Posts from the ‘planets’ Category

ikenbot:

How to Build a Planet: Heavy Metals Are Key Ingredients

Image: An artist conception of a newly formed star surrounded by a swirling protoplanetary disk of dust and gas, where debris coalesces to create rocky ‘planetesimals’ that collide and grow to eventually form planets. A new study suggests small rocky planet may actually be widespread in our Milky Way galaxy. Credit: University of Copenhagen, Lars A. Buchhave

Planets may not be able to form without a heaping helping of heavy elements such as silicon, titanium and magnesium, a new study suggests.

Stars that host planets have higher concentrations of such “metals” — astronomer-speak for elements heavier than hydrogen and helium — compared to iron than do planetless stars, the study found.

“To form planets, one needs heavy elements,” said lead author Vardan Adibekyan, of the Centre for Astrophysics of the University of Porto in Portugal.

Connected at birth

Planets coalesce from the disk of dust and gas left over after the birth of their parent star. According to the leading theory of planet formation, the core accretion model, small particles clump together, growing larger and larger until they produce protoplanets.

Scientists have long suspected that stars with higher metallicities are more likely to have planets orbiting them. Iron has long been a primary indicator.

“Usually, in stellar physics, people use the iron content as a proxy of overall metallicity,”

Full Article

A simplified demonstration of how planets move:

The planets orbit the sun in ellipses on a relatively flat plane

The sun is moving through space around a massive black hole in the middle of our galaxy, the Milky Way. This is the second part of the .gif, when the planets start spiraling.

The Milky Way is part of a cluster of galaxies called the Local Group, which orbit around a center between us and the Andromeda Galaxy.

And the Local Group is part of the Virgo Supercluster, which is one of millions to billions of superclusters in the observable universe.

Not to mention all of that is speeding “outward” as the universe expands. Probably. At speeds approaching light-speed. 

But despite all of this movement, we are able to shoot a rover attached to a lowering crane and hit a designated landing spot on one little planet. 

If that isn’t an awesome example of science, I don’t know what is.

world-shaker:

All 786 Known Planets (as of June 2012) to Scale

Planets are turning out to be so common that to show all the planets in our galaxy, this chart would have to be nested in itself—with each planet replaced by a copy of the chart—at least three levels deep.

(via http://xkcd.com/1071/large/)

Mmm, graphical science. From XKCD, no less.<3