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Visualization of the whole observable universe.The inner blue ring indicates the approximate size of the Hubble volume. In cosmology, a Hubble volume (named for the astronomer Edwin Hubble) or Hubble sphere, Hubble bubble, subluminal sphere, causal sphere and sphere of causality is a spherical region of the observable universe surrounding an observer beyond which objects recede from that ...
Do early dark energy models resolve the Hubble tension? [25] [32] Baryon asymmetry: Why is there far more matter than antimatter in the observable universe? Cosmological constant problem: Why does the zero-point energy of the vacuum not cause a large cosmological constant? [33] [34] Size and shape of the universe:
H 0 is Hubble's constant and corresponds to the value of H (often termed the Hubble parameter which is a value that is time dependent and which can be expressed in terms of the scale factor) in the Friedmann equations taken at the time of observation denoted by the subscript 0. This value is the same throughout the universe for a given comoving ...
Hubble radius, Hubble sphere (not to be confused with a Hubble bubble), Hubble volume, or Hubble horizon is a conceptual horizon defining the boundary between particles that are moving slower and faster than the speed of light relative to an observer at one given time. Note that this does not mean the particle is unobservable; the light from ...
Two years later, Hubble showed that the relation between the distances and velocities was a positive correlation and had a slope of about 500 km/s/Mpc. [10] This correlation would come to be known as Hubble's law and would serve as the observational foundation for the expanding universe theories on which cosmology is still based.
The observable universe is a spherical region of the universe consisting of all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.
The aim is to find so-called M Dwarfs, stars 20 times dimmer than our sun, and see if they emit too much radiation to support life on other worlds. Mini-Hubble will scan dim stars to see if they ...
The current density of the observable universe is of the order of 9.44 · 10 −27 kg m −3 and the age of the universe is of the order of 13.8 billion years, or 4.358 · 10 17 s. The Hubble constant, H 0 {\displaystyle H_{0}} , is ≈70.88 km s −1 Mpc −1 (The Hubble time is 13.79 billion years).