In a remarkable achievement, China has successfully collected samples from the far side of the moon, marking a significant milestone in space exploration. The Chang'e-6 mission, launched on May 3, touched down in the Apollo crater within the vast South Pole-Aitken basin on June 1. During its brief but productive stay, the spacecraft gathered approximately 2 kilograms of lunar material using a scoop and drill. The samples, now stored in an ascent vehicle, are expected to return to Earth on June 25, landing in Inner Mongolia. This historic achievement not only demonstrates China's space program prowess but also provides scientists with a unique opportunity to unravel the mysteries of the moon's formation and evolution. Achievements: - *First-ever samples from the far side*: Chang'e-6 successfully collects lunar material from the moon's less-explored hemisphere. - *Second successful farside landing*: China builds on its 2019 achievement with...
One of the greatest scientific successes of the past century was the theory of the hot Big Bang: the idea that the Universe, as we observe it and exist within it today, emerged from a hotter, denser, more uniform past. Originally proposed as a serious alternative to some of the more mainstream explanations for the expanding Universe, it was shockingly confirmed in the mid-1960s with the discovery of the “primeval fireball” that remained from that early, hot-and-dense state: today known as the Cosmic Microwave Background.
For more than 50 years, the Big Bang has reigned supreme as the theory describing our cosmic origins, with an early, inflationary period preceding it and setting it up. Both cosmic inflation and the Big Bang have been continually challenged by astronomers and astrophysicists, but the alternatives have fallen away each time that new, critical observations have come in. Even 2020 Nobel Laureate Roger Penrose’s attempted alternative, Conformal Cyclic Cosmology, cannot match the inflationary Big Bang’s successes. Contrary to many years of headlines and Penrose’s continued assertions, we see no evidence of “a Universe before the Big Bang.”
The Big Bang is commonly presented as though it were the beginning of everything: space, time, and the origin of matter and energy. From a certain archaic point of view, this makes sense. If the Universe we see is expanding and getting less dense today, then that means it was smaller and denser in the past. If radiation — things like photons — is present in that Universe, then the wavelength of that radiation will stretch as the Universe expands, meaning it cools as time goes on and was hotter in the past.
At some point, if you extrapolate back far enough, you’ll achieve densities, temperatures, and energies that are so great that you’ll create the conditions for a singularity. If your distance scales are too small, your timescales are too short, or your energy scales are too high, the laws of physics cease to make sense. If we run the clock backward some 13.8 billion years toward the mythical “0” mark, those laws of physics break down at a time of ~10-43 seconds: the Planck time.
At the same time, there were observations that were no doubt true, but that the Big Bang had no predictive power to explain. The Universe allegedly reached these arbitrarily high temperatures and high energies at the earliest times, and yet there are no exotic leftover relics that we can see today: no magnetic monopoles, no particles from grand unification, no topological defects, etc. Theoretically, something else beyond what is known must be out there to explain the Universe we see, but if they ever existed, they’ve been hidden from us.
The Universe, in order to exist with the properties we see, must have been born with a very specific expansion rate: one that balanced the total energy density exactly, to more than 50 significant digits. The Big Bang has no explanation for why this should be the case.
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