“camped” out in Quebec, my son speaks better French than me and has corrected me all weekend, but we’ll see whose in charge when I poke him in the eyes two seconds before totality… Or squeal like a school girl as it approaches, we’ll see which happens!
Noticing a bit of misinformation here so let’s clear this up: take off your eye protection during totality. The corona is so faint you won’t see anything at all through eclipse glasses.
A minor accident had forced me down in the Rio de Oro region, in Spanish Africa. Landing on one of those table-lands of the Sahara which fall away steeply at the sides, I found myself on the flat top of the frustum of a cone, an isolated vestige of a plateau that had crumbled round the edges. In this part of the Sahara such truncated cones are visible from the air every hundred miles or so, their smooth surfaces always at about the same altitude above the desert and their geologic substance always identical. The surface sand is composed of minute and distinct shells; but progressively as you dig along a vertical section, the shells become more fragmentary, tend to cohere, and at the base of the cone form a pure calcareous deposit.
Without question, I was the first human being ever to wander over this . . . this iceberg: its sides were remarkably steep, no Arab could have climbed them, and no European had as yet ventured into this wild region.
I was thrilled by the virginity of a soil which no step of man or beast had sullied. I lingered there, startled by this silence that never had been broken. The first star began to shine, and I said to myself that this pure surface had lain here thousands of years in sight only of the stars.
But suddenly my musings on this white sheet and these shining stars were endowed with a singular significance. I had kicked against a hard, black stone, the size of a man's fist, a sort of moulded rock of lava incredibly present on the surface of a bed of shells a thousand feet deep. A sheet spread beneath an apple-tree can receive only apples; a sheet spread beneath the stars can receive only star-dust. Never had a stone fallen from the skies made known its origin so unmistakably.
And very naturally, raising my eyes, I said to myself that from the height of this celestial apple-tree there must have dropped other fruits, and that I should find them exactly where they fell, since never from the beginning of time had anything been present to displace them.
Excited by my adventure, I picked up one and then a second and then a third of these stones, finding them at about the rate of one stone to the acre. And here is where my adventure became magical, for in a striking foreshortening of time that embraced thousands of years, I had become the witness of this miserly rain from the stars. The marvel of marvels was that there on the rounded back of the planet, between this magnetic sheet and those stars, a human consciousness was present in which as in a mirror that rain could be reflected.
Well that is some spectacular prose, I am truly transported to a place where spirituality and science meet at a single point of grand mystery and realization that I have felt a few times in real life, alone in nature at surprising places and odd hours, but Saint-Exupéry has taken this all one further level up the rung.
To a level that my father actually lived, as an airplane pilot in Baja California back when the peninsula didn’t have a paved road, an isolated, remote place as yet mostly untouched by man.
One minor caveat, however:
a sheet spread beneath the stars can receive only star-dust
While I understand such a thoughtful writer was going for a feeling, surely with his talent he could have found a way to include windstorms, all the dust and sands they can sweep horizontally across the lands and over hills. The Rio De Oro region is in northern Morocco, surely it often gets blasted by powerful Saharan winds.
A sheet spread beneath the Moroccan sky most often receives desert-dust.
“Contrary to standard cosmological theories where the accelerated expansion of the universe is attributed to dark energy, our findings indicate that this expansion is due to the weakening forces of nature, not dark energy,” he continued.
The force of gravity is weak. And not just a little bit weak. It’s so much weaker than the other three fundamental forces—electromagnetism and the strong and weak nuclear forces—that it’s almost impossible to provide analogies.
Gravity isn’t a force. It’s the curvature of spacetime, the bending itself. You can’t compare it to the three other forces.
We can’t see the bulk, touch the bulk, experience the bulk, or otherwise interact with the bulk because our entire universe—all the particles and forces of nature—are restricted to life on the brane.
That means it isn’t falsifiable. It’s same as believing in god - it’s faith and not a scientific theory. Also the article says:
Physicists just need some way to pierce the veil of the brane and peer into the realm of the bulk.
