- Scientists made dozens of exciting new discoveries in space this year.
- Unprecedented photos revealed the far side of the moon, the first black hole was captured on camera, and astronomers spotted a comet from another star system.
- Spacecraft also ventured to new destinations, diving through the sun’s atmosphere, landing on an asteroid, and sending back data from interstellar space.
- These are the 26 biggest space breakthroughs of 2019.
- Visit Business Insider’s homepage for more stories.
This year was full of astronomical breakthroughs in space.
Photos captured phenomena nobody had ever seen before. Ambitious spacecraft revealed new secrets about the sun and the edges of our solar system. Astronomers spotted the brightest light in the universe, found new planets circling distant stars, and detected a collision between a black hole and a neutron star that warped the fabric of space-time.
Here are the 26 biggest discoveries and achievements in space from 2019.
On New Year’s Day, NASA’s New Horizons probe snapped unprecedented photos of the most distant object any spacecraft has ever visited.
After New Horizons flew past Pluto in July 2015, its long journey to the edge of our solar system took it to a distant space rock nicknamed Arrokoth. The probe snapped hundreds of photographs as it flew by the space rock at 32,200 miles per hour on New Year’s Day.
Arrokoth, which was previously nicknamed “Ultima Thule,” is more than 4 billion miles from Earth.
Just a few days later, China landed on the far side of the moon — the first time humanity had ever achieved that feat.
On January 3, the Chang’e 4 mission touched down on the side of the moon we can’t see from Earth. The spacecraft sent back the first photos ever taken from that part of the moon’s surface.
It turned out to be a year of photographic firsts. Researchers stitched together 7,500 photos taken over 16 years by the Hubble Space Telescope. The result was this unprecedented mosaic of the deep universe.
The image above, published in May, contains about 265,000 visible galaxies crammed into a region smaller than the moon’s apparent size in the sky. The light from some of those galaxies comes from 13.3 billion years years ago, just 500 million years after the Big Bang.
A worldwide team of scientists also released the first photo ever taken of a black hole.
The unprecedented photo, published in April, shows the supermassive black hole at the centre of the Messier 87 galaxy, which is about 54 million light-years away from Earth. The black hole’s mass is equivalent to 6.5 billion suns.
Scientists struggled for decades to capture a black hole on camera, since black holes distort space-time, ensuring that nothing can break free of their gravitational pull – even light. That’s why the image shows a shadow in the form of a perfect circle at the centre.
The following month, the supermassive black hole at our galaxy’s centre suddenly lit up, suggesting that it may have swallowed something big.
In May, the supermassive black hole at the centre of the Milky Way suddenly flashed twice as brightly as scientists had seen in 20 years of observation. Nobody knows what caused the flash, but two objects that passed near the black hole in 2014 and 2018 could be the culprits.
“We think that something unusual might be happening this year because the black hole seems to vary in brightness more, reaching brighter levels than we’ve ever seen in the past,” Tuan Do, an astronomer and lead author of the paper about the finding, told Vice.
In August, scientists detected what they think was a collision between a black hole and a neutron star (the super-dense remnant of a dead star) for the first time ever.
Gravitational-wave detectors in the US and Italy picked up ripples in space-time from that event as they passed through Earth.
Gravitational waves were first theorised by Albert Einstein, who predicted in 1915 that accelerating massive objects, like neutron stars or black holes, would create “waves” in the fabric of space and time.
The first observations of gravitational waves, however, didn’t come until 100 years later. In 2015, researchers detected waves from two black holes colliding, and in 2017 they observed two neutron stars merging.
Scientists think this year’s waves came from a black hole swallowing a neutron star 1 billion years ago. If confirmed, this would be the third type of event detected using gravitational waves.
Another violent space explosion, called a gamma-ray burst, emitted the brightest, most energetic light in the universe. Scientists saw that light for the first time.
Telescopes had previously observed low-energy rays that come from the initial gamma-ray burst and the afterglow. But scientists had never caught the ultra-high-energy light until these two recent observations.
The second burst, captured in January, produced light containing about 100 billion times as much energy as the light that’s visible to our eyes.
