Via Freudian Slip 'N Slide
"The vast distances that separate the stars are providential. Beings and worlds are quarantined from one another. The quarantine is lifted only for those with sufficient self-knowledge and judgement to have safely traveled from star to star."
—Carl Sagan, Pale Blue Dot, 1994
Arthur C. Clarke, Stephen Hawking and Carl Sagan
this is probably my favorite thing on the internet.
Yes yes yes on so many levels
Aw their smiles
Galactic Rotation and Dark Matter:
Stars near the center of a spiral galaxy orbit at roughly the same velocity as stars near the edge of a galaxy, for the Milky Way this is about 220km per second, or 140 miles per second. And that is weird. very weird.
Normally objects in orbital motion move much slower the further away from the center they get, like the planets around the sun - earths velocity is less than that of Venus. So when astronomers discovered this they knew that it must mean there is mass that cannot be seen, and not centered in the same way as regular matter (not all concentrated at the center of the galaxy.)
This is one of the main pieces of evidence for dark matter.
Models with dark matter spread throughout the galaxy and further confirm this, so now imagine the galaxy as a solid, uniform sphere rather than a bunch of point masses congregating towards the center. Objects orbiting within a uniform sphere only experience the gravitation pull of matter below their orbit, and basically completely ignore everything above them. Its one of those nice mathematically-provable things where everything cancels out. This means that as an object moves further away from the center the net gravitational pull increases exactly proportionally so its speed stays the same.
At first glance a spiral galaxy may look as if the edge stars are slower than the center ones, but in reality if that were true the arms would become so elongated and twisted that it would be hard to tell one spiral arm from its neighbors.
This same effect can be applied to the solar system - Neptune’s orbit is faster than it should be. however the effect does not compare to the effect seen on the galactic scale.
A multi-year study of the Whirlpool galaxy (M51) has changed our understanding of giant molecular clouds, in which stars are born. The new study, which mapped 1,500 such clouds, shows that, instead, they are embedded in a kind of molecular fog, which permeates the whole of the galactic disc. Pressure exerted by this fog is crucial in determining whether or not new stars will form within the clouds. The study, led by Eva Schinnerer from the Max Planck Institute for Astronomy, made extensive use of the millimeter telescopes of IRAM, the Institut de Radioastronomie Millimétrique.
Most of a galaxy’s stars are born within giant molecular clouds - accumulations of hydrogen molecules with total masses between a thousand and several million times that of our Sun. As a region within such a cloud collapses under its own gravity, it contracts until pressure and temperature are high enough for nuclear fusion to set in: a new star is born.
Christmas is coming, and since a few of you have asked me where to get these i thought i would just put them all in one list, so;
- Aerogel - (currently out of stock, sorry.)
- Ecosphere - Comes in many different shapes; Large Sphere, Small Sphere, Small Pod/oval and more.
- Could not find a Gomboc, sorry.
- Gallium - 20 grams, 40 grams, 100 grams
- Miracle Berries - A lot cheaper than i thought they would be!
- Ferrofluid/Magnetic Fluid - heres a bonus gif :D
Via That Science Guy
The much anticipated comet Ison appears to have largely been destroyed from its pass around the sun, something may have survived however the show everyone has been looking forward to has been cancelled.
YTMND’s presentation of our future in all its horrifying glory.
Via That Science Guy
Anonymous asked: think leonardo da vinci wouldve made a great scientist?
He was, to an extent.