Other Discoveries

• The largest known ring around Saturn

Saturn's stunning ring system has been photographed extensively, but those portraits have not revealed the planet's largest ring. The wispy structure is a diffuse collection of particles that orbits Saturn much farther from the planet than any of the other known rings. The ring starts about six million kilometers (3.7 million miles) away from the planet. It is about 170 times wider than the diameter of Saturn, and about 20 times thicker than the diameter of the planet. If we could see the ring with our eyes, it would be twice the size of the full Moon in the sky.

One of Saturn's farthest moons, Phoebe, circles within the ring and is likely the source of its material. The relatively small numbers of particles in the ring don't reflect much visible light, especially out at Saturn's orbit where sunlight is weak, which is why it remained hidden for so long. Spitzer was able to detect the glow of cool dust in the ring, which has a temperature of about minus 316 degrees Fahrenheit or minus 193 degrees Celsius, which is 80 Kelvin.

•  'Big baby' galaxies

Spitzer has made major contributions to the study of some of the earliest-forming galaxies ever studied. The light from these galaxies takes billions of years to reach Earth, and thus scientists see them as they were billions of years ago. The most distant galaxies observed by Spitzer radiated their light about 13.4 billion years ago, or less than 400 million years after the birth of the universe.

One of the most surprising discoveries in this area of research was the detection of "big baby" galaxies, or those that were much larger and more mature than scientists thought early-forming galaxies could be. Scientists believe large, modern galaxies formed through the gradual merger of smaller galaxies. But the "big baby" galaxies showed that massive collections of stars came together very early in the history of the universe.

• Black Hole

Black holes are some of the strangest and most fascinating objects in outer space. They're extremely dense, with such strong gravitational attraction that even light cannot escape their grasp if it comes near enough. 

Albert Einstein first predicted the existence of black holes in 1916, with his general theory of relativity. The term "black hole" was coined many years later in 1967 by American astronomer John Wheeler. After decades of black holes being known only as theoretical objects, the first physical black hole ever discovered was spotted in 1971. 

Then, in 2019 the Event Horizon Telescope (EHT) collaboration released the first image ever recorded of a black hole. The EHT saw the black hole in the center of galaxy M87 while the telescope was examining the event horizon, or the area past which nothing can escape from a black hole. The image maps the sudden loss of photons (particles of light). It also opens up a whole new area of research in black holes, now that astronomers know what a black hole looks like.

So far, astronomers have identified three types of black holes: stellar black holes, supermassive black holes and intermediate black holes.

• The Death of a Zombie Star

Scientists already have a strong understanding of what happens when a star dies and how supernovas work, but in 2018, astronomers discovered that iPTF14hls appears to have died and come back to life multiple times. What’s going on with this so-called zombie star? Normally, when a star dies, it emits a bright light for a short period of time while imploding during a supernova event. But,  even though iPTF14hls seemed like it died about 60 years ago, it now appears to be pulsing, with a brighter-than-normal supernova.

• A New Galaxy With No Apparent Dark Matter

Most of the material in the universe is dark matter, but a Milky Way-sized galaxy named NGC 1052-DF2 seems to be missing this essential ingredient for a galaxy. Astrophysicist Alberto Conti of Northrop Grumman explained, “‘In astronomy, if we don’t know what something is, we call it ‘dark.'” According to Science Daily, NGC 1052-DF2 only has 1/400th of the expected amount of dark matter, which remains a mystery to scientists.

• Detecting the Oldest Stars in the Universe

Another discovery in 2018 gives us some new clues about dark matter. A team of American astronomers detected signals from the oldest stars in the universe, which formed just 180 million years after the Big Bang, according to Sky & Telescope. The absorption was stronger than predicted, suggesting that the gas the starlight had passed through was colder than expected. So what stole the energy? Sky & Telescope explained that the thief was likely dark matter, which presumably interacted with ordinary matter in the early days of the universe.