Does this explain what generates gravity?

[Galu]

Just that it had been fun for humanity to "grow up" in a forgiving period

Homo sapiens emerged approximately 300,000 years ago. According to the graph below, that's about three ice ages ago!

Homo Sapiens can easily adapt to different climates and this talent has allowed us to survive through these dramatic climate events.

Indeed, as stated in Britannica, the history of humanity is integrally linked to climate variation and change.

However, I wonder if our increasing dependence on technology will help or hinder us to survive the next great climate event?

https://theconversation.com/how-man...-had-and-could-humans-live-through-one-179360

 

[Galu]

Galu's website reassured me that everything is going to be alright after all. Phew.

Did you take their Climate Quiz? https://co2coalition.org/climate-quiz/

As in our discussion on ice ages, the CO₂ Coalition takes the long term view.

 

[system7]

Yes I did. And most of the questions were quite irrelevant to Climate Change. Agricultural yields, size of Antarctic ice area, Numbers of Hurricanes. Whether Antarctic Ice melting is causing sea level rise. Etc.

A few blatantly misleading statements:

Actually it is true. But only up to the year 2000. The rate has now doubled. https://en.wikipedia.org/wiki/Sea_level_rise

I found some of the other stuff rather dubious too:

Should we be throwing all those old tyres, nuclear waste, plastic bottles, old microwaves and whatnot out in the street to let Nature recycle it?

It gets worse. Burning Oil and Coal for CO2 is Greening the Planet:

Who are these people? A collection of lobbyists for Oil and Mining interests, affiliated to the political machine. Some of the papers they cite are written by Dr. Happer who is on the board.

They even include a Nobel Laureate, but he is a Quantum Mechanics man, which is a red flag to me. The are Climate Change Deniers, and make money doing this.

https://en.wikipedia.org/wiki/CO2_Coalition


Sorry it's brutal. AS with other issues, deniers claim the right to debate Scientific Facts. In this case, there is no debate whatsoever. Only concensus.

https://en.wikipedia.org/wiki/Scientific_consensus_on_climate_change

99% of experts agree Climate Change is happening, and it's getting faster. Let's say between 50-80% of people in various countries agree. In the US it divides on party lines.


When it's 50C temperature on a summer day in some parts of the World, it isn't just a nice warm day. It's hell.

https://en.wikipedia.org/wiki/Heat_wave#Recent_examples_by_country_or_region

And your crops are going to die in the drought.

Your CO2 people are charlatans and snake-oil salesmen. Er, rant over.

 

[Galu]

Your CO2 people

They are not MY people. I am just as dubious about their agenda as you are.

I only came across them whilst searching for a clear ice age chart and, happily, theirs is in agreement with those from other sources.

I'd rather not get into discussions regarding man-made climate change.

 

[Galu]

P.S. Here's some balance from Scientific American - 'Ask the Experts: Does Rising CO2 Benefit Plants?'

https://www.scientificamerican.com/... of food production and better quality food.”

 

[system7]

Welcome to the Anthropocene Epoch.

https://en.wikipedia.org/wiki/Anthropocene

My particular bugbear and hobby horse, and this affects my Astro pics, as you know:

Only a Physicist and World Expert on the blue content of badly designed LED lighting can sort this mess out.

 

[Galu]

Only a Physicist and World Expert on the blue content of badly designed LED lighting can sort this mess out.

That strikes me as déjà vu!

Earlier in the thread we discussed dark-sky friendly LED lights such as the 590 nm Amber LED.

Note the absence of blue light in the Amber LED's spectrum.

 

[Galu]

Welcome to the Anthropocene Epoch.

Welcome...

And goodbye...

 

[Galu]

A couple of research papers that place doubt on our standard 'lambda cold dark matter' (ΛCDM) cosmological model got kinda lost over the festive season.

Here's one: https://academic.oup.com/mnrasl/article/537/1/L55/7926647?login=false

The authors claim that the 'timescape' cosmological model gives statistically superior results compared to ΛCDM in explaining Type Ia supernovae observations.

Here's a quick description of the two opposing models:

• ΛCDM: The Λ part stands for the 'dark energy' that the majority of astrophysicists say causes the accelerated expansion of the Universe.
• Timescape: This suggests that time passes more quickly in cosmic voids compared to where there is a concentration of matter, and hence gravity. This 'time dilation' effect causes the voids in the Universe to expand at an increasing rate.

