From gravitational waves to weird radio signals, 2016 has been a busy year in the field of astronomy. With the constant deluge of ongoing news and controversies, it’s easy to lose sight of what’s happening in the world of outer space. So here are the top 10 stories in astronomical discoveries you should know about.
In March, NASA scheduled the launch of InSight, a spacecraft that would sit on the surface of Mars in an effort to measure Mars quakes. However, they discovered a vacuum leak in the Seismic Experiment for Interior Structure–a leak only a few nanometers across. Developing a patch for this would take too much time, so launch was delayed until 2018. On the bright side, this does allow extra time to fine-tune the sensors for more sensitive measurements when the mission does get underway. Even with this setback, Mars will still gain a visitor by way of ExoMars. This spacecraft, launched in March, is part of a multistep Mars program. The first mission will attempt to locate methane and other biologically important gasses via the Trace Gas Orbiter. In October, the mission released a test module, Schiaparelli, to demonstrate a controlled entry, descent, and landing. The lander, however, crashed on to the surface–though still operational. The next phase of the program is called ExoMars 2020 and hopes to land a rover safely.
After 10 years of examining data, scientists with the High Energy Stereoscopic System (HESS) have found some of the highest-energy particles ever observed coming from the center of our galaxy. This means there is something boosting these particles to such extremes. The HESS array of five telescopes doesn’t observe these high energy particles directly. When a highly energetic event happens–like a star exploding or a black hole flaring–the objects’ magnetic field can trap and force particles to cross a shock front thousands of times. Think of it like a child on a swing being boosted by a partner for each swing. By the time these particles escape they are moving almost as fast as light. When this happens the electrons and nuclei, known as cosmic waves, interact with other material. This generates high-energy gamma rays and lower-energy cosmic waves. All cosmic waves have an electric charge which means any magnetic field they encounter along the way will push or pull on them; however, gamma rays are electrically neutral, so if astronomers can catch them in motion they can trace them back to their source. Gamma rays don’t penetrate Earth’s atmosphere intact. Instead, they produce flashes of blue light as they travel through it. HESS detected a glow in the Milky Way that scientists say comes from protons accelerated to 10ˆ15 times the energies of visible light. The most obvious source is that it comes from the center of the Milky Way, a supermassive black hole. The study finds that the cosmic rays must have been continually emitted for at least 1000 years. More details will be available once the next-generation gamma-ray telescope–the Cherenov Telescope Array–comes online early next decade.
Yes, there has been the discovery of dwarf planets beyond Pluto–Eris, Haumea, Makemake–but over the past year, planetary scientists have found hints of a large, Neptune-sized planet beyond Pluto. Caltech’s Konstantin Batygin and Mike Brown researched characteristics of several small worlds orbiting in the scattered disk region–a band that spans 50 to 100 astronomical units (a unit of measure equal to the distance between the Earth and the Sun). They found that six worlds have an orbit that cross the solar system’s plane at the same angle and at similar locations. There’s only a .007 percent chance of this being due to random chance. After running computer simulations, the top possible cause indicates that a planet 10 times the mass of Earth is gravitationally shepherding these rocky worlds. However, this doesn’t define a discovery. Scientists need to observe the planet. Batygin and Brown have estimated this potential planet’s orbit and possible location, but so far they have come up empty. There have been two other objects proposed as well. Astronomers using the Canada-France-Hawaii-Telescope for their Outer Solar System Origins Survey announced a possible dwarf planet with an orbit bringing it as close to 34 AU and sends it out as far as 129 AU. They say that its size may be 480 miles across. Second, scientists with the Panoramic Survey Telescope and Rapid Response System discovered a bizarre object beyond Neptune they’ve nicknamed “Niku.” It’s orbit is nearly perpendicular to the ecliptic, only the second such object found.
If you attempt to star gaze tonight, you may find yourself staring through a haze of artificial light only a few stars can peak through. As of 2016, artificial light pollutes our night sky for around 83 percent of the population. That’s up from 66 percent in 2001. The numbers look even worse for the United States and Europe where 99 percent of those populations live under light-polluted skies. Researchers reviewed how many people can actually view the Milky Way on a dark night and its bad news–due to light pollution, the band of our galaxy is not visible for more than one-third of humanity.
On July 4, the Juno spacecraft finally reached Jupiter–its first Earthly companion in 13 years. And it was a tricky journey. Juno traveled at 130,000 miles mph when it approached Jupiter and had to perform a series of perfectly timed orbital maneuvers to get into orbit. Juno brings nine onboard science instruments to study the gas giant up close. However, Jupiter itself poses some issues to these delicate devices. Jupiter’s pressurized hydrogen and fast rotation generate a strong magnetic field which traps and accelerates particles to high energies. This can wreak havoc on Juno. Fortunately, Juno’s computer and many instruments are housed within a 400-pound vault of titanium. Also, Juno will orbit close to the poles of Jupiter to avoid the harshest radiation. That being said, Juno will deorbit and burn up into Jupiter by 2018 regardless if the instruments and devices last that long.