“It turns out we were missing approximately half of their energy budget until now,” Konstancja Satalecka, who coordinates telescope searches for gamma-ray bursts, said in a press release after the findings were released in November. “Our measurements show that the energy released in very-high-energy gamma-rays is comparable to the amount radiated at all lower energies taken together. That is remarkable.”
Yet another explosion may have annihilated the most massive star ever known to die in a supernova. It lasted over 800 days, longer than any supernova seen before.
Scientists think this may be the first observation of a rare type of supernova– the final explosion of a dying star – that completely annihilates its star, leaving nothing behind.
“Everything about this supernova looks different – its change in brightness with time, its spectrum, the galaxy it is located in, and even where it’s located within its galaxy,” Edo Berger, the author of an August study that described the event, said in a press release. “We sometimes see supernovas that are unusual in one respect, but otherwise are normal; this one is unique in every possible way.”
This could be how the most massive stars in the universe die.
While some discoveries offered promising answers, others just raised more questions. New measurements of the universe’s expansion highlighted a “crisis in cosmology” that could require a “new physics.”
The universe is always getting bigger, stretching galaxies farther apart. But measurements of the contemporary universe show it’s expanding much faster than the standard model of its history predicts.
“Therein lies the crisis in cosmology,” Chris Fassnacht, an astrophysicist and co-author of a study about this, said in a press release.
This year, one study found that the universe is expanding 9% faster than calculations based on radiation from the Big Bang would predict. Other research has reached similar conclusions using different techniques.
Scientists think these mismatched measurements show that something is missing from their model of the universe. They just don’t know what.
“It could be exotic dark energy, or a new relativistic particle, or some other new physics yet to be discovered,” astrophysicist Sherry Suyu said in a release about a December study on the topic.
Other discoveries this year happened by accident. An amateur astronomer spotted the second object ever known to enter our solar system from interstellar space.
The comet, called 2I/Borisov, came from an unknown star system. It’s only the second interstellar object ever found passing through our solar system.
Crimean amateur astronomer Gennady Borisov first spotted the comet on August 30. Now it’s hurtling past the sun at 100,000 miles per hour, passing outside Mars’ orbit. It’s making its closest approach to Earth this month, getting no closer than 190 million miles (300 million kilometers).
The first interstellar object ever seen, the mysterious and cigar-shaped ‘Oumuamua (which a few scientists controversially argued could be alien in origin), sped past Earth at a distance of 15 million miles in October 2017.
“The main difference from ‘Oumuamua and this one is that we got it a long, long time in advance, ” Olivier Hainaut, an astronomer with the European Southern Observatory, told Business Insider when the comet was first reported in September. “Now astronomers are much more prepared.”
As 2I/Borisov was visiting from outside our solar system, scientists released findings from the Voyager 2 spacecraft’s journey into interstellar space.
Voyager 2 found a mysterious extra layer outside our solar system.
The probe entered interstellar space in December 2018, six years after its sister spacecraft, Voyager 1, which reached the limits of the solar system in 2012. But a plasma-measuring instrument on Voyager 1 had been damaged, so that probe could not gather crucial data about the transition from our solar system into interstellar space.
The discovery of these boundary layers suggests there are stages in the transition from our solar bubble to the interstellar space beyond that scientists did not know about until now.
NASA also released new findings from another spacecraft: the Parker Solar Probe. The high-speed probe discovered never-before-seen activity at the edges of the sun’s atmosphere.
Since it launched in August 2018, the Parker Solar Probe has rocketed around the sun three times, getting closer than any spacecraft before it and travelling faster than any other human-made object in history.
The probe’s early data, released in December, revealed reversals of the solar magnetic field and “bursts” in its stream of electrically charged particles, called solar wind.
This solar wind washes over Earth, so the Parker probe could help scientists figure out how to protect astronauts and Earth’s electric grid from unpredictable, violent solar explosions.
The spacecraft is set to zip around the sun 21 more times in the next six years.
A Japanese spacecraft landed on an asteroid after blasting it with a bullet in order to collect samples of subsurface rock. Japan plans to bring those rocks to Earth.
