Can we get information from outside of the Observable Universe by observing gravity's effect on stars that are on the edge of the Observable Universe? | AskScience Blog

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Saturday, May 4, 2019

Can we get information from outside of the Observable Universe by observing gravity's effect on stars that are on the edge of the Observable Universe?

Can we get information from outside of the Observable Universe by observing gravity's effect on stars that are on the edge of the Observable Universe?


Can we get information from outside of the Observable Universe by observing gravity's effect on stars that are on the edge of the Observable Universe?

Posted: 03 May 2019 10:36 PM PDT

For instance, could we take the expected movement of a star (that's near the edge of the observable universe) based on the stars around it, and compare that with its actual movement, and thus gain some knowledge about what lies beyond the edge?

If this is possible, wouldn't it violate the speed of information?

submitted by /u/BadassGhost
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Are there any trinary stars systems?

Posted: 03 May 2019 08:44 AM PDT

What determines the frequency of lightning in a storm?

Posted: 04 May 2019 04:36 AM PDT

I know this is probably a dumb question but some storms have lightning every two seconds while others can have a minute between strikes. I'm just curious as to why.

submitted by /u/cristianthechinch
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Can undersea cables undergo creep rupture?

Posted: 04 May 2019 04:28 AM PDT

The pressure down there must be quite high. Is there any proof that undersea cables have undergone creep?

submitted by /u/Sumage
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Why can't magnet bend light when light is made out of electromagnetic wave?

Posted: 04 May 2019 07:00 AM PDT

Light is made out of electric field and magnetic field. So why can't magnet interact with the magnetic field part of light?

submitted by /u/Prayut-Chan-o-cha
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How would matter behave in a negative temperature (negative Kelvin)? Is the phenomenon observable in nature?

Posted: 04 May 2019 02:43 AM PDT

How do astronomers differentiate gravitational waves originating from the merging of two black holes, a black hole and a neutron star or two neutron stars?

Posted: 03 May 2019 08:18 PM PDT

Question in the title. Was reading a post from r/space and they mentioned that the 4th gravitational wave originated from the merger of a black hole and a neutron star

submitted by /u/brandon92121
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How do computers generate random numbers for various probability density functions (PDFs)?

Posted: 03 May 2019 02:01 PM PDT

I'm more-or-less familiar with how uniform random numbers are generated, but what about other distributions, like normal random values? Can we take a uniformly-generated random value and then transform it to some arbitrary PDF, or does each PDF require a new method of hardware generation?

submitted by /u/jammin-john
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How good is a dog’s long term memory?

Posted: 03 May 2019 04:53 PM PDT

I have two dogs of my own. One of which we adopted from the humane society about 6 years ago. We estimated he was about 2 when we got him. He's not the smartest dog and he seems to forget things very easily or at least we think he does. I always wondered if he remembers his old home.

My other dog is just a puppy. We adopted her when she was 3 months old and lived with her litter and mom. She is now almost 7 months old and she has settled into our home very nicely. I wonder if she has any recollection of her other home, her siblings, or her mom. Would she remember them if she saw them again?

submitted by /u/bowlmyshoes
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Do microscopic life like protozoa die of old age?

Posted: 03 May 2019 01:51 PM PDT

How does light absorption/reflexion/transmission work on an atomic level?

Posted: 04 May 2019 02:59 AM PDT

Hello all!

What I'm trying to understand is this:

Why do materials have a specific wavelength of light which gets absorbed the most? The best explanation I could get is based on the Bohr atom model and states that the (material-specific) difference in energy required for an electron to jump to a higher orbit dictates the wavelength which is needed to stimulate those electrons. Meaning that materials with a high energy gradient between the orbits absorb light with a lower wavelength because it carries more energy. However, that doesn't sound right to me because that implies that a shorter than needed wavelength will always be absorbed since it carries more energy (E=hv) - which isn't always true (Just look at silver, it absorbs nearly 95% of the light at ~300 nm but less than 75% at ~260 nm).

For me, it looks like the electrons have something like a resonance frequency and respond much better to photons swinging in a similar band, but I couldn't find any source to back up my theory.

Reddit, help me out :)

submitted by /u/wictor1992
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Does the brain experience the REM cycle under general anesthesia?

Posted: 03 May 2019 03:55 PM PDT

How is zero gravity different from weightlessness?

Posted: 03 May 2019 10:06 PM PDT

Is there any difference? Are there any mathematical differences between the two scenarios?

submitted by /u/Shinigamii_
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How do normal cells around a cancer affect its ability to spread?

Posted: 03 May 2019 05:03 PM PDT

As title says.

How do normal cells in tumour microenvironment contribute to processes such as EMT?

submitted by /u/Spoonhands123
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Is there a minimum size for a star?

Posted: 03 May 2019 12:04 PM PDT

I know that the biggest stars can be many times the size of Earth's sun, but how small is the smallest star? Is there a minimum size required to make a star? If so, why?

submitted by /u/HerbalTeaParty
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Is a blue object blue because its excited electrons emit blue light, or because blue wavelengths are reflected?

Posted: 03 May 2019 06:05 PM PDT

We teach the kids in chemistry that excited electrons fall back to its ground state to emit a photon of a certain wavelength. The wavelength define its colour.

So let's say we are in a sealed room with a red light; I've always assumed we perceive the objects as red because the red light will excite the electrons in all objects to an energy level that results in the objects emitting a red photon back to us. While a blue light excite the electrons with a higher energy level, giving us blue light back. However, because of vibrational/rotational relaxation, the wavelength absorbed should have less energy when emitted back, resulting in a different colour.

There is also the reflection aspect, suggesting that it's not the emission of blue photons that makes objects blue, but just sheer reflection of the exact same wave (while red and green waves get absorbed).

Last example is when something is transparent in a certain colour. A regular glass window is transparent because it doesn't absorb anything in the VIS-spectrum. Consequentially a green window will absorb all of the red and blue light, letting only the green through, thus appearing green transparent. How is that different from a green opaque wall, that also absorbs red and blue light. Does a green window and a green wall treat the blue/red wavelengths the same (absorbing), while the green light is either reflected or just not absorbed. And what causes the difference?

submitted by /u/LupusX
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What happens when underground mammals die in their dens/tunnels?

Posted: 03 May 2019 11:15 AM PDT

Are they buried underground? Carried out from the den? I'm thinking of mainly foxes, rabbits, moles, badgers, and such.

Cheers!

submitted by /u/JPUF
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Why is better to set the sails against the wind to go faster sometimes?

Posted: 03 May 2019 11:20 AM PDT

I recently learned in physics about how every action has equal opposite reaction. On the topic of gravitational force the opposite is normal force. Where does this force originate from?

Posted: 03 May 2019 05:30 PM PDT

Is there a limit on how massive a blackhole can be?

Posted: 03 May 2019 02:56 PM PDT

Are we using energy when we think? If so how much?

Posted: 02 May 2019 10:10 PM PDT

I was in a lecture the other day after a poor night's sleep and came across a pretty basic math problem that I could usually do in my head. I started working it out and then 3 seconds later decided I couldn't be bothered, which made me wonder, do we use up energy when we think hard enough just like we use energy when doing physical work? Why else would I be so opposed to working a problem in my head?

submitted by /u/rapsohelpme
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