A Collection of Possibilities

awandererswondering: carbonstuff: Let’s talk about the dark...

Fri, 24 May 2013 20:01:11 -0400

carbonstuff:

Let’s talk about the dark night. ~~Yes this post is about Batman.~~

Our common assumption is that the night sky is supposed to be dark with only few dots of light.

But then, aren’t there supposed to billions upon billions of stars in the night sky emitting light. Yes, they are very far away, but, there is nothing stopping (like air or glass) the light from reaching us. So, shouldn’t all those stars make the night sky (very) bright and not dark ?

This is actually called Olbers’ Paradox.

Let’s look at the problem in another way. We can divide the universe into a series of concentric shells, being 5 light years thick. Thus, a certain number of stars will be in the shell 1,00,000 to 1,00,005 light years away. If the universe is homogeneous at a large scale (i.e., static), then there would be four times as many stars in a second shell between 2,00,000 to 2,00,005 light years away.

But, the second shell is twice as far away, so each star in it would appear four times dimmer than the first shell (intensity is inversely proportional to the square of distance). Thus the total light received from the second shell is the same as the total light received from the first shell.

Thus, the argument is that if the universe were static and filled infinitely with stars, the night sky should be much brighter than it is now.

I think you guessed the loop hole here. I said if the universe were static, which it clearly isn’t.

The Big Bang explains this paradox by saying that the universe started at a point, and expanded from that point. Thus, it is not static.

We know that the expansion is accelerating. So, two things happen.

One is that, those stars in the night sky are moving away from us and the distance between them and us increases. This increase the time for to see them and eventually it takes millions of years for the light from those stars to reach us.

Second, which is the more important reason, is that these starts get redshifted away. Redshifting is when the wavelength of an object moving away from us goes towards the red side of the spectrum and eventually, it goes into the infra red, which we cannot see. It is like we listen to a honking truck passing by at great speed. As it moves away from us, the the sound becomes softer and softer and eventually it is inaudible.

So, because of these reasons, we never get to experience the real night sky light. But, it may be a good thing, as otherwise our eyes would be blinded by the light !

Image via Wikimedia Commons

THANK YOU.

A brilliantly worded explanation for an interesting concept.

older-aang: baw-bee: sophieonpage: thegoddamazon: I present...

Fri, 24 May 2013 00:13:02 -0400

older-aang:

baw-bee:

sophieonpage:

thegoddamazon:

I present the most badass gifset on Tumblr.

Legitimately turned on by this

This is the best thing.

Why this cartoon is the best cartoon.

ilovecharts: Interactive Guide For Comparing the Speeds of...

Thu, 23 May 2013 23:32:23 -0400

ilovecharts:

Interactive Guide For Comparing the Speeds of Famed Sci-Fi Ships

itemfinder: unimodus: fuckyeahstartrektos: Useful...

Thu, 23 May 2013 23:24:31 -0400

itemfinder:

unimodus:

fuckyeahstartrektos:

Useful information

good lord can fleet admirals even lift their arms?

“It’s just the standard amount of gold braid”

Photo

Thu, 23 May 2013 23:14:54 -0400

lindsaur-gor: There needs to be a code word or something that means “my brain is fighting me every...

Thu, 23 May 2013 20:01:38 -0400

lindsaur-gor:

There needs to be a code word or something that means “my brain is fighting me every step of the way today and I feel like I’m going to vibrate out of my skin, so I need you to forgive everything and go slowly and speak softly and lower your expectations.” And then we could all just be like, “I know I said we could go to a movie tonight but… tangerines.” And the other person would nod and squeeze your elbow or rub your head and you wouldn’t feel like a failure.

Photo

Thu, 23 May 2013 03:39:53 -0400

Photo

Wed, 22 May 2013 20:01:23 -0400

verdantmug: Some favorite sci-fi rides poster / shirt

Wed, 22 May 2013 00:27:21 -0400

verdantmug:

Some favorite sci-fi rides

poster / shirt

the-fandoms-are-cool: all-misty-eyed: The TARDIS as seen on...

