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Thursday, January 5, 2017

AskScience AMA Series: I am Seth Shostak, senior astronomer at the SETI institute. Ask Me Anything!

AskScience AMA Series: I am Seth Shostak, senior astronomer at the SETI institute. Ask Me Anything!

AskScience AMA Series: I am Seth Shostak, senior astronomer at the SETI institute. Ask Me Anything!

Posted: 05 Jan 2017 05:00 AM PST

I'm Seth Shostak, Senior Astronomer at the SETI Institute, and I've bet anyone a cup of coffee that we'll find convincing proof that the aliens are out there within two decades.

I'm involved in the modern search for intelligent life in the cosmos. I have degrees in physics and astronomy, and has written four books and enough articles to impress my mom. I am also the host of the weekly radio program, "Big Picture Science."

Here is a recent article I wrote for NBC MACH Are Humans the Real Ancient Aliens?. Ask me anything!

Seth will be around from 12-2 PM ET (16-18 UT) to answer your questions.

submitted by /u/AskScienceModerator
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What is the average distance between Trojan asteroids at Jupiter's L4 and L5?

Posted: 04 Jan 2017 11:24 PM PST

Just read NASA's press release about Lucy and Psyche, the former of which will explore six of Jupiter's Trojan asteroids. Got curious as to how densely packed these swarms of asteroids are at L4 and L5.

For the curious: https://www.nasa.gov/press-release/nasa-selects-two-missions-to-explore-the-early-solar-system/

submitted by /u/orbitalengineer
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How does a charged particle not lose all of its energy even though it constantly generates an electromagnetic field?

Posted: 04 Jan 2017 09:28 PM PST

If a charged particle creates an electromagnetic field, doesn't the information in that field have to be carried by photons to "sense" whether or not there exists another charged particle in the field? As far as I know, information can't be shared or transferred without using energy, and charged particles share information using photons.

However if all charged particles are constantly giving off photons to generate this field, how is it that they don't lose all their energy?

I'm sure there's something I'm missing, and I would really appreciate some clarity.

submitted by /u/absheckler
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Why do drugs that increase gaba levels prevent and treat anxiety and panic?

Posted: 05 Jan 2017 06:32 AM PST

Some anxiolytic medications work by increasing gaba levels, but why does increasing gaba levels prevent anxiety?

I know gaba is an inhibitory neurotransmitter but why does that lead to less anxiety? What parts of the brain become overactive in anxiety that get quelled with gaba medications?

submitted by /u/Five_Decades
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Is it possible to accidentally create a black hole in one of those particle accelerators? If so, how quickly would we be sucked into it if was stable?

Posted: 04 Jan 2017 07:09 PM PST

Could strong radio wave bursts be used for space ship propulsion?

Posted: 05 Jan 2017 03:48 AM PST

Why are wind turbines the height they are?

Posted: 05 Jan 2017 02:05 AM PST

So I understand the general purpose of wind turbines. Generate wind power for energy and electricity.

According to websites, the height of an industrial wind turbine is 212 ft. and the blade is 116 ft.

Why are they this specific height and length of the blade? Is this the ideal height and length, or is there more to it? Wouldn't you be able to generate more wind power if you increase the height of the tower and the blades by 30%?

What would be the downside if you increase the size of the wind turbines?

submitted by /u/maxxxl
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Is there a maximum "size" limit of the universe?

Posted: 05 Jan 2017 04:26 AM PST

If Neutron stars and Black Holes are incredibly dense then is there a maximum size vs mass of objects in the universe before they collapse?

submitted by /u/I_Zeig_I
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If I have sufficient upfront capital, can I turn a series of marginally negative expectation bets into a process with an overall positive expectation process by using my deep pockets to chase my losses?

Posted: 04 Jan 2017 12:04 PM PST

As far as I know, in roulette, you can bet on red or black. If you guess correctly, you double your money. The bet pays 1:1 but is negative expectation bet because the numbers in roulette are not 50% black and 50% red. Rather, there's one or two green (0 and 00) spots. Meaning that you're going to be right just under half the time and since you're only doubling your money when you win, the bet has a negative expectation.

Variance is obviously high, but on a long enough time line, you will go broke.

But let's say you had a huge starting capital. Like $2m. And you decided you wanted to live in the hotel above the casino and live like on $1,000 per day for the rest of your days. $2m will only get you that life for 5 years. Not sufficient. You're young.

