![Image of the dark matter halo of a massive galaxy cluster takes shape, with small halos forming and merging into larger ones](/sites/default/files/styles/2015_inset_one/public/images/standard/dark-matter-02-1000x1000.jpg?itok=-427scv3)
The dark matter halo of a massive galaxy cluster takes shape, with small halos forming and merging into larger ones.
![Image of tracing the pathlines of dark matter in the universe](/sites/default/files/styles/2015_inset_one/public/images/standard/dark-matter-pathlines-large.jpg?itok=ZZnwS39r)
Tracing the pathlines of dark matter in the universe.
![Image of exploring dark matter streams](/sites/default/files/styles/2015_inset_one/public/images/standard/dm-splatting-large.jpg?itok=LV5TdSZR)
Exploring dark matter streams.
![Image of small galaxies take shape in the early universe](/sites/default/files/styles/2015_inset_one/public/images/standard/dwarf-galaxy-02-1000x1000.jpg?itok=Vj_wp8I-)
Small galaxies take shape in the early universe.
![Image of a view of a massive star in the early universe as it perishes in a supernova explosion](/sites/default/files/styles/2015_inset_one/public/images/standard/first-light-red-blue-1000x1000.jpg?itok=qJ4XA1D6)
A view of a massive star in the early universe as it perishes in a supernova explosion.
![Image of three stars in the early universe heat up before they are consumed in gigantic supernova explosions](/sites/default/files/styles/2015_inset_one/public/images/standard/first-stars-1000x1000.jpg?itok=bUMnCFTT)
Three stars in the early universe heat up and partly clear their surroundings before they are consumed in gigantic supernova explosions.
![Image of large-scale structures and massive galaxies form in the early universe](/sites/default/files/styles/2015_inset_one/public/images/standard/galaxy-merger-02-1000x1000.jpg?itok=s1mHzo5m)
Large-scale structures and massive galaxies form in the early universe—the central galaxy in this visualization represents about 1 trillion solar masses.
![Image of A visualization of the speed of hydrogen gas in a rotating galaxy from the early universe](/sites/default/files/styles/2015_inset_one/public/images/standard/galaxy-velocities-large.jpg?itok=3DS5Dg7v)
A visualization of the speed of hydrogen gas in a rotating galaxy from the early universe. Yellow lines represent fast-moving gas; purple lines are regions of slower-moving gas.
![Image of a spiral galaxy](/sites/default/files/styles/2015_inset_one/public/images/standard/galaxy-zoom-large.jpg?itok=4hK4m13K)
A spiral galaxy.
![Image of A superbright star in the early universe charges up surrounding hydrogen, setting the stage for galaxy formation](/sites/default/files/styles/2015_inset_one/public/images/standard/massive-star-1000x1000.jpg?itok=bH2193vq)
A superbright star in the early universe charges up surrounding hydrogen, setting the stage for galaxy formation.