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Today in science: The Day of 6 Billion

Global population reached 6 billion in 1999 and 7 billion in 2011. Today – October 12, 2017 – it stands at about 7.6 billion, according to United Nations estimates.

More than 450 volcanoes in Ring of Fire

The Pacific’s Ring of Fire has 75% of the world’s active and dormant volcanoes, plus it’s prone to powerful earthquakes. Here’s why.

Moon and Mercury after sunset August 4

It won’t be easy to catch Mercury near the August 4 young moon. But if your sky is clear all the way to the western horizon after sunset, try it!

Do no harm to life on Mars? Ethical limits of Prime Directive

A philosopher argues that now is the time to figure it out, before we make the inevitable discovery of extraterrestrial life.

Old under-ice volcanoes on Mars

An oddly textured region of southern Mars is not ice-covered today. Yet landforms here – and now certain minerals – are associated with under-ice volcanoes.

Kepler confirms 1,284 new planets

The announcement more than doubles Kepler’s confirmed exoplanets and suggests that, somewhere out there, we’ll discover another Earth.

Why Planet 9 shouldn’t exist

Earlier this year, scientists presented evidence for a Planet Nine in the far outer solar system. Scientists think it exists, but – if so – how did it get there?

A pure methane sea on Titan

We knew that Saturn’s moon Titan had seas and lakes of liquid hydrocarbons, but their exact composition was unknown until recently.

Just 40 light-years away, 3 potentially habitable planets

Earth-like planets aren’t exclusively orbiting sunlike stars. Ultracool dwarf star TRAPPIST-1 hosts 3 potentially habitable planets.

Orbit like a comet, rocky like an asteroid

They’re calling it a Manx comet, after the cats with no tails. It may have formed in the inner solar system and been ejected outward.

Astronomical events in 2016

A month by month listing of major moon phases, conjunctions, oppositions, meteor showers and other important dates, from astronomer Fred Espenak.

Inhospitable Danakil Depression hosts extreme life

It’s below sea level, with near-boiling water bubbling up from underground, high salt concentrations and toxic vapor. Yet life survives here.

Mars rover crosses most rugged terrain so far

The Curiosity rover has nearly crossed a stretch of the roughest terrain it’s seen during its 44 months on Mars. Scientists are monitoring the wear and tear on the rover’s wheels.

This date in science: Jan Oort’s birthday

Visualize a vast reservoir of icy comets on the outskirts of our solar system. That’s what Jan Oort did in 1950, and why the Oort Cloud bears his name.

Does this jellyfish look like a spaceship, or what?

Video of a spectacular jellyfish that floated past NOAA’s ROV on April 24, 2016 in the Mariana Trench – the deepest oceanic trench on the planet.

Dwarf planet Makemake has a moon

This Hubble Space Telescope image reveals the first moon ever discovered around little Makemake, in the outermost region of our solar system.

Dinosaurs already in decline before asteroid apocalypse?

New research suggests that dinosaurs were in decline tens of millions of years before the meteorite impact that finished them off.

What Venus Express learned by aerobraking

Results from the Venus Express spacecraft, obtained when – in the craft’s final months – it surfed the dense atmosphere of Venus.

Moon rocks reveal nearby supernova

Iron-60 found in moon rocks supports an earlier finding that – 2 million years ago – a supernova exploded only 300 light-years away.

Bubble Nebula looks like giant cosmic soap bubble

A new Hubble image captures – in stunning clarity – the Bubble Nebula, a cloud of gas and dust illuminated by the brilliant star within it.