You decide to try to start each day by going down to the roulette table and putting $1,000 on black.

If you win (~50% of the time), you're up 1k and you're done gambling for the day and you go about your life.

If you lose (~50%), you bet $2,000 on black. If you win, you're up 1k and you're done gambling for the day and you go about your life.

...

If you lose six times in a row (~2%), you bet $64,000. If you win, you're up 1k and you're done gambling for the day and you go about your life.

Obviously there will always be a non-zero that the wheel will come up red X times in a row and you will go broke. But what's X? What's the chance that you can live 80 years on this ridiculous gambit? Is there a way, with a huge capital and chasing losses, to take this fundamentally negative expectation bet and alchemy something that is most likely to turn a marginally profit?

Assume for this query that (a) you spend the full $1,000 every day no more or less and (b) there's no real-world issues of casinos refusing your patronage, maximum bet sizes, taxes, inflation, etc...

submitted by /u/kneeco28
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What makes opioids so addictive over other forms of painkillers?

Posted: 04 Jan 2017 02:02 PM PST

How are membrane proteins, e.g. receptors, ion channels, oriented in the correct direction? Has it ever been observed for them to be "upside down" and what might cause this if so?

Posted: 04 Jan 2017 12:51 PM PST

Was thinking about the N- and C- terminals of GPCRs and got to wondering how they actually get oriented so the ligand binding domain is faced to the outside and the portion that interacts with G proteins, arrestins etc is faced towards the cytosol.

submitted by /u/ONeill_Two_Ls
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Why does the far side of the moon have so few lunar maria?

Posted: 04 Jan 2017 12:31 PM PST

If the moon is differentiated, then why is there so much assymetry in the geological features in the two sides? Is the far side's crust somehow thicker?

submitted by /u/ApertureMesa
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[Astrophysics] Is an Elliptical Orbit with an equal pericenter Possible? (Picture Example)

Posted: 04 Jan 2017 02:01 PM PST

Did some preliminary googling (unsuccessfully), but am wondering if an orbit like this is possible Where "r1==r2", and so is "r3==r4" - and consequently, you have two identical Apoapsis, and two identical Periapsis.

Most orbits that I've seen in diagrams are either circular or elliptical with a different r1 and r2.

The context of this question is mainly about a large body, small body (Earth, Moon etc) orbit, but any extra discussion about achieving a similar orbit with spacecraft or binary orbits(?) is cool too.

Thanks in advance for any help with this.

submitted by /u/Drumsmasher17
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Why are horizontal stabilizers on planes made to generate "inverse lift" - in other words, push the tail down?

Posted: 04 Jan 2017 05:28 PM PST

For your typical plane, in normal level flight the wings create the positive lift and the horizontal stabilizers (tail surfaces) create negative lift. Why is it needed?

submitted by /u/SurfingDuude
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What are physicists' best ideas for solving the proton radius puzzle?

Posted: 04 Jan 2017 07:48 AM PST

When you measure the proton radius by firing electrons at it, you get a different value than if by firing muons. Currently, this is unexplained by the standard model and there is no widely accepted explanation as to why this should happen. Despite this, what believable interpretations have physicists postulated since?

submitted by /u/Dkondr
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Are there any Anglo groups still living tribally anywhere in the world today?

Posted: 04 Jan 2017 09:14 AM PST

Can a light intermittently blink on and off so quickly that we see it as always off?

Posted: 04 Jan 2017 07:42 AM PST
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Wednesday, January 4, 2017

Why do freshwater fish tend to have dull colors while tropical fish tend to have bright colors?

Why do freshwater fish tend to have dull colors while tropical fish tend to have bright colors?

Why do freshwater fish tend to have dull colors while tropical fish tend to have bright colors?

Posted: 03 Jan 2017 05:06 PM PST

Is orbital energy lost through gravitational waves in all orbits, or only elliptical ortbits? Would a perfectly circular orbit create gravitational waves?

Posted: 04 Jan 2017 06:44 AM PST

The Coulomb force is inversely proportional to the square of the distance b/w charges. In the nucleus of an atom, with two protons next to each other, the repulsive force will be infinite as the distance between them would be 0. Is the 'Strong Force' responsible for holding them together, infinite?

Posted: 04 Jan 2017 12:36 AM PST

Despite the sun being nearly 100 million miles further away than the moon, I wouldn't be able to tell you which one is closer without already knowing. What is the maximum distance that variations in depth can be perceived at, and why?