In July, the Hayabusa-2 spacecraft collected deep rock from Ryugu, a primitive asteroid half-a-mile in diameter that orbits the sun at a distance up to 131 million miles.
Some asteroids date back to the dawn of our solar system 4.5 billion years ago, when materials leftover from the formation of planets coalesced into these chunks of rock. In that sense, asteroids can serve as time capsules: What scientists find in those primitive rocks could tell us a lot about the solar system’s history.
Below Ryugu’s surface, rock is sheltered from the wear and tear of space. It might contain amino acids, the essential building blocks of life.
If successful, Hayabusa-2 will be the first mission to bring samples from such an asteroid back to Earth.
NASA launched an atomic clock into space in June. The super-accurate timekeeping technology could one day serve as a kind of GPS in deep space.
The Deep Space Atomic Clock (DSAC), which is the size of a four-slice toaster, is designed to keep time that’s accurate to within one-ten-millionth of a second over the span of a year.
The experiment launched aboard a SpaceX Falcon Heavy rocket.
The super-accurate timekeeping technology could one day allow robotic and crewed spaceships to compare their local time to times broadcasted by atomic clocks on Earth. This would allow them to calculate their location and speed and navigate the solar system autonomously, without instructions from Earth.
“If we get out to Mars, the crew is going to want to know where they’re at, and they will need to know it – potentially in real-time – in case they have to make last-minute course adjustments,” Todd Ely, the leader of the DSAC experiment, previously told Business Insider.
The first solar sailing spacecraft hitched a ride on the same rocket as the atomic clock. The technology could help future spacecraft achieve interstellar travel.
This type of solar sail could one day enable spacecraft to travel beyond the solar system, since it’s continuously pushed through space by the pressure of photons.
“Solar sails are just ideal,” Bill Nye, head of the Planetary Society, which led the mission, said in a video. “People have speculated on using solar sails as cargo ships to take material to Mars and so on.”
In March, SpaceX launched Crew Dragon, making it the first commercial spaceship designed for humans ever to leave Earth.
“This is an amazing achievement in American history,” Jim Bridenstine, NASA’s administrator, said during a broadcast after the landing. He described it as “the dawn of a new era in American human spaceflight, and really in spaceflight for the entire world.”
Outside our solar system, astronomers found a wealth of new exoplanets. Last week, NASA confirmed a new class of huge ‘super-puff’ planets that have the density of cotton candy.
Until recently, astronomers had only known about the three types of planets that we see in our own solar system: terrestrial planets like Earth, ice giants like Neptune, and gas giants like Jupiter.
But on Thursday, NASA confirmed that three exoplanets fall into the new super-puff grouping. Because their hydrogen-helium atmospheres balloon out, these planets are nearly as big as Jupiter, but have 100 times less mass.
Nobody knows why the planets’ lightweight atmospheres are so bloated.
Researchers also discovered several new super-Earths — planets larger than Earth but not large enough to be Neptune-like.
A batch of new exoplanets announced on Monday included four super-Earths, which appear to be vaporizing in the intense heat of their stars.
Some recently discovered super-Earths are in their stars’ habitable zones — the range of distances in which a planet’s surface could be the right temperature for liquid water.
A few of the new super-Earths were among the closest exoplanets ever found.
One of the newly discovered planets, called GJ 357 d, is just 31 light-years away, scientists announced in July. It’s among the 45 closest exoplanets confirmed to date, out of a total 4,025 planets tallied so far outside our solar system.
“GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the sun,” Diana Kossakowski, who’s on the team that discovered the planet, said in a press release.
“If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface,” she added.
In September, scientists announced they had found water vapour in the atmosphere of an Earth-sized planet in a nearby star’s habitable zone.
However, other scientists have said that the planet, called K2-18b, is too big to be a super-Earth. At eight times Earth’s mass, they say the planet is probably more like Neptune, with a thick atmosphere that exerts high pressure on the planet’s surface and makes it inhospitable to life.
Even if K2-18b isn’t the right place for life, billions more planets in our galaxy could meet those standards.
