Enjoying EarthSky? Subscribe.

267,484 subscribers and counting ...

Saturn moon Titan has a sea level

A new topographic map of Titan, plus a new study showing that Titan’s seas lie at an average elevation – a sea level – just as Earth’s do.

How massive can neutron stars be?

Settling a long debate, astrophysicists at Goethe University Frankfurt now say neutron stars can’t exceed the mass of 2.16 suns.

Supercomputer insights on mysterious black hole jets

Scientists used the Blue Waters supercomputer to show that a black hole’s relativistic jets and accretion disk both may be spinning – and precessing over time – around an axis separate from the black hole itself.

Zooming star points to black hole in globular star cluster

Globular star clusters contain our galaxy’s most ancient stars. Astronomers didn’t expect to find a 4-solar-mass black hole in one, but … voila!

No double moon in 2018, or ever

2018 will be an excellent year to view Mars. The planet will be closer to Earth – and brighter in our sky – than since 2003. But as big as the moon? Heck no.

Our Milky Way as a “melting pot”

Where do stars we see at night come from? Newly confirmed streams of stars – thought to be coming to our Milky Way from other galaxies – suggest not all Milky Way stars were born here.

Astronomers detect whirlpool movement in earliest galaxies

Astronomers looked back to a time only 800 million years after the Big Bang and found whirlpool shapes in small, very young galaxies.

EarthSky’s 2018 meteor shower guide

Plan ahead now for an awesome year of meteor-watching. Good news! In 2018, the year’s 2 most reliable showers – August Perseids and December Geminids – happen with little to no interference from the moon.

Scientists expect 1st direct black hole image soon

In 2018, scientists hope to obtain the 1st-ever direct image of a black hole’s event horizon. They’re targeting the 4-million-solar-mass black hole at the heart of our Milky Way.

A 3D journey through the Orion Nebula

Astronomers and visualization specialists at NASA have just released this unprecedented, 3-dimensional, fly-through view of the Orion Nebula, a nearby star-forming region.

Mars life clues from methane and ‘sticks’

The Curiosity rover has made 2 new and interesting discoveries – the first about methane in Mars’ air and the other about stick-rock formations – both related the possibility of life.

Sun in zodiac constellations, 2018

Sun-entry dates to zodiac constellations in 2018, using boundaries for constellations set by International Astronomical Union in 1930s.

Fast radio bursts: A mystery unfolds

Repeating, short, unpredictable radio bursts left astronomers perplexed. Now they think the bursts were twisted by the extreme environment around a supernova or supermassive black hole.

New year’s comets

Will 2018 give us a bright comet? There are a couple of possibilities. In the meantime, here are some photos of comets, visible through telescopes, as 2018 begins.

10 places to find snow beyond Earth

From NASA, here are 10 snowy or icy worlds beyond our own.

No alien megastructure for Tabby’s Star

This star’s odd, sporadic dimmings and brightenings caused speculation about vast structures built by alien civilizations. But a crowd-funded observing campaign led to a different conclusion.

Did our solar system form in a bubble around a giant star?

And now … a big bubble theory. Scientists are discussing the possibility that our solar system formed in wind-blown bubbles around a giant, long-dead star.

2018’s closest supermoon January 1

January has 2 full supermoons. Earth’s western hemisphere has its 1st one on the 1st full night of 2018. Eastern hemisphere? Your fullest supermoon is January 2.

Are December’s solstice and January’s perihelion related?

December solstice 2017 was December 21. Earth is closest to the sun for 2018 on January 2-3. Coincidence?

Next New Horizons flyby will happen a year from today

The New Horizons flyby of Kuiper Belt object 2014 MU69 – a year from today, on January 1, 2019 – will be the most distant in the history of space exploration.