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If Andromeda were brighter, this is how it would look in our night sky. They’re all out there, we just can’t see them
Distance to Earth: 2,538,000 light years

If Andromeda were brighter, this is how it would look in our night sky.
They’re all out there, we just can’t see them

Distance to Earth: 2,538,000 light years

(Source: laughing-treees, via fightingscholarlykrogan)

(Source: dimensao7, via shitthatiimagine)

itreallyisthelittlethings:

universe—cosmos:

Imagine how it would look if the Orion nebula is only four light years away - the distance the nearest star is to us, instead of 1,300 light years. It would be so bright that we wouldn’t be aware of the dark sky. We wouldn’t see other stars. The whole world would be the Orion nebula and the sun.

-The Universe 2x14: Nebulas

(via kitty-libertine)

sagansense:

gamma—crucis:

The Crab Nebula is a supernova remnant and pulsar wind nebula found in the constellation of Taurus. At it’s center lies a neutron star 28-30km across, that emits radiation from gamma rays to radio waves. It is not visible to the naked eye, but can be seen using a telescope or binoculars.

Image Credit: NASA, ESA, ESO

More on the history/discovery of the Crab Nebula, including my tattoos dedicated to this cosmic beauty, here.

thedemon-hauntedworld:

NGC 6888 Crescent Nebula Credit: Andrea Pistocchini

thedemon-hauntedworld:

NGC 6888 Crescent Nebula
Credit: Andrea Pistocchini

thedemon-hauntedworld:

Helix Nebula Extensions - Planetary Nebula in Aquarius The Helix nebula, NGC 7293 (Caldwell 63), in Aquarius is one of the most studied objects in the sky. It appears quite large because it is one of the closest planetary nebula (PN) to Earth at a distance of about 700 light years.
Credit: Don Goldman

thedemon-hauntedworld:

Helix Nebula Extensions - Planetary Nebula in Aquarius
The Helix nebula, NGC 7293 (Caldwell 63), in Aquarius is one of the most studied objects in the sky. It appears quite large because it is one of the closest planetary nebula (PN) to Earth at a distance of about 700 light years.

Credit: Don Goldman

thedemon-hauntedworld:

NGC 6744 A Galaxy Like Ours in Pavo NGC 6744 (Caldwell 101) is a magnificent barred spiral galaxy in the southern constellation of Pavo (The Peacock) about 30 million light years distant.
Credit: Don Goldman

thedemon-hauntedworld:

NGC 6744 A Galaxy Like Ours in Pavo
NGC 6744 (Caldwell 101) is a magnificent barred spiral galaxy in the southern constellation of Pavo (The Peacock) about 30 million light years distant.

Credit: Don Goldman

(Source: gravitationalbeauty, via dobie56)

we-are-star-stuff:


The Shkadov Thruster, or: How to Move an Entire Solar System
In about a billion years our aging sun will become hot enough to boil off Earth’s oceans. But we needn’t let our world bake to death. By devising a megastructure called a Shkadov Thruster, we could cruise our solar system - sun, planets, and all - close enough to a younger star for it to gravitationally capture Earth. By enabling us to swap our sun for another, the Shkadov Thruster could give the planet’s biota a brand new lease on life. 
"Shkadov Thrusters are kind of awesome," says Anders Sandberg, a research fellow at Oxford University’s Future of Humanity Institute who has studied Shkadov Thrusters amongst other megastructure concepts. "You can use it to move the whole solar system." 
The Shkadov Thruster setup is simple (in theory): It’s just a colossal, arc-shaped mirror, with the concave side facing the sun. Builders would place the mirror at an arbitrary distance where gravitational attraction from the sun is balanced out by the outward pressure of its radiation. The mirror thus becomes a stable, static satellite in equilibrium between gravity’s tug and sunlight’s push. 
Solar radiation reflects off the mirror’s inner, curved surface back toward the sun, effectively pushing our star with its own sunlight - the reflected energy produces a tiny net thrust. Voilà, a Shkadov Thruster, and humanity is ready to hit the galactic trail. 
Mirror Placement
If humanity were ever crazy or desperate enough to build a Shkadov, the first order of business would be deciding where to place the megastructure. Leonid Shkadov, the megastructure concept’s inventor, figured placement in the temperate orbital band where Earth resides would be fine. Still, much of the rear, space-facing side of the thruster would probably still need to be lined with cooling fins. These fins would radiate away excess solar heat in order to keep the mirror from deforming or melting, depending upon its material.
The thruster, of course, could not be positioned in Earth’s orbital path. A logical spot for it would be above or below the plane of Earth’s orbit, with the reflective mirror beaming energy mostly perpendicularly. For a thruster with a mirror angle of 30 degrees, the usual presumed curvature, Earth would still catch some extra rays. But the influence on Earth’s temperature is expected to be small, says Viorel Badescu, a thermodynamicist at the Polytechnic University of Bucharest in Romania, who has investigated so-called stellar engines, which include Shkadov Thrusters and Dyson Spheres. 
The second problem is simply acquiring enough material to build the behemoth structure. Badescu estimated that 1/10,000 of Earth’s mass would be required - probably about a sextillion pounds. Shkadov’s figure is a bit higher, more like septillion pounds. Either way, it’s hefty. 
Strip-Mining Mercury
Although the thruster would be vast - perhaps on the order of a few hundred million miles in diameter, or greater than the distance between the Earth and the sun - most of it would be thin, reflective material. “It’s probably going to be a lot of thin foil,” Sandberg says.
An excellent readily available material is hematite, which humans have been polishing into mirrors for millennia. A simple iron oxide, hematite could be obtained on a grand scale by essentially strip-mining the entire planet of Mercury. Although dismantling even a smallish planet like Mercury sounds tough, it still beats rounding up scattered asteroids, which wouldn’t provide enough usable material anyway.
"It’s much easier to disassemble existing planets than to collect bodies distributed over huge spaces," Badescu says. "The inner planets of the solar system probably would be the first source of material." 
[Continue Reading→]