Posted: 03 Jan 2017 07:51 PM PST

Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology

Posted: 04 Jan 2017 07:05 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Economics, Political Science, Linguistics, Anthropology

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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Why are FM radio frequencies always listed with odd decimals (.1, .3, .5 etc instead of .2, .4, .6)?

Posted: 03 Jan 2017 07:26 PM PST

Are forests and jungles growing more rapidly now that there is an increase of CO2 in the air?

Posted: 03 Jan 2017 05:22 PM PST

Why does water flow out in a twister when I drain the bathtub?

Posted: 03 Jan 2017 06:04 PM PST

Did early humans have any predators?

Posted: 03 Jan 2017 05:51 PM PST

Is it possible that emotions were developed from a consistent response to similar situations?

Posted: 04 Jan 2017 06:53 AM PST

I would think that emotions didn't always exist throughout life and had to be developed. Would being exposed to the same or similar scenario eventually lead to developing that emotion?

Examples:

Seeing a potential mate could lead to Love

Having food stolen could lead to Anger

submitted by /u/jrsooner
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What is the relationship between a photon's spin and polarization?

Posted: 03 Jan 2017 11:10 PM PST

I've been told that a photon's spin vector is ultimately measuring the same thing as the electric and magnetic ripples it creates but I can't figure out the mathematical relationship.

Spin is measured in units of angular momentum while electric and magnetic potential have their own units. Is there a simple equation that describes this relationship?

submitted by /u/chunkylubber54
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Since OCPs are designed to stop ovulation in fertile women - does this mean that women who take OCPs can get pregnant at more advanced ages?

Posted: 03 Jan 2017 04:09 PM PST

This may be a stupid question, but since OCPs are supposed to stop ovulation, and there are only a certain amount of eggs a woman carries at birth, does stopping ovulation for (let's say as an example) five years from age 20-25, give that woman 5 years of extra eggs compared to a woman who did not take OCPs?

Or do these eggs still get damaged during the time the woman is on birth control?

submitted by /u/NYCalifornian
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Did ancient peoples just have rampant oral disease (gingivitis, plaque, tartar, cavities) or was there a diet good for oral health?

Posted: 03 Jan 2017 02:52 PM PST

It doesn't make much sense to me that oral disease is so common we have to brush and floss our teeth with fluoride daily. I feel like something's wrong, probably our diet.

So is there a diet where you wouldn't get these common oral diseases? Or was there a technique ancient peoples used to clean their gums? Did they have floss?

If they did have terribly unhealthy mouths, why wasn't this naturally selected against either by disease or sexual selection?

submitted by /u/mwarg
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Why is there thunder and lightning during rainstorms, but not during snowstorms?

Posted: 03 Jan 2017 02:48 PM PST

Why does wire through a coil not short out and turn into one giant conductor?

Posted: 03 Jan 2017 08:21 PM PST

For example, in an electromagnet, the field all go through the core but why does electrons travel through the wire instead of all over since they are all touching and conducting?

submitted by /u/allnamesfckintaken
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If mass distorts space, can space tear? i.e., Does space have a distortion limit?

Posted: 03 Jan 2017 10:57 AM PST

What specifically stops viruses or bacteria such as the Acquired Immune Deficiency Syndrome from being passed on through saliva? How does this differ from sexual fluid?

Posted: 03 Jan 2017 03:59 PM PST

I thought there is a direct connection between saliva and your bloodstream. Isn't that why taking medication per os, buccal or sublingual work?

submitted by /u/BiozBug
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Why does it take more delta V to hit the sun than it does to leave the solar system?

Posted: 03 Jan 2017 09:25 AM PST

There was a discussion on Reddit about disposing nuclear waste and someone mentioned it would be cheaper to have it leave the atmosphere than to crash it into the sun.

Basically people were saying that if you are already going at the orbital speed of Earth, it doesn't take that much extra to accelerate to the escape velocity of the solar system.

For some reason though, everyone was assuming that you would have to completely lose all of your orbital speed before falling into the sun.

Why can't you just subtract a bit of your orbital speed and put yourself in a decaying orbit? It seems to me that people are calculating the bare minimum to leave the Solar System and comparing it to the speedy way to get to the sun.

submitted by /u/nagurski03
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Are there any animals that get smaller as a normal part of their life cycle?

