What are the properties of an ion engine exhaust? Is it warm? Is the engine loud? What would happen to stuff that gets in the way of the exhaust? |
- What are the properties of an ion engine exhaust? Is it warm? Is the engine loud? What would happen to stuff that gets in the way of the exhaust?
- The majority of drugs that work in mouse models are not successful in humans. Is the inverse also true, are there drugs that do not work in mouse models but do work in humans?
- Is a star’s luminosity dependant on ‘Big G’?
- Does a black hole grow as it absorbs more mass?
- If two babies never exposed to language grew up alone on a deserted island, would they ever develop any form of language?
- Why is boron classified as a metal and a non-metal on the periodic table?
- If 300 million years ago oxygen levels were 35%, why are they lower now?
- Can fabric and insulation (heat) be made from non-carbon-based materials?
- Is there a molecular or structural difference between cancer and metastatic cancer?
- Escape velocity of Earth is 11.186 km/s. Does rockets we launch goes upward with this speed?
- If someone resembles one parent in outward appearance does this mean they resemble that one parent "internally" e.g. propensity to heart disease, mental ability, propensity to breast cancer?
- Does previous acclimatization make future acclimatization easier? (X/mountaineering)
- Why do butterflies sometimes land on things and open/close their wings really slowly?
- Why are cro magnon not considered a subspecies but homo sapiens idaltu is when the anatomy of cro magnon seems to be more different to homo sapiens sapiens compared to idaltu?
- How does it make sense to talk about the volume of a given gas (as an inherent property of it), when gases always occupy the volume of the recipient they are in, and thus have variable volume?
- Is there much or any variation in size between different people's eyeballs?
- What is the proportion of the size of blackhole's event horizon compared to the volume of mass that created it?
- If light radiating from a star expands like a sphere in all directions, how is it that after many light years of expansion when that light finally reaches Earth such a small area of that sphere still seems to contain enough photons to blanket every square millimeter of our planet?
- Whats the difference between Centrifugal and Centripetal force?
- Is it possible to have planets orbiting a star in significantly different planes, similar to the Rutherford atomic model but with the star as the nucleus?
- How did laughing and the concept of humour evolve?
| Posted: 25 Nov 2018 05:06 AM PST I have seen ion engines only in games or still images, and I am curious about the effects the exhaust has on stuff. Since it's electrically accelerated propellant, and such a low amount, it feels like it shouldn't affect a hand/other stuff in the exhaust, but I might be completely wrong. [link] [comments]  |
| Posted: 25 Nov 2018 07:21 AM PST Venn diagram version of question https://imgur.com/etQoR0N [link] [comments]  |
| Is a star’s luminosity dependant on ‘Big G’? Posted: 25 Nov 2018 04:13 AM PST I was reading 'Astro for people in a hurry' by deGrasse Tyson and he stated that 'if you do the math you can determine that a star's luminosity is steeply dependant on 'big G'." I don't remember any such relation - nor can I find it online with a very quick browse. I imagine he is right, since it's in a book, so where am I wrong? Edit: dependent* [link] [comments]  |
| Does a black hole grow as it absorbs more mass? Posted: 25 Nov 2018 05:00 AM PST |
| Posted: 24 Nov 2018 11:25 AM PST Just wondering about how natural language is for humans. Would they be silent? Grunt at each other? Or would they naturally form a language full of nouns and verbs? [link] [comments]  |
| Why is boron classified as a metal and a non-metal on the periodic table? Posted: 25 Nov 2018 07:18 AM PST |
| If 300 million years ago oxygen levels were 35%, why are they lower now? Posted: 25 Nov 2018 12:53 AM PST It is thought that 300 million years ago the oxygen concentration on Earth may have been as high as 35%. What I don't understand is why oxygen levels in the atmosphere aren't 35% now given the following logic: Oxygen in the atmosphere is almost entirely a result of organisms doing oxygenic photosynthesis. Photosynthetic organisms split water yielding O2 (which is released to the atmosphere and thus increasing atmospheric O2 concentrations) and the reducing equivalents are used to reduce CO2 into sugars and other organic molecules. So for O2 levels to have been 35% in the atmosphere, a full 66% higher than they are now, then there must have also been 66% more reduced things somewhere else. So my question is where was that extra 66% stored back then, and why isn't it in circulation now? I've only seen casual explanations for why oxygen levels were higher in the past, and nothing about the discrepancy of high O2 levels vs "reduced things" levels. I'm hoping