Tue, 21 May 2013 23:32:38 -0400

the-fandoms-are-cool:

all-misty-eyed:

The TARDIS as seen on the first episode of Doctor Who, 1963.

New rule…first ever fucking TARDIS Always fucking reblog

ALWAYS reblog the moment of the Broken Chameleon Circuit

catfoxwolf: Keep good company.

Tue, 21 May 2013 20:01:33 -0400

catfoxwolf:

Keep good company.

adrfabrika: [ pen + after ] www.adrfabrika.info

Mon, 20 May 2013 20:01:20 -0400

adrfabrika:

[ pen + after ] www.adrfabrika.info

spaceplasma: A run on Fusor V showing X-rays effecting the...

Sun, 19 May 2013 17:51:05 -0400

spaceplasma:

A run on Fusor V showing X-rays effecting the CCD

Fusor V: X-ray and Neutron Emissions

The fusor, is an apparatus designed to create nuclear fusion. Unlike most controlled fusion systems, which slowly heat a magnetically confined plasma, the fusor injects high energy ions directly into a reaction chamber, thereby avoiding a considerable amount of complexity. The approach is known as inertial electrostatic confinement (IEC).

Regardless of its possible use as an energy source, the fusor has already been demonstrated as a viable neutron source. Fluxes are not as high as can be obtained from nuclear reactor or particle accelerator sources, but are sufficient for many uses.

Watch the video

Credit: Robert Tubbs

alexanderpf: Volet Végétal by Barreau & Charbonne...

Sun, 19 May 2013 03:21:08 -0400

alexanderpf:

Volet Végétal by Barreau & Charbonne via mindyourgarden

Horizontal position to enlarge a green view on the city land and get more ornamental stand for plant. Vertical to create a shutter of light, a filter for green air and also for an easy garden upkeeping.

thescienceofreality: This Week in Science - May 13 - 19,...

Sun, 19 May 2013 02:58:48 -0400

thescienceofreality:

This Week in Science - May 13 - 19, 2013:

Magnetar at black hole here.

Cloned human stem cells here.

Cell calculators here.

Music matched to color here.

Scientists agreeing on climate change here.

Remote-piloted plane here.

Earth’s core here.

Bright lunar explosion here.

American asteroid sampling here.

Hofstadter butterfly effect here.

Electric shocks aid math skills here.

Printable solar panels here.

armenian-rhapsody: By far the cutest little guy on the USS...

Sun, 19 May 2013 02:43:41 -0400

armenian-rhapsody:

By far the cutest little guy on the USS Enterprise

weareallstarstuff: Tornado Nebula

Sat, 18 May 2013 02:48:24 -0400

weareallstarstuff:

Tornado Nebula

apljax3: barackboomama: bluelippedlifelesskiss: a-r-i-s: thei...

Sat, 18 May 2013 02:42:01 -0400

apljax3:

barackboomama:

bluelippedlifelesskiss:

a-r-i-s:

theinturnet:

Finally.

I FINALLY UNDERSTAND.

WHY DON’T THY JUST SHOW US THIS CHART IN GEOGRAPHY???

DO YOU KNOW HOW LONG O HAVE USED GB AND ENGLAND AND THE UK INTERCHANGEABLY??????????????????????????????

A LONG ASS TIME. NONE OF MY TEACHERS EVER CORRECTED ME.

WTF, AMERICA.

dude wtf this is worse than us not using the metric system

I need to print this.

hydrogeneportfolio: Minimal Posters - Five Great...

Fri, 17 May 2013 20:27:54 -0400

hydrogeneportfolio:

Minimal Posters - Five Great Mathematicians And Their Contributions.

quantumeagle: I look up — many people feel small because...

Wed, 15 May 2013 23:23:59 -0400

quantumeagle:

I look up — many people feel small because they’re small and the Universe is big — but I feel big, because my atoms came from those stars. There’s a level of connectivity.

That’s really what you want in life, you want to feel connected, you want to feel relevant, you want to feel like a participant in the goings on of activities and events around you.

That’s precisely what we are, just by being alive…

- Dr. Neil DeGrasse Tyson [ x ]