An August study found there could be up to 10 billion Earth-like worlds in the Milky Way galaxy alone.
More and more evidence indicates that warm, watery planets like Earth are common in our galaxy.
Researchers at Penn State University ran the numbers by creating a simulation based on the Kepler Space Telescope’s search for exoplanets. They calculated that an Earth-like planet likely orbits one in every four sun-like stars. Totaled up, that means there could be up to 10 billion Earth-like worlds in our home galaxy.
Even worlds that aren’t Earth-like could have a shot at hosting alien life. In October, NASA found organic compounds in the ocean of Saturn’s moon Enceladus.
These compounds, which carry nitrogen and oxygen, play a key role in producing amino acids - complex molecules that serve as the building blocks of proteins. Without proteins, life as we know it on Earth couldn’t exist.
Scientists have long suspected that the ocean below Enceladus’ surface could harbour the ingredients for life. Researchers had detected other organic molecules coming from the icy moon before, but in October, they announced they’d detected them dissolved in the water for the first time. That’s critical, since it means the compounds could undergo deep-sea chemical reactions that produce amino acids.
Mars, by contrast, is unlikely to host life today. But this month, NASA scientists found a region where future astronauts could dig up subsurface ice with a shovel.
Water ice sits just an inch below the surface in the vast temperate region pictured above.
It could be the perfect place for astronauts to land, since any crew that visits the red planet would have to mine resources there, and water is the most important one. Mars astronauts would need to dig up ice to make drinking water and to create rocket fuel for the journey back to Earth (when you break down water into oxygen and hydrogen, the latter can be used to make fuel).
“Bringing your own water from Earth would be incredibly expensive,” Sylvain Piqueux, the NASA planetary scientist who led the research, told Business Insider. “Everything that you don’t have to bring with you leaves more room for a science experiment or additional engineering capabilities.”
NASA’s Insight lander has been on Mars since November 2018. In April, its built-in seismometer detected the first Mars quakes.
Since then, researchers have recorded more than 100 events, about 21 of which are likely quakes. The Mars quakes suggest the red planet may be less Earth-like than we thought.
Researchers had expected quakes on Mars to be like earthquakes, since Mars once had plenty of volcanic activity and water. They also thought the planet had a similar crust to Earth. But the Mars quakes so far seem more similar to quakes on the moon than on Earth, which suggests Mars‘ crust is more dry and broken up than scientists anticipated.
“A moon quake builds up for minutes, then decays away for an hour or more. So it looks very different,” Mark Panning, a seismologist on the NASA InSight team, previously told Business Insider. “The reason moonquakes look that way is because the moon’s surface is really dry and really broken up. It’s been basically sitting there for billions of years and getting hit by meteorites.”
Research about other planets in the solar system revealed surprises, too. Scientists discovered that a huge planet may have crashed into Jupiter about 4.5 billion years ago.
In an August study, researchers calculated that Jupiter probably absorbed a young planet with 10 times the mass of Earth after a head-on impact.
The ancient collision would explain why Jupiter’s core is less dense and more diffuse than scientists expected.
“Because it’s dense, and it comes in with a lot of energy, the impactor would be like a bullet that goes through the atmosphere and hits the core head-on,” Andrea Isella, an astronomer at Rice University and a co-author of the study, said in a press release. “Before impact, you have a very dense core, surrounded by atmosphere. The head-on impact spreads things out, diluting the core.”
Astronomers also spotted 20 more moons orbiting Saturn than they knew about before, bringing the planet’s total up to 82.
That’s more than any other planet in the solar system.
Each of the newly discovered moons is about 3 miles (5 kilometers) in diameter, and 17 of them orbit in retrograde, or in the opposite direction of Saturn’s rotation. One of them is now the farthest known moon of Saturn.
This was a big year for breakthroughs in space, but 2020 might be even bigger.
NASA is set to launch a new Mars rover in July 2020, and the European Space Agency plans to launch one as well. NASA and SpaceX, meanwhile aim to launch the first astronauts on the Crew Dragon in the first quarter of the year.
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