Posted: 03 Jan 2017 07:12 AM PST

It seems that at any given moment in a creatures life, it either grows bigger or has stopped growing. With the exception of insects that go through a metamorphosis, are there any animals that are known to "grow smaller" for whatever part of their life?

submitted by /u/grape_tectonics
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Why are people advised not to drink alcohol when taking antibiotics?

Posted: 03 Jan 2017 09:50 AM PST

Can the speed of particles in a plasma be modelled by a Maxwell-Boltzmann distribution? What about a liquid? Is the Maxwell-Boltzmann distribution only for gasses?

Posted: 03 Jan 2017 01:27 PM PST

How big does a sphere need to be for its surface to be considered "flat" from a human perspective?

Posted: 03 Jan 2017 02:23 PM PST

Apologies for bad English.

Let's say you get a ball. You obviously perceive it as a round object. But if you increase it's size and keep increasing it, eventually you won't realize it's round, just like people in ancient times (except the FLat Earth Society members of course) thought the Earth was flat. Is there a known size where this happens? If not, can you give a rough estimate? Thanks for the answers.

submitted by /u/RegularSpaceJoe
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Tuesday, January 3, 2017

Is there a reason all the planets orbit the sun in approximately the same plane and direction?

Is there a reason all the planets orbit the sun in approximately the same plane and direction?

Is there a reason all the planets orbit the sun in approximately the same plane and direction?

Posted: 03 Jan 2017 03:52 AM PST

Is it more energy efficient to leave the heater on low when nobody is home, or to heat it up from cold when you get back?

Posted: 03 Jan 2017 01:50 AM PST

So this morning as I was the first to walk back into my freezing office after the holiday, I was reminded of an argument I used to have with my roommate when I lived in a drafty old house in upstate New York. We would both leave the house for one to two weeks every Christmas, turning the thermostat down to something like 5C while we were away, and when we returned we would have to run the furnace full blast for about three days to get the house up to 22C again. I would always suggest that it would be better leave the thermostat on something in the middle while were gone, like 15C, but he thought it was a waste of energy. I argued that it took just as much energy to run the furnace continually for those three days when we returned than it did to maintain a modest temperature while we were away. In reality, I have no idea, but I just hated those three days of feeling cold.

Obviously, this depends on lots of factors, like how cold it is outside and how long we are gone. But in general, ignoring issues like pipes freezing, does it use more energy to maintain a moderate temperature for a long time and then heat it up for a short time, or to let something cool way down and then heat it up all the way?

submitted by /u/NerdWithoutACause
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To travel back in time wouldn't you need to increase the entropy of the entire universe at every point?

Posted: 03 Jan 2017 05:27 AM PST

And since info is lost in black holes and thus cannot be "rewound" to a prior state, doesn't that disprove the possibility of reverse time travel?

submitted by /u/eaglessoar
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If you lay or sit in a position that causes a limb to "go to sleep," would you then be able to amputate that limb painlessly?

Posted: 02 Jan 2017 11:57 AM PST

If Earth had a huge equatorial ocean like it did in the past, would it be possible we'd observe persistent hurricanes lasting months or even years, like a mini-version of Jupiter's great red spot?

Posted: 02 Jan 2017 01:24 PM PST

What about rocky planets larger than Earth or planets completely covered in ocean? Might permanent or semi-permanent weather-features exist there, or are such storms a rarity even among gas giants?

submitted by /u/Taman_Should
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Do engineers at CERN have to repair the Large Hadron Collider after every "explosion" that happens? [Physics]

Posted: 03 Jan 2017 02:20 AM PST

Tried googling it but a bunch of old 2012 articles came up focusing on the "black hole" thing. But, are the explosions large enough to cause that type of damage? I get that they're not "explosions" like a bomb, but they're still particles slamming into each other at nearly the speed of light, so I would imagine some thinking could be damaged.

submitted by /u/turtlecam_son
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How much of the world's air is trapped in bubble wrap?

Posted: 02 Jan 2017 07:28 PM PST

How do oxygen meters measure oxygen level externally through the thumb or index finger?

Posted: 02 Jan 2017 08:23 PM PST

I was recently in the hospital for a respiratory illness and the nurse measured my oxygen level with a thing that clipped to my index finger. How does it work? Does it have to do with pulse?

submitted by /u/potatopigs
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Why is there only one Hubble Ultra Deep Field image?

