets orbiting stars other than the Sun — were unheard of. While scientists believed they existed, thirty years ago none had been found. Today though exoplanets are the rule rather than the exception with over five thousand such bodies having been identified so far.

And with an estimated one-hundred-thousand-million stars in our galaxy, the Milky Way, it is likely many, many, more exoplanets will come to light. This nifty animation and sonification produced by NASA pinpoints the location of stars hosting exoplanets, while a pitch or chime conveys other information about the planet.

This animation and sonification tracks humanity’s discovery of the planets beyond our solar system over time. Turning NASA data into sounds allows users to hear the pace of discovery, with additional information conveyed by the notes themselves. As each exoplanet is discovered, a circle appears at its position in the sky. The size of the circle indicates the relative size of the planet’s orbit and the color indicates which planet detection method was used to discover it. The music is created by playing a note for each newly discovered world. The pitch of the note indicates the relative orbital period of the planet. Planets that take a longer time to orbit their stars are heard as lower notes, while planets that orbit more quickly are heard as higher notes.

The question now is how many exoplanets are capable of supporting life (as we know it), and is life present on any of these bodies.

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Super clear photos of Jupiter taken by the Juno probe

3 August 2022
Image of Jupiter, via NASA JunoCam

Image courtesy of NASA/Juno spacecraft.

A selection of some of the clearest photos taken so far, of Jupiter, the largest planet in the Solar System, by NASA’s Juno spacecraft. This stunning image dates from 2019. Juno has been photographing the gas giant since 2016, on a mission originally expected to last five years. NASA is hopeful however the probe will remain operational until 2025.

More of Juno’s photos can be seen here.

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Astronomers call for James Webb Space Telescope to be renamed

21 July 2022

While the images being collected by the newly operational James Webb Space Telescope have been stunning, some people are questioning whether the telescope should be named in honour of James Webb. Webb was NASA administrator from 1961 until 1968, and during his tenure he oversaw preparations for the early Apollo Moon flights.

But some astronomers and scientists are calling for NASA to rename the space telescope in light of allegations Webb persecuted LGBTQIA+ people, during, and before, his time as NASA administrator.

The telescope’s name has been criticised by many scientists amid allegations that Webb was linked to persecution of LGBTQ+ people in the 1950s and 1960s. The Lavender Scare witch-hunt resulted in the mass dismissal of gay and lesbian people from the US government service in the mid-20th century.

To date NASA has refused to yield, claiming there is no evidence supporting the allegations against Webb.

In September last year, NASA announced it would not change the telescope’s name. “We have found no evidence at this time that warrants changing the name of the James Webb space telescope,” NASA’s current administrator Bill Nelson said in a statement in September.

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First images from the James Webb Space Telescope

14 July 2022

NASA released the first images captured by the brand new James Webb Space Telescope (JWST), on Tuesday, and they did not disappoint.

The first operational JWST photo is of the SMACS 0723 galaxy cluster, which is a little over five billion light years distant. Incredible isn’t it? The cluster seems far closer. What we’re really seeing here though is a snapshot of the cluster as it appeared five billion years ago.

Check out the red streak, that looks a little like a forward-slash towards the bottom centre. According to Rebecca Allen, an astronomer at Swinburne University of Technology, this was a galaxy with many of its stars still forming. Five billion years later, it might look like our galaxy, the Milky Way, today.

SMACS 0723 galaxy cluster

Image courtesy NASA, ESA, CSA, STScI, Webb ERO.

This picture of the Southern Ring Nebula, also known as Eight-Burst Nebula, and Caldwell 74, depicts the death throes of a binary star. The cloud of dust, hydrogen, and ionised gas, surrounding the binary is about half a light year across.

Southern Ring Nebula

Image courtesy NASA, ESA, CSA, and STScI.

The Carina Nebula, situated some 8500 light years from Earth, is the sort of image we love seeing from deep space telescopes. Brimming with colour, pearly bright stars in the foreground, and intrigue, these nebulae are akin to intricate tapestries.

Carina Nebula

Image courtesy NASA, ESA, CSA, and STScI.

Hands up who’s hanging out for the next batch of JWST images…

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What next after finding the goddamn Higgs boson particle?

14 July 2022

The Large Hadron Collider (LHC) is being fired up again after an extensive upgrade, and expectations are high the revamped particle collider will yield further of the universe’s secrets. Australian journalist Sherryn Groch has written about what scientists hope to learn in the next round of LHC experiments, as part of the Sydney Morning Herald Explainer series of articles.

For many people the LHC is most notable for finally confirming the existence of the elusive Higgs boson, nicknamed the goddamn particle by some scientists, on account of the difficulty they had finding it. The discovery though wasn’t quite the missing piece of the puzzle physicists expected it to be, says Dr Mitesh Patel, a lead researcher at CERN, giving rise to the possibility a fifth force of nature may exist, over and above the presently accepted four.

