Jaime Rudas's latest activity
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Jaime Rudas replied to the thread Undergrad Does the Alcubierre drive shorten distances?.No, what I'm referring to is the speed of light understood as the length of the path travelled by light in vacuum per unit of time. -
Jaime Rudas replied to the thread Undergrad Does the Alcubierre drive shorten distances?.So in curved spacetime the speed of light is not c?
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Jaime Rudas replied to the thread Undergrad Does the Alcubierre drive shorten distances?.By definition, a light-year is the length of the path travelled by light in vacuum during a time interval of one (Julian) year. From...
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.As a curious fact, it seems that Hubble never actually called it that. The earliest appearances of the term 'Hubble constant' that I...
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Yes, the Hubble constant ##H_0## is constant in space, not in time.
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Actually, that constant wasn't just 'invented' 100 years ago; it's a direct consequence of applying general relativity to a homogeneous...
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Yes, when we talk about cosmological distances, we generally refer to space-like separations between comoving objects.
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Another way to visualize what 70 km/s/Mpc is equivalent to is to show that something expanding at that rate will double its size in...
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Yes, but to measure the Hubble constant, you need to know the distances.
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Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.Redshift tells you the distance only if you already know the rate at which the universe is expanding.
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Jaime Rudas reacted to Filip Larsen's post in the thread Undergrad Help Understanding the Hubble Constant's Units with
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The linear expansion rate corresponds to around 7.1⋅10-11 1/year so you can get the "equivalent speed = distance/year" if you multiply... -
Jaime Rudas replied to the thread Undergrad Help Understanding the Hubble Constant's Units.If the Earth were expanding at the same rate as the current expansion of the universe, then two cities 1000 kilometers apart (Paris and...
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Jaime Rudas replied to the thread High School This One Moved Me.I believe that for a model of reality to be predictive, its fundamental principles must correspond to reality and its mathematical...
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Such is Mathematics.
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I think, at rock bottom, math is motivated by an abstraction of physical reality. Why that abstraction was chosen, and even why to...