Showing all posts tagged: astronomy

The physics of running and keeping fit on the Moon

8 July 2024

Rhett Allain, writing for Wired, looks at the physics of this important question.

If humanity is ever to establish bases on the Moon, ways of keeping occupants fit in the low lunar gravity need to be worked out. A wall of death sort of gizmo, that’s a little like a stationary hamster-wheel, but turned on its side, that emulates Earth-like levels of gravity, may be a solution. But there might be more effective alternatives.

But check out the article’s artist impression of a suited up astronaut “jogging” on the surface of the Moon. Straight up running in this way is a fanciful keep fit option unfortunately, as simple as the idea may at first seem. It’s too bad though, because what a sight it would be to behold: Earth floating in the lunar sky, as you ran.

I doubt Earth would be quite as big as depicted in Nzoka John’s image, but it still be quite the spectacle. And on the subject of what Earth might look like from the surface of the Moon, a gallery of images by American illustrator and writer Ron Miller, depicting how other planets in the solar system would appear from Earth, if they were as close as the Moon.


, , , ,

Potentially habitable Earth size planet forty light years away

4 July 2024

That’s the good news. Tory Shepherd, writing for The Guardian, says the recently discovered exoplanet, dubbed Gliese 12b, might be able to host liquid water. We all know what that means. If there’s water, there may be life. Gliese 12b is so named because it orbits a star called Gliese. Now for the bad news. Gliese is a red dwarf.

I personally don’t have a problem with red dwarf, or M-type, stars. They’re actually kind of cool. And common. Up to seventy-five percent of stars in the cosmos are thought to be red dwarfs. The star nearest to Earth, Proxima Centauri, is a red dwarf. And while most stars in the universe have relatively short lifespans — for instance the Sun, which is about half way through its ten billion year life — red dwarfs live for trillions of years.

The last stars — as we currently understand them, at least — shining in the universe, will be red dwarfs. Go the red dwarfs. But, the problem is any planets orbiting in a red dwarf’s habitable-zone, will be tidally locked. That is, only one side of the planet will face its host star. That half of the planet therefore, in this case Gliese 12b, will be overly warm, while the other, dark side, will be rather cold.

This may not be particularly conducive to life. But some scientists have suggested life on planets orbiting red dwarfs in the habitable-zone, may take hold near the day-night terminator. This is where it will be neither too hot, nor too cold. But this would be an extremely narrow corridor, somewhat limiting the chances of life, especially intelligent life, developing.

Then there’s the red dwarfs themselves. They’re prone to regularly emitting intense radiation flares, which could have the effect of sterilising the surface of nearby planets. This points to the likelihood of Gliese 12b not being all that habitable at all. I think we need to reserve our excitement for the discovery of habitable Earth size planets, for maybe when they’re found orbiting other types of stars.



Did the universe exist before the Big Bang? Maybe…

27 June 2024

What happened, or was there, before the Big Bang that is said to have brought the universe into being? Was there nothing, to which something came? It is the question of the ages.

In his recent documentary series, Universe, British physicist Brian Cox posits that the universe existed before the Big Bang. How long this pre Big Bang entity had been there, or its origins, remain unknown however. How fascinating these before-the-beginning sort of questions are.


, , ,

The search for the distant Planet Nine continues

27 May 2024

Weird stuff is happening out on the remote boundary of the solar system. Beyond the orbit of Pluto. You name it, it’s going on out there. Irregularities. Anomalies. Clustering of apsidal lines. Perihelia. And — saving the best for last — a surprising prevalence of retrograde Centaurs.

These anomalies include the apparent clustering of apsidal lines of long-period trans-Neptunian object (TNO) orbits, the alignment of their orbital planes, the existence of objects with perihelia extending far beyond Neptune’s gravitational influence, the highly extended distribution of TNO inclinations, and the surprising prevalence of retrograde Centaurs. Collectively, these irregularities hint at the existence of a yet-undiscovered massive planet, tentatively named Planet Nine (P9), whose gravitational influence sculpts the outer reaches of trans-Neptunian space (Batygin et al., 2019).

