About a month ago, a team of astronomers from different universities around the world discovered a bizarre dwarf galaxy, named Antlia 2 (or Ant 2), orbiting the Milky Way in the constellation Antlia.
Not only was Antlia 2’s enormous proportions atypical of a dwarf galaxy, but it was so dim and pale that it had gone undetected, until now – thanks to the European Space Agency’s Gaia satellite that provided the necessary data for the research team to sift through.
Antlia 2’s dimness, low density and the fact that it is hiding behind the Milky Way’s bright central disk are the reasons why it went undiscovered for as long as it did.
The relatively smaller size of most dwarf galaxies makes them defenseless against the gravitational forces of larger and more massive galaxies in their vicinity.
However, being larger than normal and the fact that it barely emits any light, Antlia 2 is kind of bizarre for a dwarf galaxy.
Researchers attribute Antlia 2’s low luminosity to the gravitational tides of the Milky Way.
Even though the Phantom galaxy is distant enough from the Milky Way to be ripped apart by its gravity, it does get influenced by the huge mass of the larger parent galaxy.
What the researchers have not been able to explain, though, is the disparity in Antlia 2’s mass and size.
With a relatively low mass, the ghost galaxy is vulnerable to the gravitational forces around it, because of which its size should have also been small, which is not the case – something the researchers have, so far, been unable to explain.
Under normal circumstances, the powerful forces of a much larger galaxy would cause the smaller galaxy to lose mass as well as condense, rather than grow.
For now, Antlia 2 may appear to be an “oddball” dwarf galaxy, but if researchers are able to locate more such galaxies, the oddity of Antlia 2 could possibly be better explained.
Parker Solar Probe
Earlier this year, NASA launched it’s $1.5 billion Parker Solar Probe on a seven-year mission that will take it deep into the sun’s atmosphere, the corona.
During this period, the instruments-loaded Parker will orbit the Sun 24 times, collecting important scientific data and beaming it back to earth.
If all goes well, researchers should have ample data by the end of the longish mission – not in space terms, though – to begin understanding the mysterious workings of our star, something that the scientific community has devoted decades towards.
Data such as 3-D images, electric and magnetic field recordings, and high-energy particle catalogs, to mention a few, will go a long way in helping them find long-elusive answers to most of their questions about the Sun and its corona.
It should, and probably will, enable scientists to safeguard spacecraft, astronauts, and sensitive ground equipment through improved space weather forecast, and much more, in times to come.
“It’s of fundamental importance for us to be able to predict this space weather, much like we predict weather here on Earth,” says NASA solar scientist Alex Young of the agency’s Goddard Space Flight Center in Maryland.
Not only is Parker expected to achieve record-breaking speeds of up to 450,000 miles per hour during the course of its multiple revolutions around the sun, it should also be able to get within 3.83 million miles of the star’s fiery surface – which is the closest it will get to it during its 7-year spin, creating yet another record.
The nearest that any spacecraft has ever got was a probe called Helios 2, which was able to make it to within 27 million miles, or 43 million kilometers, of the sun, way back in 1976.
2018 was another great year of photos and science on Mars for NASA’s nuclear-powered Curiosity rover, which was launched in 2011.
In June 2018, Curiosity found organic matter embedded in the sedimentary rocks of the three-billion-year-old Gale Crater on Mars, giving newfound impetus to the possibility that extraterrestrial life existed on the planet at some point in its past.
The organic molecules found in the ancient bedrock suggest that conditions back then may have been ideal to support some form of life, with a good chance that microorganisms once thrived on the red planet.
Despite numerous tests, researchers are unable to give a definitive reason for the formation of the organic matter, leaving open three main possibilities.
- The material had its origin elsewhere in the universe and was carried to Mars in a comet, or other such celestial bodies crashing into the Martian surface.
- They are the remnants of ancient organisms that lived on the planet billions of years ago.
- They are the by-products of chemical reactions that the rocks underwent over time.
Voyager 2 Entered Interstellar Space
NASA’s Voyager 2 spacecraft became the second human-made space plane to enter interstellar space after Voyager 1 achieved the feat in 2012.
Launched way back in in 1977, broke through the Sun’s heliopause and entered the void of interstellar space on Nov 5, 2018 – officially announced by the space agency on Dec 10.
While the heliopause is the boundary separating the Sun’s heliosphere from interstellar space, the heliosphere itself is a vast region surrounding the Sun that is dominated by its continuously expanding plasma known as the solar wind.
It is because of this solar wind that objects within this vast bubble of heliosphere, including Earth, are relatively better protected from the impact of galactic cosmic rays that are far more dominant beyond the heliopause – in interstellar space.
Voyager 2 is currently more than 11 billion miles from earth, getting farther and farther away as it hurtles through the interstellar void at 34,191 miles per hour (55,025 kph).
However, it is still 300 years short of entering the disc-shaped inner Oort cloud and another 30,000 years away from exiting the spherical outer Oort cloud, completely beyond the influence of the solar system.
Although more than a year has passed since a cigar-shaped asteroid came tumbling through our solar system, scientists learned a lot more about this interstellar intruder in 2018.
The cigar-shaped space rock was detected by astronomers at the Pan-STARRS 1 observatory in Hawaii, in Nov 2017, during a routine search of the skies for near-Earth objects on behalf of NASA.
The name Oumuamua is Hawaiian for a messenger from a distant past.
Studies based on the observations made during the 2017 flyby deemed it a strange interstellar object.
Rob Weryk, a postdoctoral researcher at the University of Hawaii Institute for Astronomy (IfA), said, “Its motion could not be explained using either a normal solar system asteroid or comet orbit.”
Further inspection of follow-up images from the European Space Agency’s telescope on Tenerife in the Canary Islands revealed that there was, indeed, something unusual about the object.
Estimated to be a quarter of a mile long, which is ten times its width, OUMUAMUA is dark reddish in color and elongated in shape, somewhat like a cigar, with no gas or dust surrounding it.
According to NASA, “Oumuamua is dense, comprised of rock and possibly metals, has no water or ice, and that its surface was reddened due to the effects of irradiation from cosmic rays over hundreds of millions of years.”
In November 2018, Harvard researchers submitted a paper that suggested Oumuamua could well be a fully operational probe sent to our solar system by some alien civilization.
However, many experts in the field are skeptical about the alien spacecraft theory, something that the authors of the paper, Avi Loeb, chairman of Harvard’s astronomy department, and Shmuel Bialy, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics were also not too sure of, calling it an “exotic scenario.”