Space stories that shaped 2019: From Marsquakes and the Parker solar probe to the dark side of the Moon
From Marsquakes and discovering the second interstellar comet to reaching closer to the Sun than any other mission has done before, space news dominated the headlines in 2019
Looking back, 2019 has been an eventful year for space research, with scientists pushing the exploration of the Solar System to new frontiers.
Countries were seen racing against each other to make their presence felt on the Moon and beyond. Some of them have their eyes set on Mars, with attempts already being made to uncover some of its mysteries. Here are some of the important discoveries that made headlines in 2019.
Mars saw a lot of action
In 2019, we found out that Marsquakes are a thing. Mars experiences tremors at least twice each day, according to NASA's InSight Mission that has been recording quakes, since its arrival in 2018.
Recording the first such quake in April this year, the InSight has detected 322 Marsquakes until now, say scientists. Though common, most of the quakes are mild, of magnitudes that are barely felt on Earth.
But a couple of them have been big — up to nearly magnitude 4. Scientists are hoping to study what lies beneath the planet's surface, which could, in turn, throw light on what is driving Marsquakes.
In addition to Mars' trembling surface, scientists also found fluctuations in the levels of gases — methane and oxygen — circulating above. In June, NASA's Curiosity rover detected a large spike in methane.
This gas is usually produced by living things on Earth, leading scientists to speculate whether this was evidence of potential microbial life on the Red planet.
When NASA conducted a follow-up experiment, they saw a decrease in their levels, as they returned to normalcy. This remains a mystery as previous papers have documented how background levels of the gas seem to rise and fall seasonally.
Similarly, scientists detected varying amounts of oxygen. Throughout spring and summer, the amount of oxygen in the air rose by as much as 30% and then dropped back in fall, baffling scientists.
"We are struggling to explain this. The fact that oxygen behavior is not perfectly repeatable every season makes us think that it's not an issue that has to do with atmospheric dynamics," says Melissa Trainer, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who led this research.
But scientists are placing their bets on two options — both biological and geological. They are also wondering if an unknown force is driving the unusual behavior of both methane and oxygen.
The only thing scientists can do at the moment is to speculate. Neither the curiosity rover nor the four new spacecraft scheduled to land on Mars next year have instruments on them that can study these gases and explain its behavior.
Another interesting finding could explain how Mars lost its lakes and rivers. A satellite — NASA's Mars Reconnaissance Orbiter — orbiting Mars, caught a raging, giant storm, ferrying water vapor from the surface into space.
Scientists believe that these storms may have had some role to play in transforming the planet into the freezing, dry desert it is today.
Though now Mars' water reserves have been stripped off, scientists know that Mars was once home to sprawling rivers. According to a study published this year, Mars had hundreds of them. Fed by run-offs, these rivers used to be wider than those found on Earth.
If water existed in the form of rivers, there is no reason to not believe that the planet may have supported life in its prime. NASA and ESA will be launching a mission that will hunt for ancient life.
To that end, both space agencies zeroed in on a perfect site to look for fossil records of microbes: Jezero Crater, which was once home to an ancient river delta.
Second interstellar comet visits Solar System
This year, our solar system played host to a visitor from beyond. Called comet 2I/Borisov, the visitor was a comet from another star.
Initial observations revealed that the Borisov comet was strikingly similar to our native comets — with both carrying water. But what is exciting is scientists think that 2I/Borisov could be carrying water from another star.
We estimate an H2O (water) active area of 1.7 square km, which for current estimates for the size of 2I/Borisov suggests active fractions between 1-150%, consistent with values measured in solar system comets,” says the pre-print version of the study.
This discovery, according to the research team, raises questions whether other planetary systems are similar to ours.
This is the second such visit from a foreign object. Only last year, an interstellar object named Oumuamua cruised through our solar system. It was confirmed in October 2017.
In the future, more interstellar objects may drop by. Scientists anticipate that future large surveys like the Large Synoptic Survey Telescope (LSST) — which is scheduled to be operational in 2022 — will find approximately one per year.