someone knows of a rigorous article on the subject. I can postulate 3 options but I'm not really in love with any of them: Option 1: There could have been 66% more living things 300 mya. But that requires 66% more CO2 to have been reduced into organic molecules in living things. Where did that carbon go over the last 300 mya? For the hypothesis to work, as the quantity of life decreased from it's hypothetical peak 300 mya to now, the carbon would need to be released as CO2. But CO2 levels are thought to be lower now than they were 300 mya, even with the increased fossil fuel use in the last 200 years. Simply burying the life after it died, allowing it to ultimately become coal and oil, doesn't explain the discrepancy. Coal and oil still have the reducing equivalents in them, hence why we can burn them into CO2. So for this hypothesis to be true, some combination of forces was net emitting lots of CO2 then, and net removing CO2 out of the atmosphere now. Some combination of volcanoes vs rock weathering could explain this, but 300 mya is only about 6.6% the age of the Earth. Are these forces really so dynamic as to produce this result in a relatively short period? Option 2: There was some slowly oxidizing material in the Earths crust that took an extra couple hundred million years to oxidize after the Great Oxygenation Event had oxidized everything else in the crust. In this theory the crust of the Earth was removing O2 out of the atmosphere more slowly than it was being produced for a short while, allowing oxygen to build up to 35%, above the equilibrium amount. Eventually photosynthesis became limited by whatever it's limited by and the O2 equilibrium amount of around 21% was reached, as it is today. But what material would be capable of this slow oxidation that would need to be quite abundant in the crust? Option 3: After the Great Oxygenation Event the oxygen levels on Earth have been relatively constant around 21%, and simply our ability to measure it accurately is difficult because, you know, 300 million years have elapsed. Since I don't fully understand how the estimates are made I have no ability to really asses their validity. Therefore I'm inclined to trust the people who spend all their time arguing with each other about the estimates. Edited for clarity [link] [comments]  |
| Can fabric and insulation (heat) be made from non-carbon-based materials? Posted: 25 Nov 2018 06:21 AM PST I'm working on a novel, and I'm wondering if there is a substitute for carbon-based materials to make clothes and heat insulation for houses. If so, what processes can be used to produce the carbon-free clothes and insulation? [link] [comments]  |
| Is there a molecular or structural difference between cancer and metastatic cancer? Posted: 25 Nov 2018 06:01 AM PST Apart from the localization is there a molecular or structural difference between for example HER2-negative ER-positive breast cancer and metastatic cancer of the same type? [link] [comments]  |
| Escape velocity of Earth is 11.186 km/s. Does rockets we launch goes upward with this speed? Posted: 24 Nov 2018 10:30 PM PST |
| Posted: 24 Nov 2018 09:46 AM PST So if you for example *look* like your dad do you have genetic similarities in the same proportions on things other than outward appearance. [link] [comments]  |
| Does previous acclimatization make future acclimatization easier? (X/mountaineering) Posted: 25 Nov 2018 01:43 AM PST I was born and raised in a higher altitude/cold climate (Canadian Rockies) but have since moved to sea level in (warmer) Europe. I intend to climb Mont Blanc (French Alps) in a year or so and was wondering if it will be easier for me to acclimatize due to living at a higher altitude most of my life, or if the time spent at sea level will completely reset my system. [link] [comments]  |
| Why do butterflies sometimes land on things and open/close their wings really slowly? Posted: 24 Nov 2018 06:20 AM PST |
| Posted: 25 Nov 2018 12:51 AM PST |
| Posted: 24 Nov 2018 12:31 PM PST It might be too long since I took high-school level physics and I forgot, but declarations like "gas X has a volume of Y liters at standard temperature and pressure" don't currently make much sense to me because gases will expand to occupy the volume of whatever container they're put in. Thanks for the clarification. [link] [comments]  |
| Is there much or any variation in size between different people's eyeballs? Posted: 24 Nov 2018 03:18 PM PST |
| Posted: 24 Nov 2018 07:18 PM PST As in, how much bigger/smaller is a black hole than the star that it was born from (accounting for the lost mass during the super nova, if possible) [link] [comments]  |
| Posted: 24 Nov 2018 08:56 AM PST |
| Whats the difference between Centrifugal and Centripetal force? Posted: 24 Nov 2018 10:20 AM PST |
| Posted: 24 Nov 2018 11:14 AM PST |
| How did laughing and the concept of humour evolve? Posted: 24 Nov 2018 08:29 AM PST |
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