By Kevin Roeten:
First Interstellar Visitor
Astronomers have located a lost asteroid shaped like a CIGAR traveling within our solar system. Evidently it has become our first interstellar visitor after wandering the galaxy for hundreds of millions of years. The dark red object named Oumuamua, is the first space rock from outside the solar system ever observed by astronomers. The dark red rock in Hawaiian means messenger. It is about 1,312 feet long and highly-elongated. It is 10 times as long as it is wide, according to a study reported in Nature journal.
Discovered on October 19, the object is several hundred feet across and is currently speeding away from us at more than 98,000 miles an hour. At that speed, the space rock is moving fast enough to outrun the sun’s gravitational tug. With all its current properties, it has directly implied it never came from our solar system. Astronomy postdoctoral researcher Rob Weryk saw something strange. In images from the university’s Pan-STARRS 1 telescope, he spotted a speck in the night sky seeming to move far too fast to comfortably orbit the sun.
Please keep in mind no one has actually seen Oumuamua yet [or will], and it seems difficult to discern exact size, weight, and length of the asteroid. Looking at its rotation rate, it’s spinning in unusual spin and is totally dark during times of the day. This object, known as A/2017 U1, is the first interloper of appreciable size flying through our cosmic galaxy. The object could give scientists an unprecedented, if fleeting, opportunity to stare straight at the leftovers of an alien planet.
Per Dr. Karen Meech, Oumuamua is roughly 1,312 feet long. It’s incredibly dense, likely made up of a rocky or high metal content, though it has no water or ice. The reddish color could be a result of irradiation from cosmic rays, which the asteroid could have been exposed to over the millions of years it’s been traveling through space. According to NASA, both Hubble and Spitzer telescopes are still tracking Oumuamua. As of November 20, it’s currently traveling at 85,700 mph. It’s expected to pass through Jupiter’s orbit in May 2018, followed by Saturn’s orbit in January 2019.RY5
Meech, from the Institute for Astronomy in Hawaii, said: “Oumuamua may well have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with the solar system. is unusually large variation in brightness means that the object is highly elongated: about 10 times as long as it is wide, with a complex, convoluted shape. We also found it has a dark red color, similar to objects in the outer solar system, and confirmed…it is completely inert, without the faintest hint of dust around it.”
Who Spotted Oumuamua First?
Oumuamua originated from outside the solar system.
The asteroid’s properties suggest it lacks significant amounts of water or ice. Astronomers think several interstellar asteroids pass through the inner solar system about once a year, but that‘s highly unlikely. Is it constructed to visit this system and report back to its keeper what they found? To date, there has been no asteroid found resembling this size and shape. When what looks like a rocket stage, or even an interstellar ship from Arthur C. Clarke’s science-fiction novel, Rendezvous with Rama. Soon sober-minded reporters were exchanging curious messages: Could this ‘asteroid’ actually be an alien artifact? How would we know?
On October 19, an interstellar asteroid was detected by the Pan-STARRS 1 telescope in Hawaii. While it was initially classified as a comet, additional observations revealed it to be an asteroid originating from interstellar space. Its surface has been darkened and reddened by the impact of cosmic rays over millions of years. Astronomers go by the 1.8 meter Pan-STARR telescope in Hawaii, pictured above, which is part of a system set up to track potentially threatening Near Earth Objects.
Interestingly, the asteroid’s trajectory seemed to be headed directly towards our sun but, has changed course to come extremely close to earth. Let’s go over several details. First, it is highly elongated—not typical for an asteroid. Second, without a doubt it has roamed the galaxy for hundreds of millions of years. Third, it is totally inert with no water. Fourth, it seems to be able to change course on a whim. Fifth, it’s never been encountered before, at least by humans. Fifth, it’s traveling at over 86,000 mph.
Discovery and orbit determination. The October 19 detection of ‘Oumuamua
Specifics included the Pan-STARRS1 telescope used four ‘sidereally’ tracked with band images obtained in poor seeing conditions during normal survey observations for near-Earth objects. Two additional band pre-discovery images from 2017 October 18 were then identified in images with stellar FWHMs of 1.8’’ and 2.4’’. It was not possible to detect low-level cometary activity in these images due to poor seeing and the object being trailed. Both elliptical and parabolic heliocentric orbits gave atypically large fit residuals when additional astrometry beyond the original detections were included. Follow-up observations with the ESA Optical Ground Station also did not fit, and were blocked by the Minor Planet Center [MPC] automated routines as suspected outliers. Our investigation revealed this object could be explained using a hyperbolic orbit—the largest ever recorded.