And then there’s the Higgs boson itself: it’s much lighter than expected. “It doesn’t really make sense on its own,” Patel says. “Everything about it tells us its mass should be much heavier. So, is something keeping it low? That’s what makes us think there’s something else.”

But the plot thickens. Shortly before the LHC was deactivated for upgrade, Patel and his team were struggling to make sense of data they had gleaned from older LHC experiments. What they were seeing didn’t stack up against the tenets of the Standard Model of physics, used to account for the four forces of nature, being electromagnetism, the weak force, the strong force, and gravity, even if the Standard Model does not actually explain gravity.

In the subatomic realm, particles interact and change all the time. And, according to the standard model, those known as beauty quarks should decay as often into muons as they do into electrons. But on the CERN team’s measurements, they became electrons 15 per cent more often than the muons, suggesting something could be tipping the scales.

Scientists are hoping further LHC experiments will also tell them more about dark matter, which coupled with dark energy, makes up ninety-five percent of the universe. But gravity remains the mystery. Standard Model does not account for it, and scientists are puzzled as to why it is far weaker than the other forces of nature. But they have some mind-boggling suggestions as to why:

[Some] speculate whether dark matter is really the effects of matter in another universe – gravity leaking through a multiverse into our own. It sounds like a Marvel film but Patel says “there are decent foundations” for the theory, namely that scientists still don’t understand why gravity is so much weaker than the other three forces of nature. “So people have speculated that maybe gravity behaves differently because it’s spread out in other dimensions in addition to our own”.

It is possible insights into these puzzles may be forthcoming sooner rather than later, once the LHC is up and running again. This I am looking forward to.

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Saturn’s rings and moons silhouette woodcut by Agnes Giberne

12 July 2022
Saturn's rings, moons, illustration by Agnes Giberne

The things you find while trawling through the The Public Domain ReviewAgnes Giberne was a British novelist and science writer, who died aged 93 in 1939. As a writer her output was prolific.

Wikipedia lists one hundred and thirty books published under her name during her lifetime. On top of her writing though, Giberne was also an accomplished artist and illustrator.

The above illustration, titled “Ideal view of Saturn’s rings and satellites from the planet” is a silhouette woodcut from her book, Sun, Moon, and Stars: A Book for Beginners, which was published in 1898.

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2022 astronomy photographer of the year shortlist

7 July 2022

The 2022 astronomy photographer of the year shortlist was unveiled on Tuesday 5 July. The award, organised by the Royal Observatory Greenwich is in its thirteenth year, and the entries, as usual, never fail to amaze. Shortlisted images are on display at London’s National Maritime Museum until Sunday 7 August 2022, with the winners being announced on Thursday 15 September 2022.

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Space bubbles a Dyson sphere like solution to global warming?

15 June 2022

Dyson spheres are hypothetical mega-structures highly advanced planetary civilisations might construct around their host star to harness as much solar energy as possible to power their needs. Seen from a distance, a Dyson sphere would look like a massive shell almost completely encompassing a star.

It’d be like constructing a giant display case for the Sun. Needless to say building a Dyson sphere is no small undertaking, and would require an enormous quantity of resources, technological smarts, plus an unprecedented level of international cooperation. A single superpower could not take on an engineering feat of this scale alone, it’d be a team effort.

Dyson spheres have been in the news relatively recently. Fluctuations in the light of Tabby’s Star, located about 1,470 light-years from Earth, were puzzling astronomers, and the existence of a Dyson sphere was advanced as a possible explanation, though later ruled out.

While Dyson spheres, something late British American mathematician and physicist Freeman Dyson first wrote about in 1960, are unlikely to feature in our future anytime soon, the concept may help us combat global warming.

A team of MIT scientists have devised a solar filter of sorts, they call space bubbles. In short, a small structure made up of numerous of these space bubbles could be used to form a shield, deflecting a small, though sufficient amount of solar radiation away from the Earth.

The MIT scientists propose placing the space bubbles at the Lagrange point between the Earth and the Sun. Put simply, a Legrange point, is an area between two celestial objects, say the Earth and the Sun, where the gravity of both objects balance each other. For example if a satellite were placed at this Legrange point, it would stay put, and wouldn’t fall towards either the Earth or Sun.

Once in place, the space bubbles would act like an eclipsing body, in this case permanently blocking, or more like filtering, a small amount of the Sun’s rays reaching the Earth. While the proportion of solar radiation “blocked” would be minuscule, the MIT team say if just under two percent of “incident solar radiation” was deflected, current global warming could be fully reversed.

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