Posted on 07/26/2023 10:33:46 AM PDT by MtnClimber
Dismantling the belief in a static universe, Edwin Hubble's revolutionary observations in the 1920s laid the groundwork for our understanding of a continually expanding cosmos. However, we must seek to reconcile this theory with observations that are consistent with a non-expanding universe, writes Tim Anderson.
You have been taught that the universe began with a Big Bang, a hot, dense period about 13.8 billion years ago. And the reason we believe this to be true is because the universe is expanding and, therefore, was smaller in the past. The Cosmic Microwave Background is the smoking gun for the Big Bang, the result of a reionization of matter that made the universe transparent about 300–400,000 years after the Big Bang.
How did we go from Einstein modifying his equations to keep the universe static and eternal, which he called the biggest blunder of his life, to every scientist believing that the universe had a beginning in 10 years? It all started with astronomer Edwin Hubble using the most powerful telescope at the time on Mount Wilson in California. At the time, in the 1920s, scientists believed that the Milky Way galaxy was the totality of the universe. Objects in the night sky like Andromeda that we now know are galaxies were called “nebulae”.
Looking at these objects, however, Hubble knew how bright particular stars called Cepheid variables were supposed to be. Knowing how bright they were supposed to be meant that he could tell how far away they were. He found to his surprise that Andromeda and Triangulum had Cepheid variables that were too far away to be inside the Milky Way. They weren’t nebulae. They were galaxies.
Hubble’s discoveries, made in 1924, merited a short column on page 6 of the New York Times. In that article, “Dr. Hubbell” was said to have shown that nebulae are in fact “island universes”. The concept was so new that they weren’t even recognized as galaxies. Hubble was able to estimate distances for his newly discovered galaxies. His estimates were off by about a factor of 7 but proportionally correct. Other scientists such as Vesto M. Slipher, had been busy, since 1912, measuring how fast the galaxies he identified were moving towards or away from us by measuring their redshift.
The way you measure redshift uses a concept from atomic theory called spectroscopy. Basically, stars contain elements that absorb light at specific wavelengths. These are patterns of missing wavelengths in the spectrum of the light called absorption spectra. These patterns show up because the atoms contain electrons that absorb photons with particular frequencies. When the photon strikes the atom, the electron absorbs it and moves to a higher orbital, but only if it has the exact frequency needed for that electron. Otherwise, no absorption happens. This property can be used to determine what things are made of by exposing them to light and measuring their emissions. It can also be used to make lasers.
Spectrum of the star Altair from NASA, ESA, Leah Hustak (STScI).
In astronomy, it is how we determine how fast objects are moving towards or away from us because of something called the Doppler effect. If something is moving away from us, the wavelengths of light coming from that object will be stretched out which makes them longer and lower frequency. This shifts the absorption spectrum to the right in the above picture and so is called redshift since the right side is red. If the object is moving towards us, then it will be shifted to the blue side and so is called blueshift. The same thing happens with sound which is why a siren has a higher pitch as an ambulance moves towards you and a lower pitch when it moves away from you.
Since we know what the frequencies in the absorption spectrum are supposed to be for particular elements and we can, by the pattern and what we know about stars, identify what those elements should be. We can determine how redshifted stars and galaxies are. When Hubble looked at all these new galaxies he had identified, he made a correlation between their velocity based on redshift and their distance based on the Cepheid variables. It turns out that these were linearly correlated. In other words, the further away a galaxy was, the faster it moved away from us. You can make a graph with speed on the vertical axis in km/s and distance on the horizontal axis in Megaparsecs (about 3.26 million lightyears) and you will find that it makes a line.
Hubble identified the slope of this line as a universal constant which we now know as the Hubble constant. His value was about 500 km/s/Megaparsec. If you correct for his factor of 7 error in distance, this falls within the currently accepted value of 68–74 km/s/Megaparsec. Alexander Friedmann in 1922 and Fr. George Lemaître independently in 1927 had used Einstein’s field equation to predict that the universe should be expanding (or shrinking). Combining their results with Hubble’s observations and the successful demonstration of the correctness of Einstein’s equations within the Solar System, scientists concluded that the universe was expanding.
Not everyone was happy about this conclusion. That included Hubble himself. Hubble disagreed with the interpretation of his data believing that redshifts might not be related to velocity at all and he criticised the popularity of the expanding universe theory, saying in the Journal of the Royal Astronomical Society in 1937:
The interpretation of red shifts by the theory of the expanding universes is so plausible and so widely current that, in making a delicate test of the theory, it is desirable to push uncertainties in the favourable direction before admitting a discordance.
He had good reason to believe in a discordance because, based on his data, the universe would have been younger than the Earth, too small and dense by far, with a “closed” geometry implying it should fall back in on itself. This turned out to be wrong because Hubble had vastly underestimated the distances to the galaxies he had observed. The universe was actually far older and less dense than he believed.
Ping
Open Universe or Closed Universe - does the universe expand forever or eventually collapse due to gravity.
Expanding Universe or Static Universe and is there expanding space-time - Is the universe expanding or is it essentially fixed with unknown things that make it look like it is expanding. And is the fabric of space expanding.
Only God knows.
You are a fluke of the Universe
You have no right to be here
And whether you can hear it or not
The Universe is laughing behind your back
One of the craziest things over these last few crazy years has been watching physics at both ends (subatomic and cosmological) completely fall apart.
Wrong again? Maybe stop funding the pop interpreters of settled science...they are always saying things like “we know”, “ truly” and other assertions of certitude.. they need to say something like, “ as far as we THINK we know it might be that blah, blah, blah...but we could be incorrect...” Time to turn off the false narrative spigots..
The more we know, the more we realize the things we don't know. So I think you are right.
Yes we could be.
Don't pose that question to your ex-wife (for those who have them). I can tell you in advance what the answer will be.
Everything?!?
.
Yuppers
But We are getting Closer to the TRUTH.
That's where we went wrong. Gravity stretches and compresses space/time. What we're seeing isn't necessarily an expanding Universe driven by a Big Bang... It's a pulsing, moving, stretching, and even in extreme cases possibly even knotting itself Universe. Constantly being shredded by black holes and recycled via perturbation theories virtual particle pairs...
Lather. Rinse. Repeat.
If a man is alone in the woods, and his wife isn’t around to hear him, is he still wrong?
If it's expanding, what is it expanding into?
If it's not expanding, what lies beyond the furthest edge? Is there just a big wall, and the universe is just contained in a big box?
I doubt we will ever know....
My EX is renting a room in a single wide trailer out in the desert.
.
I’m not bitter and I wish her well.
The attempted deliberate undermining of "science" -- often driven by political objectives -- continues to accelerate. Then again, these are two very different things: Science vs. Political Science, both of which have been around for a long time. The political goal is, as with so many other terms (e.g., "immigrant"/"illegal alien"; "gender"/"sex" to mention but two), to conflate the terms and sow confusion, confusion being a necessary element to achieve a much larger political objective: replace our Republic with a totalitarian government). It all fits if you think about it.
Yep, very confusing. Is the universe flat? Could we fall over the edge?
I am sure global warming is causing clumps hydrogen gas to undergo thermonuclear fusion in our galaxy and that we are harming other galaxies the same way, faster than the speed of light.
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