Pegajace
Pegajace t1_jeczwq8 wrote
Reply to comment by ForestCityWRX in ELi5 If the universe is expanding, what is it expanding into? by cashmoneyhash
You're still thinking of space as if it's some material existing within space, but that's a fundamental error. Space isn't occupying space, and it's not at a location within itself or anything else. Space is what matter & energy occupies, and what separates locations & events via both distance & time.
> What is there before space is there?
Space isn't "here or "there." Space defines "here" & "there." If there's no space, there is no "there," full stop.
Pegajace t1_jecxkph wrote
It's not expanding into anything. The expansion of the universe is not the motion of stuff through space, nor is it the motion of space through... super-space or something of that sort. It is fundamentally different from motion. It's a metric expansion, meaning that there's brand-new space coming into being everywhere, all the time, and the distances between objects simply get larger (at a rate that is getting faster as time goes on).
Pegajace t1_jecq816 wrote
Jehovah is the name of God in the Abrahamic religions (originally just Judaism, but later Christianity and then Islam, plus a variety of other smaller offshoots). The name is written as "יהוה" in the original Hebrew, and translated from Hebrew to English as "YHWH" or "Yahweh." "Jehovah" is what you get when the name takes a linguistic detour through Latin—much like "ישוע" ("Yeshua") is "Joshua" when translated directly to English, but becomes "Jesus" when it passes through Latin.
The name of the Jehovah's Witnesses refers to "witnessing" in the sense that you'd call a witness to testify in court, in that they're prepared to present the story of their personal experience as a reason for others to be convinced.
Pegajace t1_jcnwgbu wrote
Reply to Where do photons go if they've been emitted but are destined to never be absorbed, and would these photons traveling ad infinitum define the edge of the universe (even if space itself were still larger)? by mysteryofthefieryeye
>would these photons traveling ad infinitum define the edge of the universe
They would if the Big Bang had been an explosion at a specific point in space, but it wasn’t. There isn’t an expanding sphere of photons defining the outer edge of the universe because the universe did not start at a central point. The Big Bang was a rapid growth of spacetime that happened to space, not in space, and it happened everywhere simultaneously.
Pegajace t1_ja4apqv wrote
Reply to comment by ExtremeQuality1682 in Eli5 Help, please my brain hurts. If there is an expanding ring of light from the big bang, what is outside it? by ExtremeQuality1682
The speed of light is an upper limit on how fast matter, energy, and information can move through space. The expansion of space during the Big Bang (and afterwards at a much slower rate) is something fundamentally different from motion. It’s a “metric expansion,” which doesn’t require anything to move within space and is not limited by the speed of light. It’s not even measured in the same units as speed; speed is distance/time, whereas expansion is (distance/time)/distance, which oddly collapses down to just units of 1/time.
Pegajace t1_ja49i2z wrote
Reply to Eli5 Help, please my brain hurts. If there is an expanding ring of light from the big bang, what is outside it? by ExtremeQuality1682
>I'm just assuming that I'm correct in that there is an expanding ring of light, still expanding outward from the big bang
There isn’t, because the Big Bang wasn’t an explosion at a specific point in space casting matter into an empty void. It was a rapid growth of space itself that happened everywhere, and the closest thing to an afterglow (the “Cosmic Microwave Background”) can be seen from everywhere coming from every direction.
Pegajace t1_j6ifrl0 wrote
Reply to Why can we see exoplanets from distant galaxies, but not close-ups of planets outside the Kuiper Belt? by Worth-Masterpiece-98
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We cannot see any exoplanets from any galaxies outside our own. All the exoplanets we’ve found are in nearby areas of the Milky Way.
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When we do detect exoplanets, they tend to be large and orbiting close to their parent star. We cannot see them directly, but instead we observe their effect on the star, either by watching it wobble slightly as the two orbit their common center of mass, or by watching the star dim slightly as the planet passes in front. Neither of these methods is applicable to a planet in our own system orbiting far out from the Sun.
Pegajace t1_j2cd5zl wrote
Reply to comment by jayhovian in Why is Mitochondrial Eve dated to 150-170,000 years go? by jayhovian
The title of "Mitochondrial Eve" is defined as the most recent matrilineal common ancestor of all living humans. If we trace the ancestry of all living humans through their mother's side, all lineages pass through M.E. before they get to any generations further back, and once you're past M.E. all the lineages look identical.
Pegajace t1_iv3dvim wrote
Reply to comment by Nobpointe in Closest known black hole to Earth spotted by astronomers by lunarmoonr
This black hole presents no threat to us whatsoever. It's one hundred million times further away from Earth than the Sun is, and it's only got ten times the Sun's mass. Since the force of gravity decreases according to the square of the distance between objects, the effect it has on us is so tiny it can't be measured. For example, the dwarf planet Pluto pulls on the Earth with a gravitational force ~1,500 times greater than the black hole does, simply because Pluto is millions of times closer.
Even if the black hole was vacuuming us in at the speed of light (which, to be clear, it will not and cannot do), it's still 1,600 light-years away and would take 1,600 years for the Earth to get there—not exactly a problem for this generation.
Pegajace t1_iue38bi wrote
Reply to ELI5: If the James Webb telescope is able to look 13.6 billion light years away, why aren't we looking at the surface of planets to search for life? by NolosRTX
Planets outside our solar system are way, way, way, way, way, way, way too small and dim to be seen in any detail by any space telescope.
Stars shine with the light of nuclear fusion; planets can only reflect the light of their parent star, and the teeny tiny fraction of the light that they reflect is almost always drowned out by the star's light.
Nebulae can be dozens of light-years wide; the famous "Pillars of Creation" 7,000 light-years away are about four light-years in length, or almost forty trillion kilometers. The largest planets are only about 150,000 km in diameter, or 250 million times smaller than the Pillars of Creation.
Pegajace t1_iu8ia9j wrote
Reply to comment by dvmark in ELI5: What is a “Strawman” argument? by dclover27
That’s not what a strawman is. A strawman argument is a fallacy in which you deliberately misrepresent your debate opponent’s position, because your version of their position is easier to argue against than their actual position.
Pegajace t1_iu4q09z wrote
Reply to ELI5:A child causes a wagon to accelerate by pulling it with a horizontal force. newton's third law says that the wagon exerts an equal and opposite force on the child. how can the wagon accelerate? by Gbo_the_beast
Two equal and opposite forces exist, but they need not be applied to the same object. The wagon only experiences one force; that of the child pulling it. The opposite force is applied to the child, not to the wagon.
Pegajace t1_jeddkvd wrote
Reply to eli5: Who does the US owe almost 32 trillion dollars of debt too? If it’s the most powerful nation in the world, can’t it just get rid of it? by brybry0812
Most of the debt is owed to US citizens. If you've ever owned a US savings bond or similar, you've owned a portion of the US national debt.
>If it’s the most powerful nation in the world, can’t it just get rid of it?
The US borrowed money from people with the understanding that the money would be repaid in the future, plus interest. Announcing that they're not going to repay those debts would screw over everyone who was planning on being repaid, and would destroy the US' ability to borrow any more money in the future—because who would be dumb enough to loan their hard-earned cash to a government that can't be trusted to repay its debts?
On top of all that, there's a provision in the US Constitution that states that "the validity of the public debt [...] shall not be questioned," so the US couldn't legally default on its debt even if it wanted to.