Last week, a small asteroid was detected just two hours before it impacted Earth’s atmosphere. Luckily, it was only about 3 meters (10 feet) wide, and the space rock, now known as 2022 EB5 likely burned up in Earth’s atmosphere near Iceland at 21:22 UTC on March 11.
While it is wonderful that astronomers can detect asteroids of that size heading towards our planet — as well as determine the asteroid’s trajectory and precisely predicted its impact location — the last-minute nature of the discovery definitely causes a pause. What if it had been bigger?
The new movie “Don’t Look Up” — now available on Netflix — is not your usual sci-fi disaster film. Instead, it is a biting parody on the general public’s dismissal and indifference to science. While the movie is about a comet on a collision course with Earth, filmmakers originally meant “Don’t Look Up” to be a commentary on climate change denial. But it also is reflective of the current COVID denial and mask/vaccine resistance, as well as our existing political polarization. It also lays bare our preoccupation with social media. While the movie is sometimes funny, it can also be depressing and frustrating.
The outer reaches of the Milky Way galaxy are a different place. Stars are much harder to come by, with most of this “galactic halo” being made up of empty space. But scientists theorize that there is an abundance of one particular thing in this desolate area – dark matter. Now, a team from Harvard and the University of Arizona (UA) spent some time studying and modeling one of the galaxy’s nearest neighbors to try to tease out more information about that dark matter, and as a result came up with an all new way to look at the halo itself.
Two more comets – 88P Howell and M3 ATLAS – are worth scouting the sky for into November 2020.
If you’re like us, you’ve been at taking advantage of every clear night during quarantine to get out and observe the night sky. Thankfully, 2020 has thus far been a ‘comet year,’ with a steady string of binocular comets, led by bright comet C/2020 F3 NEOWISE this summer. Fall is seeing another surge in comets topping +10th magnitude. Late October sees a brief dawn apparition of Comet C/2020 P1 NEOWISE and now, two other comets grace the dawn and dusk skies.
Last July, a once-in-a-lifetime event happened. Not the good kind; the football-field-sized-asteroid near-miss kind. And that near miss is the catalyst for a renewed effort from NASA to detect more dangerous space-rocks that might threaten Earth.
Last summer’s near-miss asteroid was named 2019 OK, and it passed within about 77,000 km (48,000 miles) of Earth. It managed to slip past all of our detection methods and came within 0.19 lunar distances to Earth. In astronomical terms, that is remarkably close.
We only had 24 hours notice that the asteroid was coming, thanks to a small telescope in Brazil that spotted it. That near miss has sparked a renewed conversation on planetary defense and on NASA’s role in it.
It also left people wondering how this could happen.
NASA’s Wide-field Infrared Survey Explorer (WISE) accomplished much during its first mission, which ran from December of 2009 to September of 2010. During the many months that it was active, the orbital telescope conducted an all-sky astronomical survey in the infrared band and discovered thousands of minor planets and numerous star clusters.
The extension of its mission, NEOWISE, has brought new life to the telescope as a comet and asteroid hunter. And since its re-activation in December of 2013, the orbiting telescope has spotted hundreds of Near Earth Objects (NEOs) and thousands of Main Belt asteroids. Most recently, it has detected two new objects (both possibly comets) which could be observable from Earth very soon.
The most recent object to be detected – 2016 WF9 – was first observed by NEOWISE on November 27th, 2016. This comet’s path through the Solar System takes it on a circuitous route, taking it from Jupiter to just inside the orbit of Earth over the course of 4.9 years. Much like other objects of its kind, 2016 WF9 may have once been a comet, or part of a population of dark objects in the Main Asteroid Belt.
In any case, 2016 WF9 will approach Earth’s orbit on February 25th, 2017, passing Earth at a minimum distance of almost 51 million km (32 million mi). This will place it well outside the orbit of the Moon, so the odds of it threatening Earth are negligible. But for those keen observers hoping to catch sight of the object, it will be close enough that it might be visible with just a pair of binoculars.
Since its discovery, 2016 WF9 has been of interest to astronomers, mainly because it straddles the already blurry line between asteroids and comets. While its proportions are known – roughly 0.5 to 1 kilometer in diameter (0.3 to 0.6 miles) – its other characteristics have led to some confusion as to where it came from. For one, its appearance (which is quite dark) and its orbit are consistent with what one expects from a comet.