But this is nothing new. Astronomers have been aware of this activity for some time.

Many postulate this weirdness points to the existence of an — as yet — undiscovered, large-ish planet, out beyond the known planets of the solar system. Some incredible distance out beyond the known planets. Planet Nine, if it exists, is thought to be orbiting the Sun at an approximate distance of twenty times that of Neptune to the Sun.

The gravitational influence of Planet Nine, combined with its extreme distance from the Sun, is enough to interfere with what would otherwise be predictable orbits of the numerous TNO objects, of which Pluto is one.

Planet Nine sort of comes along and displaces — sweeps aside, perhaps — these TNOs. While the presence of a larger planet therefore appears to be the logical explanation for the various irregularities and anomalies witnessed in the outer solar system, scientists are yet to clap eyes the elusive body. Or even calculate its position mathematically, for that matter.

If Planet Nine is found, here’s hoping one of Earth’s space agencies dispatches a probe pronto to go and take a good look at it.



Extraterrestrials may arrive in 500 years, but not in flying saucers

30 April 2024

In the late 1960’s, former United States President Jimmy Carter, reported seeing an Unidentified Flying Object (UFO). Today unexplained objects, or phenomena, seen in the skies, are referred to as Unidentified Anomalous Phenomenon (UAP). Carter, however, was not expecting to participate in any historic close encounter of the third kind:

While puzzled by the object and its origins, Carter himself later said that, while he had considered the object to be a UFO — on the grounds it was unexplained — his knowledge of physics had meant he had not believed himself to be witnessing an alien spacecraft.

Some people may be unhappy that Carter allowed physics to get in the way of a good story. Because wouldn’t it be great if we could whiz about the galaxy in a vessel the size of the average suburban house, which every other intelligence in the galactic neighbourhood seems capable of, except us.

House-size flying saucers defy the laws of physics, because, you know, their builders seemingly are able to defy the laws of physics. It would however be awesome to zap back and forth to say the nearest star system, Alpha Centauri, in a house-size vessel that could travel (presumably/somehow) faster than the speed of light. At least I’m not breaking the laws of dreaming there.

But if close-to-light-speed interstellar travel, together with the possibly of extraterrestrials visiting Earth (from the far side of the Milky Way, no less) intrigues you, read this Twitter/X post, by American physicist Casey Handmer. Visitors from civilisations, from maybe fifty thousand light years across the galaxy, may be mere centuries away from reaching our solar system:

Let’s say that any civilization that can figure out interstellar travel can develop from slow to 99% of the speed of light in 500 years, and they’re coming from the other side of the galaxy — 50,000 years ago. By the time the light of their first (presumably highly energetic, fireworksy) relativistic travel reaches us, they’re already 99% of the way here – just 500 years to roll out the welcome mat.


, ,

Extra-terrestrials may not want Earth as part of their galactic empire

19 April 2024

A conquering interstellar civilisation could bring the entire galaxy under its yoke in about a million years, assuming said civilisation could traverse the Milky Way at about ten percent the speed of light. I expect it’d be a multi-generational undertaking.

It’d also be up to those who conceived of the original vision to conquer the galaxy, to find a way to keep their descendants motivated. A million years is a long time.

This might be one reason why we’ve not encountered any extra-terrestrial lifeforms so far. No one has the energy to invade the whole galaxy, so they’ve stayed in their corner, undetected. But there is another possibility. The all-powerful invaders are being picky.

They’re only acquiring sections of the Milky Way, and the planets in those regions, that are of some sort of value to them. Perhaps Earth is not in that category.

This is the upshot of the latest Kurzgesagt video presentation. An interesting theory. We are not alone, but we are not wanted.


, ,

Is the Sun conscious? Can a great ball of fire think for itself?

5 April 2024

Maybe I’ve been watching too much of Universe, the Brian Cox made documentary about, well, the universe, and am way too willing to take in all manner of ideas, no matter how outlandish they may seem. So when this article (PDF), exploring the possibility the Sun is a conscious entity (of some sort), written in 2020 by Rupert Sheldrake, appeared on my news feed recently, my curiosity was piqued.