Almost a decade ago, West Virginia University astronomer Duncan Lorimer and his colleagues identified an odd signal in the archived data from Australia’s Parkes radio telescope. This signal appeared to come from outside our galaxy and only lasting for about a millisecond. Then, in 2013, astronomers uncovered more signals just like the one discovered by Lorimer. Some 17 fast radio bursts have been discovered with another half-dozen more as candidates. The leading theory–that the waves originate from the death of a star–doesn’t fit with a discovery made in 2016. Laura Spitler et al used Arecibo Observatory to periodically check on a known fast radio burst. What they saw was completely unexpected. The same source flared ten more times. This led them to believe that the source doesn’t destroy itself in the process. The challenge is to catch an FRB as it is blasting so they can trace it back to its source.
Although the New Horizons flyby happened in 2015, some of the data took until October 2016 to finally reach Earth. And then, of course, that data has to be analyzed. The biggest discovery is that Pluto had to have been active within the past several million years. This finding upends how scientists think about small worlds in our solar system. A study of polygon shaped structures on Pluto’s smoothest surfaces suggests that a warmer-than-expected interior brought warmer material from near the core and to the surface where it cooled. These polygon shaped chunks of nitrogen ice float on a plane of other ices, constantly being renewed. New Horizons’ mission has been renewed to study other Kuiper belt objects.
Launching into space is very expensive. A rocket’s main booster is discarded once its payload is launched into space. It falls back to Earth, lands in the ocean, and disappears never to be seen again. So, the idea of reusable rockets could save millions of dollars, making space flight more viable. Private companies like Blue Origin and SpaceX have been working for years to make reusable rockets a reality. Much attention is geared towards Space X, but the first company to successfully demonstrate a reusable rocket goes to Blue Origin. On November 23 of 2015, the company sent a rocket to 62 miles above the Earth surface and then safely landed back down on land. That same rocket was used two months later, reached a mile higher, and again landed vertically. On April 18 2016, SpaceX launched 7000 pounds of supplies to the International Space Station. Then, nine months later its first stage rocket landed on a ship in the Atlantic Ocean. They would repeat this process four more times over the coming months.
Over the years, astronomers have discovered thousands of exoplanets orbiting stars other than our Sun. But none of them are quite like Proxima Centauri b, a planet that could not only be terrestrial but could also contain water. Add that to the fact that it’s only 4.2 light years away–fairly close in astronomical terms. After finding hints of a wobble to the star Proxima Centauri, an international collaboration of astronomers convinced the European Southern Observatory to concentrate their telescope toward our Sun’s nearest neighbor. Their efforts uncovered a planet that is 1.3 times the mass of Earth and lies 5 percent of the distance that Earth lies from the Sun. There’s a high chance that this planet could harbor an atmosphere. This means that its temperature would allow for liquid water on its surface. There are a lot of unknowns when it comes to this planet but it is believed that the next generation of cameras will be able to photograph the exoplanet and learn not only if it has an atmosphere but if its chemistry hints at some biological life.
It was in the fall of 2015 when rumors began to swirl that advanced detection devices had picked up gravitational ripples emitted as mass moves through space. Then, in February 2016, it was confirmed by physicists at the Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) that they had detected gravitational waves by the merging of two black holes. It was the culmination of 50 years of technological advances, research, and a century of theoretical predictions. It opened up a new window of incite into our universe. It began with the two telescopes of Advanced LIGO, one in Livingston, Louisiana, and the other in Hanford, Washington. The engineers were at the last stages of an engineering run and testing ways the environment produces noise in detectors. When they ended the tests they kept the detectors running. Hours later, computer algorithms picked out of the data each telescope collected: an identical signal 7 milliseconds apart–the time being how long it took gravitational radiation to travel between the two telescopes. The signals gathered at Hanford and Livingston matched precisely what scientists would expect from general relativity. The science consortium–one thousand members strong–worked together, ruling out everything else it could be: Earth tremors, vehicles driving by near the detectors, etc. By January 21, 2016, the team was positive. They submitted a paper describing the observation. Three months later, another gravitational wave passed through the Earth. This was announced on June 15. What gravitational wave researchers are looking for is the unusual, unexpected, and bizarre. Says Amber Stuver, a LIGO team member, “I can’t wait until we find something that makes us scratch our heads and we have no idea what made it.”
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