planet

This video explains the difference between a planet, like Earth, and a dwarf planet, like Pluto. 

There once were two planets, new to the galaxy and inexperienced in life. Like fraternal twins, they were born at the same time, about four and a half billion years ago, and took roughly the same shape. Both were blistered with volcanoes and etched with watercourses; both circled the same yellow dwarf star—close enough to be warmed by it, but not so close as to be blasted to a cinder. Had an alien astronomer swivelled his telescope toward them in those days, he might have found them equally promising—nurseries in the making. They were large enough to hold their gases close, swaddling themselves in atmosphere; small enough to stay solid, never swelling into gaseous giants. They were "Goldilocks planets," our own astronomers would say: just right for life.

A new planet was discovered that is similar to Earth in size and composition, meaning it has a rocky surface and an iron core. But that is where similarities end. This twin, named Kepler-78b, has an orbit so close to its parent star, that the surface is about 2,000 degrees hotter than Earth's. The planet's orbit around the star takes only 8.5 hours, instead Earth's 12 month orbit. Located 400 light years away from Earth in the constellation Cyngus, this hellish Earth shouldn't exist. For a planet only 20% larger than Earth with such a small orbit, astronomers can't figure out how it was formed.

Via NASA:

The sprawling Caloris basin on Mercury is one of the solar system's largest impact basins, created during the early history of the solar system by the impact of a large asteroid-sized body. The multi-featured, fractured basin spans about 1,500 kilometers in this enhanced color mosaic based on image data from the Mercury-orbiting MESSENGER spacecraft. Mercury's youngest large impact basin, Caloris was subsequently filled in by lavas that appear orange in the mosaic. Craters made after the flooding have excavated material from beneath the surface lavas. Seen as contrasting blue hues, they likely offer a glimpse of the original basin floor material. Analysis of these craters suggests the thickness of the covering volcanic lava to be 2.5-3.5 kilometers. Orange splotches around the basin's perimeter are thought to be volcanic vents.

Made up of rock and iron, this planet is thought to be tidally locked to it's parent star (meaning one side always faces the star), it is also much closer to it's host star than the Earth is to the Sun. This means that the "day" side of the planet is always molten, and that's just awesome.

This planet, GJ 504b, is about the size of Jupiter, but has several times its mass. It's actually so far the smallest planet that's ever been directly imaged with a telescope, rather than being observed by eclipsing its parent star.

...one of Einstein's weirder ideas has led to the identification of a new planet, about twice as massive as Jupiter, orbiting a star some 2,000 light-years from Earth — a discovery Einstein never even envisioned but one that may never have happened without him. Indeed, David Latham, a Harvard astronomer who collaborated on the discovery, originally doubted it was even possible to do what he (under Einstein's guiding hand) recently succeeded in doing. "I thought it was silly," he say

Astronomers studying a newborn star have caught a detailed glimpse of planets forming around it, revealing a never-before seen stage of planetary evolution.

It took nine years and 3 billion miles, but at 7:49 a.m. EST the New Horizons spacecraft passed what was once the furthest planet in our solar system.

Traveling at a speed of 30,800 miles per hour, New Horizons zoomed by Pluto a scant 7,800 miles away. This is the closest we have ever got to Pluto and it will send back some of the best images of the maligned dwarf planet we have ever seen. Maybe this will convince those scientists to let it back into the club and give us the nine planets that we deserve.

But we've learned a lot so far. For instance, now we know how big the dang thing is.

This morning, NASA announced that Pluto is 2,370km (about 1,473 miles) in diameter, give or take 20m. That makes it ever so slightly bigger than Eris, a much darker and denser object that lives farther out in the Kuiper Belt. (Eris measures 2,336km in diameter.) Measurements of Pluto's size before today were estimates at best, their accuracy skewed by the dwarf planet's hazy atmosphere.

We've also learned that Pluto has a pretty big ice cap, filled with lots of nitrogen and frozen methane. (I could've told you the place was cold nine years ago.)

Since this mission happened billions of miles away and it takes four hours for the radio waves New Horizon sends us to be uploaded, we shouldn't expect to see any pictures filled with happy, waving aliens until tonight.

Also, by the way, the download speed on that information is 1 Kb/s. Dialup hell.

Here's a video explaining the delicacy and scale of this Pluto flyby:

As we got closer to the dwarf planet, however, all anyone could see was the image of Mickey Mouse's dog, carefully hidden within the terrain.

#Pluto in Pluto (Last pic from before @NASA #flyby) http://t.co/k10eyMg05V @NASANewHorizons pic.twitter.com/seidGQzxyX

— Boing Boing (@BoingBoing) July 14, 2015