Posts from the ‘universe’ 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,”

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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.

the-star-stuff:

NASA finds hidden ocean on Saturn’s moon Titan

Using incredibly precise measurements from NASA’s Cassini spacecraft, researchers have concluded that Saturn’s biggest moon is likely hiding a global, sub-surface water ocean, 100 km beneath its surface.

Cassini has flown by Titan more than 80 times since entering Saturn’s orbit in 2004, and its observations have confirmed that, as moons go, Titan is a weird one. It’s bigger than the planet Mercury. It’s the only moon with a real atmosphere (an atmosphere denser than Earth’s, in fact). It experiences Earthlike weather, such as rain and snow. It’s home to familiar geological features like valleys, plains and deserts — and it’s the only known object besides Earth with standing bodies of liquid.

The researchers’ findings are published in the latest issue of Science

quantumaniac:

Earth Will One Day See a Second Sun

Betelgeuse, a red supergiant star located in the Orion constellation, about 640 light-years away from Earth – is preparing to explode via a supernova. When it does, the Earth will have a front-row seat; in fact, the explosion will be so bright that Earth will seem to briefly have two suns in the sky. 

Betelgeuse is one of the brightest and largest stars in our immediate galactic neighborhood – if you dropped it in our Solar System, it would extend all the way out to Jupiter, leaving Earth completely engulfed. In stellar terms, it’s predicted to explode in the very near future. Of course, the conversion from stellar to human terms is pretty extreme, as Betelgeuse is predicted to explode anytime in the next million years.

But still, whether the explosion occurs in 2011 or 1002011 (give or take 640 years for the light to reach Earth), it’s going to make for one of the most unforgettable light shows in our planet’s history. For a few weeks, the supernova will be so bright that there will appear to be two stars in the sky, and night will be indistinguishable from day for much of that time. So don’t count on getting a lot of sleep when Betelgeuse explodes, because the only sensible thing for the world to do will be to throw a weeks-long global supernova party.

Physicist Brad Carter explains what Earth (and hopefully humanity) can look forward to:

“This is the final hurrah for the star. It goes bang, it explodes, it lights up – we’ll have incredible brightness for a brief period of time for a couple of weeks and then over the coming months it begins to fade and then eventually it will be very hard to see at all.”

Although there’ll be no missing the explosion, Carter points out that the vast majority of material shot out from the supernova will pass by Earth completely unnoticed:

“When a star goes bang, the first we will observe of it is a rain of tiny particles called neutrinos. They will flood through the Earth and bizarrely enough, even though the supernova we see visually will light up the night sky, 99 per cent of the energy in the supernova is released in these particles that will come through our bodies and through the Earth with absolutely no harm whatsoever.”

In any event, the Betelgeuse explosion will likely be the most dramatic supernova Earth ever witnesses – well, unless our Sun eventually explodes and destroys our planet, which would probably leave Betelgeuse the runner-up.

We should have a global supernova party every year anyway!