The timescape model is seductive since it does away with the need for dark energy which is such a difficult concept to get our heads around.

However, I've just been listening to Dr. Becky suggesting that the latest support for the timescape model involves "cherry picking" of the supernova results.

Skip forward to 15:40 in her latest video:

 

[system7]

I don't know what leaves me feeling more tired, 25 minutes in the Swimming Pool. or 25 minutes of dear Dr. Becky having a non-stop rant...

She debunks the great Astrological alignment of 25th. January. Mentions that you have fat chance of seeing any meteors given a full Moon this month.

Casts doubt on the latest crackpot theory of Gravity and Dark Energy, and 38% time dilation in the Cosmic Void is a bit of a stretch IMO, given the Galactic Escape Velocity is a puny 400 km/s or so compared to c = 300,000 km/s....

Recall the Lorentz Transform is SQRT (1 - v^2/c^2), so this dilation is very small indeed.


I have heard about a sort of time dilation that keeps orbiting bodies like comets feeling a sort of constant velocity, even when they are obviously slowing down at perihelion:

https://math.ucr.edu/home/baez/gravitational.html

But this John Baez article about the LRL Vector and the Kepler Problem in 4 dimensions needs careful digestion before conclusions IMO. I don't understand it yet.


Bayes Theorem is a very useful thing indeed, being about the dangers of making statistical assumptions in biased samples.

Eddington was criticised for cherry-picking a photographic plate that supported his measurement of the bending of starlight in an eclipse.

Since observing conditions were terrible, this was no worse than me selecting the only picture I got of the Comet on a terrible murky night.

And subsequent observations backed up his ones anyway, so who cares?


With my usual economy in post number, a lesson that others could learn, I wish to resolve the matter of Blue Light content in Light Pollution:

A picture speaks a thousand words:

It is why even Warm LEDs have a glaring spectrum. This is a factor in the current fiasco enveloping the World's finest ground based telescope, the VLT which Dr. Becky is keen to book use of, more so than the JWST:

https://skyandtelescope.org/astronomy-news/will-chilean-observatory-lose-its-dark-skies/

The idiots want to build a "Green" industrial plant near it. Inevitably causing ruinous light pollution. Meeting general lighting regulations is not good enough here, IMO.


Sympathetic street lighting involves down-pointing light and warmer spectrum.

Before:

After, with light shades added:

Replacing Glare with useful lighting:

It's not hard, is it? Trouble is, my local Council is amongst the worst culprits.

 

[Galu]

She [Dr. Becky] debunks the great Astrological alignment of 25th. January. Mentions that you have fat chance of seeing any meteors given a full Moon this month.

And warns about the hype that will appear regarding these events, which I already see happening on YouTube. Good for you Dr. Becky!

With my usual economy in post number, a lesson that others could learn

On the contrary, I feel that including a multitude of different topics in the one post can only discombobulate the reader.

It's not hard, is it?

It's hard in the respect that local authorities are hard strapped for cash!

 

[benb]

She debunks the great Astrological alignment of 25th.

Youtube in its infinite wisdom hasn't fed me Dr. Becky videos lately, but I did see a recent headline about a planetary alignment. I'm reminded of the book "The Jupiter Effect" from circa 40 years ago about a similar (ahem, "once in a lifetime") alignment that was supposed to do something gravitationally and cause huge, devastating earthquakes and such. I don't recall any such effects. Of course the other planets' gravity is insignificant compared to the Sun and Moon, but it sold a lot of books.

 

[Galu]

I'm reminded of the book "The Jupiter Effect"

I just had to look it up!

https://en.wikipedia.org/wiki/The_Jupiter_Effect

 

[mchambin]

Thanks for the fun, I love these junck science theories. As a Science Fiction fan, I am not interested to read this book.
The planet alignement end of the world is an ever lasting crackpot recurrent topic.

 

[Galu]

I'd be interested to know what Asimov had to say in his foreword to The Jupiter Effect.

If anyone had the wherewithal to debunk the premise of the book, surely it was he?

Books, movies & Netflix series full of apocalyptic doom & gloom. Dontcha just love them!