Record number of asteroids whiz past Earth
A record number of asteroids — over 2,100 — have hurtled past Earth, of which 175 approached the planet in November, according to the European Space Agency (ESA), which monitors and raises alarms of possible collisions.
Since these objects pose a significant threat, NASA and ESA are keeping an eye on possible future collisions. Meanwhile, Japanese astronauts have been successful in bringing home samples from asteroids.
In November, the Japan Aerospace Exploration Agency's Hayabusa 2 collected space rocks from asteroid dubbed Ryugu, and is expected to touch down in late 2020. By studying these rocks, scientists are hoping to understand the history of the rocky body.
This is the second such asteroid sample-return mission ever. The Japanese agency picked up samples from an asteroid named Itokawa way back in 2010.
NASA scientists will also be carrying out a similar expedition. The space agency will be studying asteroid Bennu, a Near-Earth Object — which could one day threaten Earth.
NASA launched its OSIRIS-REx spacecraft, which is currently orbiting the asteroid, mapping its surface. The analysis revealed that Bennu has a rugged surface, dotted with boulders — making landing a challenge.
But after carefully analyzing Bennu's surface for a year, the spacecraft has selected a landing site for sample collection. If the landing goes according to plan, the spacecraft will return home with bits of Bennu in 2023.
Moon's unexplored side
China scripted history this year by landing on Moon's unexplored side, also called the far side of the Moon. Their spacecraft named Chang'e 4 is currently exploring the Aitken Basin on the far side of the Moon.
Earlier this year, China tested whether lunar soil can support the growth of plants. They were successful after the cotton seed taken to the Moon had successfully germinated — becoming the first such plant to sprout in Moon's harsh conditions. But this was shortlived, and the plant died in the lunar cold.
With China's success, researchers hope Chang'e 4 will help answer questions about the formation of the Moon.
Another mystery scientists are hoping to solve is to understand how the Moon contains water ice. "Getting data on the ice [would] be game-changing," planetary scientist Philip Metzger of the University of Central Florida in Orlando told ScienceNews.
"There's a good chance that much of this ice came to the moon on comets, and Earth could have gotten its water and other ingredients for life in a similar way. Studying the lunar ice could offer clues about when it arrived and where in the solar system it originated," he adds.
NASA, on the other hand, is returning humans to the Moon through their Artemis Mission, scheduled for 2024. A trip to the Moon could also help astronauts find water —a resource that future explorers could tap into when they venture deep into space.
Parker solar probe reaches closer to the sun
NASA became the first space organization to have a close rendezvous with the Sun, through their Parker Solar Probe. The Probe has gone where no other object from Earth has ventured before, collecting a huge chunk of data that can reveal the secrets of the Sun.
The Parker Probe Mission was created to uncover why the solar wind — the particles from the sun that could knock out satellites and electrical grids or endanger the health of astronauts in orbit — is accelerated to tremendous speeds that reach 250 to 750 kilometers per second and why the sun's outer atmosphere, or corona, is so much hotter than its surface.
Analyzing data released by the probe this year helped scientists trace the source of solar winds.
Scientists already knew that the fast solar wind originates in large coronal "holes" — patches where the outer atmosphere is considerably cooler and thinner than normal — near the sun's pole. Now, we know that the slow solar wind originates from holes that appear closer to the Sun's equator.
Space travel's impact on health
Before astronauts embark on a voyage to the Moon and beyond, NASA conducted a study to understand the toll long-term space travel could take on humans.
In 2019, NASA released results of the effects of long-term spaceflight. The study included identical twins — Scott Kelly and Mark Kelly. While Scott spent 340 days on the space station, his twin stayed back on Earth.
While in orbit, Scott showed mutations in DNA and performed poorly in some cognitive tests. On his return, Scott bounced back — reversing most of those changes, while still retaining a few.
"Given that the majority of the biological and human health variables remained stable, or returned to baseline, after a 340-day space mission, the data suggest that human health can be mostly sustained over this duration of flight," concludes the analysis.