How should physicists do that when by definition a bulk can’t be detected? In the later parts it is claimed that the bulk-brane-interactions somehow influences gravity and that this influence could be detected. I call bullshit.
If our running knowledge of gravity is mistaken
We know that our understanding of gravity is flawed because we can’t unify it with the theory of quantum mechanics. But there must be a link between them.
In 2019, the LIGO detector (…) measured gravitational waves emanating from the merger of a black hole with … something else. The black hole had a mass of around 23 solar masses. Its companion had a mass of only 2.6 solar masses. That’s far too small to be a black hole … but also a little too big to be a neutron star.
Objects with a mass above 2.5 solar masses are likely light weight black holes. Source
The whole article consists only of a lot of ‘could be’, nothing tangible and bullshit.
Gravity isn’t a force. It’s the curvature of spacetime, the bending itself. You can’t compare it to the three other forces.
I do agree but, it is very common in academia to disagree with this, to believe that the geometric representation of gravity is merely a clever trick to approximate gravitational effects, but that in reality it is caused by a force-carrying particle just like any other force, a graviton, and spacetime is flat. That was the basis of String Theory and some other views. I don’t know why this view is so popular but it is.
Just 6 light-years away, Barnard’s Star is a well-studied 10-billion-year-old M dwarf with a mass of 0.16 solar mass. Finding exoplanets around Barnard’s Star has been something of a white whale for astronomers for more than half a century; starting in the 1960s, researchers have claimed to have spotted various planets around Barnard’s Star, from distant Jupiter-mass companions to close-in super-Earths. Each of these claims has been refuted.
Now, the white whale appears to have been caught at last. Just last November, researchers reported the discovery of a planet orbiting Barnard’s Star with a period of 3.154 days. The data hinted at the presence of three other planets, but these candidates could not be confirmed. In a new research article published today, Ritvik Basant (University of Chicago) and collaborators leveraged years of data to confirm that Barnard’s Star hosts not just one, but four planets.
Good summary, but to everyone else reading this, it’s really worth it to read the article. It’s short and yet, frankly, fascinating. It discusses the methods used to identify the exoplanets and their orbital periods.
To think how hard it is to confirm these planets, for such a relatively close star. When we have already confirmed so much about objects at far greater distances.
Hard to comprehend these achievements from our individual perspectives. 👏
I wonder if Kepler or others would have found these planets had Barnard's Star been in the areas searched? I.e., very small planets in close orbits around a dim star is a very difficult target, period. This also means that the thousands of systems we now know about certainly have far more than the few bodies we've detected because we can only see the biggest ones well.
As someone who doesn’t know or understand any of this math/physics. Would you mind doing a super simple explanation of how the calculation works and why you chose certain factors?
Might be a dumb thing to ask but just curious and want to understand more.
D_nominal, D_min, and D_max represent the most likely, minimum, and maximum (well technically not maximum, just 3 standard deviations from most likely, of which 99.7% of trajectories will fall within) distance 2024 YR4 will pass from the center of the Moon (NOT the surface). They're taken from the linked NASA website. R_moon is the radius of the Moon.
L_impact is length of the impact corridor (the line where 2024 YR4 could impact the Moon). Since it doesn't pass through the center of the Moon, it's not simply 2*R_moon and so we need a simple formula to calculate it from R_moon and D_min.
P(x) is a probability density function; it's the black curve you can see. It shows, for a given trajectory along the line of possible trajectories, how likely 2024 YR4 is to follow that trajectory. It's shifted a bit from the center since the most likely trajectories are not exactly centered on the Moon. P_impact is the area of P(x) that falls within +/- L_impact, AKA the probability that the trajectory will intersect the Moon, AKA the impact probability.
The rest is just some graphing stuff that doesn't matter to the calculation.
AKA the probability that the trajectory will intersect the Moon, AKA the impact probability.
(Disclaimer, I know close to nothing about these) Am I pedantic about a useless detail or does it significantly change the probability if we consider that an object may still impact the moon after “missing it” if it comes close enough to be captured and come back after a semi orbit? Or do the relative speeds makes this extremely unlikely?
astronomy
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