 

[TNT]

Uvgeotcha... 😉

//

 

[indianajo]

Lets worry about something real. The 10000s that will die and 10000 buildings that will collapse when the San Andreas fault slips. PBS Nova said sediment analysis shows it produces a big one about every 700 years. Same sediment indicates is last did it about 450 years ago. LA is about 10 miles away, on the subduction side of the fault. North American plate starts up in the hills east of LA.

 

[Galu]

Fortunately, the chances of a Yellowstone 'supereruption' are exceedingly small in the next few thousands of years.

 

[wg_ski]

Wildfires will probably chase anyone with a brain out of California in way less than 250 years.

 

[system7]

According to the BBC, some Californian folks have already cleared off to places like Duluth, Minnesota. Which sounds cold to me!

And in the North of the UK, a million are without power due to a nasty little storm called Eowyn. Just in time for the Planetary conjunction tonight, the 25th January!

I hope Galu is alright.... I was hoping for his 12th enlightening post on this page.

Ever the diligent fact-checker, I have located "The Jupiter Effect" which explains all this woefulness in Portsmouth Library:

Sometimes a book serves as a time capsule, capturing the anxieties and scientific debates of its era. The Jupiter Effect is one such book. The revised 1976 edition builds on the original 1974 prediction: a rare planetary alignment in March 1982 would supposedly unleash catastrophic events on Earth, from massive earthquakes to extreme weather. Gribbin and Plagemann hypothesized that the gravitational pull of the aligned planets could disrupt Earth’s rotation and trigger disasters, with the San Andreas Fault often identified as ground zero.

Unlike sensationalist works of pure pseudoscience, The Jupiter Effect was rooted in real scientific ideas, particularly astrophysics and geophysics. John Gribbin was an astrophysicist and editor for Nature, one of the leading scientific journals, and Stephen Plagemann completed his doctoral work under the eminent astronomer Sir Fred Hoyle. Both likely believed their hypothesis warranted serious attention, though its flaws quickly became apparent.

The book’s bold claims were met with intense scrutiny from the scientific community. Critics called it “pure astrology in disguise.” The underlying premise—that planetary alignments could exert enough gravitational force to affect tectonic plates—was ultimately shown to be negligible. Even Gribbin and Plagemann acknowledged the flaws in their theory, publishing The Jupiter Effect Reconsidered in 1982, where they revised their stance and cited the 1980 eruption of Mount St. Helens as evidence of their ideas, though this too failed to convince most scientists.

Adding to the intrigue is the book’s preface by Isaac Asimov. In his signature style, Asimov provided a compelling history of earthquakes and their devastation but stopped short of endorsing the authors’ predictions. His inclusion lent credibility and captured the public’s imagination, even as the scientific community remained skeptical.

I purchased this book not for its scientific merit but for nostalgia. Reading it transported me back to the early 1980s, when these ideas were the talk of my high school astronomy club. My most vivid memory is attending a star show at the Hansen Planetarium in Salt Lake City shortly before the planetary alignment. The show mirrored the book’s narrative, detailing the alignment and its supposed consequences, but ultimately debunked the hypothesis. It walked audiences through the science, showing why the dire predictions were overblown. I left with a greater appreciation for planetary mechanics—and a chuckle at humanity’s tendency to leap to doomsday scenarios.

Though its predictions didn’t come to pass, The Jupiter Effect remains a fascinating piece of scientific history. It highlights how bold, speculative ideas can capture the public imagination—even when the science doesn’t hold up. Today, it serves as a reminder of the importance of critical thinking and skepticism, particularly when bold claims about natural disasters arise.

I don't think I shall risk life and limb and venture out with the Stars aligned so badly..

No. I am contemplating Black Hole Math from the safety of Home:

https://spacemath.gsfc.nasa.gov/blackholes.html

Did you know that if the Moon and Earth were a Black Holes, they would look like this?

But the Gravity would be the same, so if you got within a thousand miles of the Black Hole Earth, it would flatten you!

I have also been reading Richard Feynman on Spacetime distortion. The radius excess on the Earth is a puny 1.5mm, but for the Sun it is 0.5km.

https://www.feynmanlectures.caltech.edu/II_42.html

There is a formula for this in terms of 2GM / c^2 and you will spot it is 1/6th of the Schwarzchild radius of near 3km for the Sun.

I wonder what it means?