we-are-star-stuff:

The Shkadov Thruster, or: How to Move an Entire Solar System

In about a billion years our aging sun will become hot enough to boil off Earth’s oceans. But we needn’t let our world bake to death. By devising a megastructure called a Shkadov Thruster, we could cruise our solar system - sun, planets, and all - close enough to a younger star for it to gravitationally capture Earth. By enabling us to swap our sun for another, the Shkadov Thruster could give the planet’s biota a brand new lease on life. 

"Shkadov Thrusters are kind of awesome," says Anders Sandberg, a research fellow at Oxford University’s Future of Humanity Institute who has studied Shkadov Thrusters amongst other megastructure concepts. "You can use it to move the whole solar system." 

The Shkadov Thruster setup is simple (in theory): It’s just a colossal, arc-shaped mirror, with the concave side facing the sun. Builders would place the mirror at an arbitrary distance where gravitational attraction from the sun is balanced out by the outward pressure of its radiation. The mirror thus becomes a stable, static satellite in equilibrium between gravity’s tug and sunlight’s push. 

Solar radiation reflects off the mirror’s inner, curved surface back toward the sun, effectively pushing our star with its own sunlight - the reflected energy produces a tiny net thrust. Voilà, a Shkadov Thruster, and humanity is ready to hit the galactic trail. 

Mirror Placement

If humanity were ever crazy or desperate enough to build a Shkadov, the first order of business would be deciding where to place the megastructure. Leonid Shkadov, the megastructure concept’s inventor, figured placement in the temperate orbital band where Earth resides would be fine. Still, much of the rear, space-facing side of the thruster would probably still need to be lined with cooling fins. These fins would radiate away excess solar heat in order to keep the mirror from deforming or melting, depending upon its material.

The thruster, of course, could not be positioned in Earth’s orbital path. A logical spot for it would be above or below the plane of Earth’s orbit, with the reflective mirror beaming energy mostly perpendicularly. For a thruster with a mirror angle of 30 degrees, the usual presumed curvature, Earth would still catch some extra rays. But the influence on Earth’s temperature is expected to be small, says Viorel Badescu, a thermodynamicist at the Polytechnic University of Bucharest in Romania, who has investigated so-called stellar engines, which include Shkadov Thrusters and Dyson Spheres. 

The second problem is simply acquiring enough material to build the behemoth structure. Badescu estimated that 1/10,000 of Earth’s mass would be required - probably about a sextillion pounds. Shkadov’s figure is a bit higher, more like septillion pounds. Either way, it’s hefty. 

Strip-Mining Mercury

Although the thruster would be vast - perhaps on the order of a few hundred million miles in diameter, or greater than the distance between the Earth and the sun - most of it would be thin, reflective material. “It’s probably going to be a lot of thin foil,” Sandberg says.

An excellent readily available material is hematite, which humans have been polishing into mirrors for millennia. A simple iron oxide, hematite could be obtained on a grand scale by essentially strip-mining the entire planet of Mercury. Although dismantling even a smallish planet like Mercury sounds tough, it still beats rounding up scattered asteroids, which wouldn’t provide enough usable material anyway.

"It’s much easier to disassemble existing planets than to collect bodies distributed over huge spaces," Badescu says. "The inner planets of the solar system probably would be the first source of material." 

[Continue Reading→]