Oumuamua was first classified as an Aten-type object (semimajor axis, a = 0.74 au, e = 0.449, inclination, i = 10°) when it was posted to the Near-Earth Object Confirmation Page [NEOCP]. The Aten-type orbit induced a 5 degree arc minute error in its predicted location 24 hours later and increased to 34 arc minutes after 48 hours. It was later classified as a Halley-family comet when the Minor Planet Center revised the orbit to [a = 50 au, e = 0.997, i = 107°] after including the Catalina Sky Survey observations on October 20 and the ephemeris error for our pre-discovery observations decreased from 34 to 0.5 arc minutes. The object’s orbit was seen to be clearly hyperbolic after the arc was extended to October 22 by our CFHT observations. With additional Canada-France-Hawaii Telescope astrometry on 2017 October 22 UT, the eccentricity was revised to e = 1.188 ± 0.016. With a total of 131 observations [eleven of which were rejected as outliers] ‘Oumuamua’s orbital eccentricity is now securely hyperbolic at the 100 σ confidence level, having a barycentric eccentricity of e = 1.1929 ± 0.0006 . The two most significant planetary close approaches were with the Earth and Jupiter, but even they are too distant to significantly perturb ‘Oumuamua.’
Oumuamua got another new designation, introducing a naming scheme never used before: 1I/2017 U1 (I for interstellar). Officially named ‘Oumuamua, the asteroid was spotted by the Pan-STARRS 1 telescope in Hawaii on October 18. Its inbound speed of about 25.5 kilometers per second and its slingshot route around the sun pegged it as the first interstellar vagabond ever seen.
Researchers had long theorized space should be full of comets and asteroids ejected from other solar systems during their early days. Their models showed planetary formation is a messy business, with many small objects kicked out as big proto-planets form. `Oumuamua is the first proof that they were right. It’s also our first direct look at an intact visitor, as opposed to dust specks from another solar system. But there wasn’t much of a chance to study it. By the time `Oumuamua was discovered it was already past the sun, on its way back to the stars and off into the darkness. Astronomers at the world’s major observatories rushed to see what they could learn from it. They began amazing, rapid-fire studies. And what they found was…rather odd.
`Oumuamua rotates rapidly, every 7.3 hours. As it spins, its brightness changes drastically, indicating a highly elongated shape. Karen Meech at the University of Hawaii’s Institute for Astronomy concluded the asteroid is about 400 meters long but only one tenth as wide. The asteroid is similar to some of the objects in our solar system’s distant Kuiper Belt, but also broadly similar to some metallic asteroids.
Those unexpected traits caught the attention of a number of armchair scientists on the European Southern Observatory. They released a pair of evocative illustrations of `Oumuamua, including the one at the top of this post. The thing doesn’t look natural. So here we are again: Could it be artificial? How would we know?
Obvious giveaways might be emitting radio signals, or some other artificially modulated form of radiation. It may likely adjust its course in some way. It might give off a heat signature indicating some kind of engine or internal energy source. engine or internal energy source. Could this be a dead, abandoned spaceship? Could it perhaps be instrumented, but not actively powered? Nobody has ever looked at Oumuamua in the far Infrared.
There are so many ‘ET’ ideas to consider it’s impossible to state with complete certainty Oumuamua is not somehow associated with an intelligent alien civilization—not yet. Still, Occam’s Razor says it’s possible the very first object we ever see from interstellar space could be a spaceship–a slow, inert, disguised spaceship–built by aliens. Aliens whom we have no evidence actually exist.
Andy Rivkin at Johns Hopkin’s Applied Physics Lab reminded me of a great test case. In 2002, astronomers noticed a small, fast-spinning object in an unusual Earthlike orbit. Spectroscopic observations revealed rough matches with aluminum and paint containing titanium oxide. The object was quickly identified as an Saturn V rocket upper stage, probably from Apollo 12. But Oumaumau has not been possibility as anything known—yet.
Granted, we knew what to look for when trying to identify an Earth rocket. Granted further, an alien artifact floating through space for millions of years could be heavily altered by radiation and micrometeorites. But still–there’s nothing about Omuamua looking fake, but certainly ‘surreally’ strange. But the final reasoning, is Oumuamua is different. For planet-formation, models suggest 1-10 interstellar objects pass through our solar system every year! We haven’t seen them before because they tend to be fast and faint. New tools like the Pan-STARRS survey finally caught one happening to pass especially close to the sun.
Future surveys will be more sensitive, and now scientists will be looking more actively for other visitors to see if they are like `Oumuamua or if they are something else entirely. The Large Synoptic Survey Telescope will be revolutionary in its determination of what Oumuamua actually represents. Now, Oumuamua is a class of one. We don’t know what it actually is, or if it atypical of the objects zooming past us from our galaxy, or entirely other star systems.
Already we can see from its motion Oumuamua does not seem to be associated with any of the nearby stars. We will see how many interstellar objects are rocky asteroids and how many are icy comets. And maybe, just maybe if any of those objects show any sign of artificial origin, there’s an excellent chance we’ll know that, too.
Kevin Roeten can be reached at roetenks@CHARTER.NET.
© Copyright by Kevin Roeten, 2017. All rights reserved.