and I hope the attempt to lift the Swift telescope to a higher orbit is successful
if you really want to stay on top of what is breaking astrophysics in realtime, I highly recommend following DrBecky on youtube or elsewhere, she is fantastic
It’s like a Dunning-Kruger effect on a field-wide scale, but in a good way. Rather than an example of hubris, it’s an opportunity for awe.
what makes us so certain that we can trust what we see on James Webb? Can we definitely discard a measurement problem?
In Hubble, that fuzz was marked. With Webb, far less so.
I think these are real true positives
If they exist, they would not be constrained to stellar mass and above. There could be a population of little black holes floating around. Anything under the mass of a decent size asteroid would have evaporated by now but anything that mass and above would still exist.
They are a dark matter candidate, and one that doesn’t require new physics. But even if they don’t account for a significant amount of dark matter they still probably exist.
The most exciting thing about PBHs is that one or more may exist in our solar system. They might have been captured over billions of years. Finding them would be incredibly challenging, especially if they are low mass, but if we did it means we could directly examine and experiment on a black hole.
It could be something with the mass of a large asteroid but the size of a hydrogen atom. We could only find it by its gravitational effects. It would be utterly invisible otherwise unless it encountered matter and even then there might only be a tiny gamma ray flash, a nano accretion disc that lasts femtoseconds. We might also find smaller objects that appear to be orbiting nothing and find it that way.
Directly accessing one could allow us to test theories of quantum gravity and things like string theory, and maybe more. A black hole could be like a Rosetta Stone of deep fundamental physics.
The film Interstellar involved using plot magic to visit a black hole and solve physics, but this would allow it for real. It would just be an itty bitty one.
What are the current theories explaining the early universe? What happened to the Big Bang? I only studied astronomy up to an undergraduate level, so I don't really know.
I imagine that various non-uniform gases were scattered around, and due to spatial distortions, those uniform gas regions clumped together, forming stars and other structures. Perhaps the expansion of space wasn't uniform either—it expanded unevenly, sometimes bulging, and when space expands or contracts, energy is generated, causing spacetime changes to shake the field, and that shaking might have created matter. Maybe the dynamic interaction between changing spacetime and fields revealed the energy stored in the field in the form of particles.
What do scientists think about this in modern cosmology? My knowledge is far too limited and I lack intuition, but reading science-related articles always excites me. Maybe it's because I still have some childlike curiosity left in me
• Big Bang: we can only see back to surface of last scattering, i.e. the CMB, extrapolating backwards goes "???" at much the same point as it did a few decades back because we still have not unified quantum mechanics and general relativity
• CMB should only have isotope distribution of Big Bang nucleosynthesis, that hasn't changed in the last decades, dunno if that's what you meant by "various non-uniform gases were scattered around"?
• Variations in density of CMB do exist, key phrase is "Baryon acoustic oscillations", while they're very small magnitude they're also massive in distance scale, so they're how galactic clusters formed (that scale rather than stars directly): https://en.wikipedia.org/wiki/Baryon_acoustic_oscillations
https://www.youtube.com/watch?v=PPpUxoeooZk
https://www.youtube.com/watch?v=LRUTnoveZs8
• Re: "Perhaps the expansion of space wasn't uniform either": I heard about specifically "Timescape Cosmology", but a quick search says that's part of a broader category of inhomogeneous cosmologies: https://en.wikipedia.org/wiki/Inhomogeneous_cosmology#Timesc...
https://www.youtube.com/watch?v=SXg6YVcdOcA
https://www.youtube.com/watch?v=JlNVZz5D6WE
• Re: "and when space expands or contracts, energy is generated": no, general relativity does not in general conserve energy, and it is related to the curvature of spacetime. Simple example is that the photons in the CMB have much less energy to us than they did to the atoms they were emitted from**: https://www.youtube.com/watch?v=04ERSb06dOg
* I assuming I'm correctly judging the level and attention to detail they're providing, given the detail they put in and references to specific research publications. My degree is Software Engineering.
** There's also a Veritasium video about this, but to me Veritasium feels like a BBC 2 evening popular science show, so I'm not as confident about recommending it.
I don't know what conditions were like before that stage, but like Eric Idle says, nothing can come from nothing.
Dark energy is a horse shit name for a theory that was horse shit to begin with. The Universe is probably just inhomogeneous, like your intuition is saying.
It’s like a comment in your code like \\ TODO…
I don’t see why that’s that hard, or why we’d expect to instantly be able to figure everything out.
This subtitle really bothers me. Science isn't about finding out what is true. Science is about finding out what is false and building models to explain the rest. We can never confidently say we know something to be true because that closes the door for future science to disprove our beliefs and that's exactly the purpose of science.
The best we can do is come up with increasingly more useful models accepting that in the end all models are wrong but different models are useful for different purposes.
Science can do a decent job of disproving a hypothesis because even a single contradiction should be enough to suffice in good science, but it's far less efficient at proving anything true even if it seems to always be true. For instance mathematical relationship describing the gravitational attraction between large bodies seemed to always work, but it turns out it was merely a rough approximation that completely fails in various cases such as when one body has a particularly large gravitational pull, or when very high relative velocities are present. And even modern understanding is, at best, another rough approximation because we can already see endless examples in the cosmos of examples that defy current understanding and require further refinements in a direction that's currently unknown.
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Basically at any point in history if you look at the bleeding edge science from a century before, it looks naive in many ways. In each era people always think they have finally moved beyond this, but we never have and it's entirely possible we never will since it's likely this universe has surprises awaiting us that we can't even yet imagine. Think about how utterly bizarre it is that time itself is a relative variable meaning with tech capable of reaching sufficiently high velocities you can literally travel into the future, relative to people at rest (such as all of Earth for example). It's nonsense, but it's completely real.