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?
I’m confused about what exactly the ring is in the image or the main image at least. There seems to be an enhanced image in the article that highlights the ring more clearly as an outer edge, which makes sense (I suppose).
But I don’t understand what I’m to make of the top image. It’s the diffuse light part of the ring?
astronomy
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