Meanwhile, field theories of consciousness propose that some electromagnetic fields actually are conscious, and that these fields are by their very nature integrative. When applied to the sun, such field theories suggest a possible physical basis for the solar mind, both within the body of the sun itself and also throughout the solar system. If the sun is conscious, it may be concerned with the regulation of its own body and the entire solar system through its electromagnetic activity, including solar flares and coronal mass ejections. It may also communicate with other star systems within the galaxy.

If the Sun could talk, what might it say to us? Maybe, “do something about climate change before it’s too late.” Or, “always wear sunscreen when in my presence.”

It’s a fun idea, solar consciousness, but I’m not sure we’d ever hear Brian Cox going along with the notion. I’ll defer to Star Trekin’! in the meantime: it’s consciousness; but not as we know it…


, , ,

An app that points to centre of the Milky Way galaxy

26 March 2024

Night sky and stars seen through gap in a rock canyon, photo by Pexels.

Image courtesy of Pexels.

Tangentially related to my previous post… product designer and technologist Matt Webb has created an app, named Galactic Compass (link to Apple app store), that points to the centre of the galaxy.

When on the (far less light polluted) NSW Central Coast, I can kind of look down from the tail of the constellation Scorpius (the scorpion), and be observing the right patch of the night sky.

When back amongst the super bright lights of Sydney though, that can be a little trickier. Like, find a star, any star, let alone the Scorpius constellation.

Read also Galactic Compass’ origin/development story, the app was built with help from ChatGPT.


, , ,

A patch for computer software one light-day away on Voyager 1

25 March 2024

One of the computers on NASA’s deep space probe Voyager 1 is experiencing some sort of malfunction, with recent signals from the probe containing no usable data. Mission engineers are apparently confident the problem can be resolved, even though Voyager 1 is almost a light-day distant, meaning it’ll take time to apply a fix:

Because Voyager 1 is more than 15 billion miles (24 billion kilometers) from Earth, it takes 22.5 hours for a radio signal to reach the spacecraft and another 22.5 hours for the probe’s response to reach antennas on the ground. So the team received the results of the command on March 3. On March 7, engineers began working to decode the data, and on March 10, they determined that it contains a memory readout.

Although Voyager 1, and deep space counterpart Voyager 2, have left the solar system and are in interstellar space, it is estimated it will take Voyager 1 another three hundred years to reach the Oort cloud. The vastly scattered debris, rocky remnants of the formation of the solar system, that constitutes the Oort cloud, may extend more than two light years from the Sun. That’s about half way to the nearest star system, Alpha Centauri.

So to be truly beyond the solar system, I imagine the Voyager probes will need to clear the Oort cloud first. We might be waiting sometime for that to happen. It’s incredible the way mission controllers can keep tabs on deep space missions though, and trouble shoot, and perhaps remedy problems, despite their distance from the Sun.

About twenty years ago, scientists were puzzled by changes in the trajectories of deep space probes Pioneers 10 and 11. Somehow both craft, then located in the Kuiper belt, which is situated beyond the orbit of Neptune, appeared to have slowed down slightly. All sorts of theories were advanced to account for the anomaly, including the idea that gravity may be behaving in ways not seen before.

After analysing gargantuan quantities of data, mission engineers determined that heat loss was having a subtle influence on the movements of the probes, in that it was acting a little like a brake. Contact with both vessels had been lost by that stage, so even if a fix could have been devised, it unfortunately could not have been applied.


, ,

To go where no one has gone before, the limit of the universe

22 March 2024

German animation and design studio Kurzgesagt have been producing excellent informative and educational videos for what seems like half the lifespan of the universe. Let’s hope Peak-Kurzgesagt is a situation that never comes to pass.

Their latest video, the Paradox of an Infinite Universe, covers some heady ground; the concept of a physical edge, or boundary, to the universe. If we could somehow reach such a region, could we press our hand against it, as we can a garden wall? Hmm…


, ,