The other galaxies are there, but they are hiding a very long way away.
We are in the Milky Way. If you travelled on an extremely fast spaceship for more than two million years, you would reach our neighbour, the Andromeda galaxy. All other galaxies are even further away.
About a century ago, we didn’t even know that galaxies existed.
Mai Lam/The Conversation NY-BD-CC
Pretty much as soon as we understood what galaxies were, we realised they are all moving away from each other. And the ones that are further away are moving faster. In short, the universe is expanding.
The Sombrero galaxy reveals the extremes of age and shape.
NASA/ESA and The Hubble Heritage Team (STScI/AURA)
As galaxies get older they get rounder, and fall victim to the middle-aged spread that catches many of us humans here on Earth.
An artist’s impression of the predicted merger between our Milky Way (right) and the neighboring Andromeda galaxy (left). So which galaxy will dominate?
NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger
Bigger galaxies tend to dominate the smaller, when the two collide. But the pending battle between our Milky Way and the Andromeda galaxy might be a much fairer fight than we previously thought.
: X-ray: NASA/CXC/SAO; Optical: Rolf Olsen; Infrared: NASA/JPL-Caltech
Strangely behaving galaxies force scientists to rethink whether the universe really is uniform.
ESO/UltraVISTA team. Acknowledgement: TERAPIX/CNRS/INSU/CASU
Massive, far distant galaxies contain 100 times more gas than we thought possible.
An image by MeerKAT shows hydrogen gas in M83, a famous spiral galaxy.
A precursor to the Square Kilometre Array- the MeerKAT telescope - is being built right now and remarkable progress has been made in the last 12 months.
Gravitational lensing (arcs and streaks in the picture) in the galaxy cluster Abell 370.
Galaxies evolve in mysterious way. But a new study offers a fresh approach to understand them.
Here, an alien crew member, Saru on Star Trek: Discovery. We often rely on science fiction to guide our expectations of alien life. We can hope lessons about accepting beings very different from yourself can be extracted by the series end.
(Courtesy of CBS Studios)
Star Trek: Discovery explores our corner of the block -- just a fraction of the galaxy. Some stars are better candidates for intelligent alien life, and it may not be anything like we imagine.
Detecting cosmic ray particles: a water-Cherenkov detector seen against the night sky at the Pierre Auger Observatory in western Argentina.
Steven Saffi, University of Adelaide
Scientists say they now know that high energy cosmic ray particles that bombard Earth are coming from outside our galaxy. But the actual source still remains a mystery.
So many galaxies viewed by the Hubble Space Telescope: but what’s their real shape in 3D?
NASA, ESA, and J. Lotz and the HFF Team (STScI)
The first reliable measure of the 3D shape of galaxies and their rotation helps to shed light on their history.
Part of the new map of dark matter made from gravitational lensing measurements of 26 million galaxies in the Dark Energy Survey.
Chihway Chang/University of Chicago/DES collaboration
We still can't see the dark matter thought to make up about a quarter of the universe, but at least now we have a map of its structure.
In the beginning, the Universe expanded very, very fast.
What caused the Big Bang is still a mystery. And that's just one of the many unanswered questions, in spite of everything we do know about the birth of the Universe.
ESO provides new ways to access the southern sky for Australian astronomy.
ESO/José Francisco Salgado
Australia's new partnership with the European Southern Observatory will give our astronomers access to much bigger telescopes.
The truth is we don’t really know if space goes on forever – but maybe, one day, we will find out.
People used to think that when they looked up at the night sky, they were seeing all of space. Then American astronomer Edwin Hubble found out something so amazing, NASA named a telescope after him.
Artist’s impression of ZF-COSMOS-20115, a galaxy that stopped making new stars and rapidly turned into a compact red galaxy.
The recipe book for galaxy formation may need to be rewritten after the discovery of a massive galaxy that stopped making new stars early in the Universe's history.
The Australian Square Kilometre Array Pathfinder uses several telescopes to survey the sky.
After months of running in test-mode, the Australian Square Kilometre Array Pathfinder telescope is now gathering data at an incredible rate to give us a new look at how our universe works.
Jets generated by supermassive black holes at the centers of galaxies can transport huge amounts of energy across great distances.
REUTERS/X-ray: NASA/CXC/Tokyo Institute of Technology/J.Kataoka et al
It's difficult to get jets - powerful, lightning fast particles - to give up their secrets. The new Square Kilometre Array radio telescope could hold the key to solving jets' mysteries.
Light from the universe’s first galaxies destroyed the hydrogen atoms that formed during the Big Bang.
NASA, ESA, R. Ellis (Caltech), and the UDF 2012 Team
A new telescope aims to figure out what became of the universe's original atoms once the first stars began to shine.
A small section from the ZFOURGE survey, which contains thousands of galaxies spanning billions of years.
Hundreds of images of thousands of galaxies have given astronomers one of the most detailed galaxy studies ever compiled.