1936 … Coming Soon! By James Vaughan

Pluto’s twilight zone

NASA’s New Horizons spacecraft took this stunning image of Pluto only a few minutes after closest approach on July 14, 2015. The image was obtained at a high phase angle –that is, with the sun on the other side of Pluto, as viewed by New Horizons. Seen here, sunlight filters through and illuminates Pluto’s complex atmospheric haze layers. The southern portions of the nitrogen ice plains informally named Sputnik Planum, as well as mountains of the informally named Norgay Montes, can also be seen across Pluto’s crescent at the top of the image.

Credit: NASA/JHUAPL/SwRI

Entering vacuum…

Patrol the inner Solar System and defend your homeworld!

The moon is pretty rad.

Cone Nebula

A large, faint emission nebula and bright galactic association of stars known as The Christmas Tree Cluster form object NGC 2264, which itself contains a unique feature known as the Cone Nebula. The Cone Nebula’s shape comes from a dark absorption nebula consisting of cold molecular hydrogen and dust in front of a faint emission nebula containing hydrogen ionized by nearby star S Monocerotos, the brightest star of NGC 2264. The faint nebula is approximately seven light-years long and is 2,700 light-years away from Earth.

Credit: David M. Jurasevich

Our universe seems to be getting bigger and bigger.

10 Times More Galaxies!

The universe suddenly looks a lot more crowded…

We already estimated that there were about 100 billion galaxies in the observable universe, but new research shows that this estimate is at least 10 times too low!

First, what is the observable universe? Well, it is the most distant part of the universe we can see from Earth because, in theory, the light from these objects have had time to reach Earth.

In a new study using surveys taken by the Hubble Space Telescope and other observatories, astronomers came to the surprising conclusion that there are at least 10 times more galaxies in the observable universe than previously thought. This places the universe’s estimated population at, minimally, 2 trillion galaxies!

The results have clear implications for galaxy formation, and also helps shed light on an ancient astronomical paradox – why is the sky dark at night?

Most of these newly discovered galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way.

Using deep-space images from the Hubble Space Telescope and other observatories, astronomers converted the images into 3-D, in order to make accurate measurements of the number of galaxies at different epochs in the universe’s history.

In addition, they used new mathematical models, which allowed them to infer the existence of galaxies that the current generation of telescopes cannot observe. This led to the surprising conclusion that in order for the numbers of galaxies we now see and their masses to add up, there must be a further 90% of galaxies in the observable universe that are too faint and too far away to be seen with present-day telescopes.

The myriad small faint galaxies from the early universe merged over time into the larger galaxies we can now observe.

That means that over 90% of the galaxies in the universe have yet to be studied! In the near future, the James Webb Space Telescope will be able to study these ultra-faint galaxies and give us more information about their existence.

So back to the question…Why is the sky dark at night if the universe contains an infinity of stars? Researchers came to the conclusion that indeed there actually is such an abundance of galaxies that, in principle, every patch in the sky contains part of a galaxy.

However, starlight from the galaxies is invisible to the human eye and most modern telescopes due to other known factors that reduce visible and ultraviolet light in the universe. Those factors are the reddening of light due to the expansion of space, the universe’s dynamic nature, and the absorption of light by intergalactic dust and gas. All combined, this keeps the night sky dark to our vision.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Stars and Dust Pillars in NGC 7822 from WISE.

js

NASA originally commissioned these posters for an exhibit at the Kennedy Space Center Visitor’s Complex in 2009. As part of their Journey to Mars, these versions are now available to everyone online. 

Credit: NASA/KSC

Star Dust - by Dmitry Vishnevsky