Posted: 02 Jan 2017 03:03 PM PST

You always see that same image floating around. The Hubble space telescope was pointed in one direction for 4 months or so, gathering a bunch of data before eventually generating that beautiful image of the distant galaxies. That image blows my mind every time. What makes it even crazier is that the field of vision of the telescope to generate that image was pointed at a super small portion of the sky (I've heard it described as being the same relative size as a tennis ball on the other side of a football field)

BASICALLY, my question: Why haven't astronomers taken more pictures in other directions in the sky, to generate even more incredible images of all sorts of different galaxies, stars, and colors? It seems like we cling on this single image like it's the only one we are able to generate.

submitted by /u/yenzy
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Why did we evolve the inability to eat raw meat safely?

Posted: 02 Jan 2017 04:24 PM PST

Assuming that we evolve beneficial traits over time and that our ancestors were likely able to eat raw meat. Why would we evolve to not be able to eat raw meat? Surely that's disadvantageous?

submitted by /u/TRFKTA
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Is the water at the bottom of the Mariana Trench just as salty as the water at the surface?

Posted: 02 Jan 2017 03:31 PM PST

Why no matter how bad a relationship was do our brains always focus on the good memories rather than the bad after a breakup?

Posted: 02 Jan 2017 08:30 PM PST

[physics] Why does the texture of icecream change when melted and refrozen?

Posted: 02 Jan 2017 09:44 PM PST

I was eating some sorbet (not icecream I know but the same thing happens to icecream), and I made the mistake of taking a post-sorbet nap without putting it back. It melted, I refroze it, and now i'm eating it again to find that the texture is no longer soft, it's like a frozen slushie now, full of hard icy flakes. Why is that?

submitted by /u/Danyerue
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How did early computers display characters in languages where the letters are more complicated than English-type (and languages that use the same characters)?

Posted: 02 Jan 2017 09:28 PM PST

Like with Japanese characters, was it difficult to fit all the little markings of each character? Even with English characters in very basic fonts, it seems like there is little wiggle room and that the characters had to be carefully designed (and yes I know the characters are not specific to English, I just don't know what to call it). Does anyone have any examples of how it was done it languages with more complex letters/characters?

submitted by /u/muzwim
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Why does the moon appear to tilt on its axis over the course of its transit across the sky each night?

Posted: 02 Jan 2017 09:23 PM PST

This is a question that has plagued me since I was a teenager and I could never find someone to answer or knew how to phrase it for an online search.

In the instance of a quarter moon for example, when I first see it it may appear to be standing up "vertically" like I could draw a straight line through the terminator and down to the horizon. Then a few hours later that same terminator might appear to be at an angle.

What's going on here? I know the moon isnt tilted. Is the shadow what's actually moving and not the moon itself?

Thanks!

submitted by /u/foxwox
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What is an estimate of the population that the earth could sustain?

Posted: 02 Jan 2017 01:47 PM PST

How do laboratories make chemicals?

Posted: 02 Jan 2017 07:24 PM PST

Not really sure how to explain what I mean, but here goes. How do scientists make chemicals and stuff themselves? For example, when a lab is working on developing a new painkiller, or their own version of a hormone or chemical naturally made in the human body, how do they make it? How do they make something with a specific chemical structure and composition? I hear about medications and chemicals being developed all the time, but I don't have any idea how the actual chemical gets created.

submitted by /u/mimib14
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Why do we produce so much mucus when we are sick?

Posted: 02 Jan 2017 02:12 PM PST

If mosquitoes can transmit Ebola and other viruses, can they also transit HIV?

Posted: 02 Jan 2017 04:04 PM PST

After the Big Bang the Universe cooled down and eventually formed planets, stars, etc. How is this not a decrease in entropy?

Posted: 02 Jan 2017 02:50 PM PST

Or is the entire universe considered an isolated system so there was a significant increase elsewhere?

submitted by /u/Ademptis
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Is raising bison better for the environment than raising cows?

Posted: 02 Jan 2017 11:02 AM PST

I've read from a few less-than-trustworthy sources that bison farming is more environmentally friendly than farming cows for beef. I've tried searching around online, but I haven't found any sources that really clear this up. What I want to know is:

  • Pound for pound, as the industry currently stands, is bison more environmentally friendly than beef?
  • If the US meat industry were to tone down its beef farming and increase production of bison meat, creating the need for larger bison farming enterprises, would bison still have an environmental advantage over beef?
  • Are fish and poultry more environmentally friendly than bison regardless?
submitted by /u/hrbuchanan
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