But on the other hand, it lacks the characteristic cloud of dust and gas that comets are known for. As James Bauer, NEOWISE’s Deputy Principal Investigator at JPL, said in a NASA press release:
“2016 WF9 could have cometary origins. This object illustrates that the boundary between asteroids and comets is a blurry one; perhaps over time this object has lost the majority of the volatiles that linger on or just under its surface.”
The other object, C/2016 U1 NEOWISE, was discovered about a month prior to 2016 WF9. Its orbit, which can you see by checking out the 3D Solar System Simulator, takes it from the outer Solar System to within Mercury’s orbit over the course of thousands of years. According to NASA scientists, this object is very clearly a comet, as evidenced by the dust it has been releasing as it gets closer to our Sun.
During the first week of 2017, comet C/2016 U1 NEOWISE is also likely to be visible in the night sky – in this case, in the southeastern sky shortly before dawn (for those looking from the northern hemisphere). It will reach its closest point to the Sun on January 14th (where it will be passing within Mercury’s orbit) before heading back out towards the outer Solar System.
Once again, it is believed that comet-hunters should be able to see it, though that is open to question. Paul Chodas, the manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory, thinks that this object “has a good chance of becoming visible through a good pair of binoculars, although we can’t be sure because a comet’s brightness is notoriously unpredictable.”
In any case, NASA will be continuing to monitor 2016 WF9 to see if they can’t sort out what it is. Should it prove to be a comet, it would be the tenth discovered by NEOWISE since it was reactivated in December of 2013. If it turns out to be an asteroid, it would be the one-hundredth discovered since its reactivation.
As of November 2016, the orbital telescope has conducted over 562,000 infrared measurements have been made of 24,024 different solar system objects, including 613 NEOs and 110 comets. It has also been responsible for discovering 249 new near-Earth objects and comets, as well as more than 34,000 asteroids during its original mission.
At present, NEOWISE’s science team is currently reprocessing all its primary mission data to extend the search for asteroids and comets. It is hoped that by taking advantage of the latest in photometric and astrometric calibrations, they will be able to push the limits of what the telescope can detect, thereby adding many more minor planets and objects to its suite of discoveries.
And be sure to enjoy this video, detailing the first two years of asteroid data collected by the NEOWISE mission:
Of the more than 600,000 known asteroids in our Solar System, almost 10 000 are known as Near-Earth Objects (NEOs). These are asteroids or comets whose orbits bring them close to Earth’s, and which could potentially collide with us at some point in the future. As such, monitoring these objects is a vital part of NASA’s ongoing efforts in space. One such mission is NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE), which has been active since December 2013.
And now, after two years of study, the information gathered by the mission is being released to the public. This included, most recently, NEOWISE’s second year of survey data, which accounted for 72 previously unknown objects that orbit near to our planet. Of these, eight were classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth.
In February of 2014, NASA put out the call for submissions for the thirteenth mission of their Discovery Program. In keeping with the program’s goal of mounting low-cost, highly focused missions to explore the Solar System, the latest program is focused on missions that look beyond Mars to new research goals. On September 30th, 2015, five semifinalists were announced, which included proposals for sending probes back to Venus, to sending orbiters to study asteroids and Near-Earth Objects.
Among the proposed NEO missions is the Near Earth Object Camera, or NEOCam. Consisting of a space-based infrared telescope designed to survey the Solar System for potentially hazardous asteroids, the NEOCam would be responsible for discovering and characterizing ten times more near-Earth objects than all NEOs that have discovered to date.
If deployed, NEOCam will begin discovering approximately one million asteroids in the Main Belt and thousands of comets in the course of its 4 year mission. However, the primary scientific goal of NEOCam is to discover and characterize over two-thirds of the asteroids that are larger that 140 meters, since it is possible some of these might pose a threat to Earth someday.
The technical term is Potentially Hazardous Objects (PHO), and it applies to near-Earth asteroids/comets that have an orbit that will allow them to make close approaches to Earth. And measuring more than 140 meters in diameter, they are of sufficient size that they could cause significant regional damage if they struck Earth.
In fact, a study conducted in 2010 through the Imperial College of London and Purdue University found that an asteroid measuring 50-meters across with a density of 2.6 grams per cubic centimeter and a speed of 12.7 kps could generate 2.9 Megatons of airburst energy once it passed through our atmosphere. To put that in perspective, that’s the equivalent of about nine W87 thermonuclear warheads!
By comparison, the meteor that appeared over the small Russian community of Chelyabinsk in 2013 measured only 20 meters across. Nevertheless, the explosive airbust caused by it entering our atmosphere generated only 500 kilotons of energy, creating a zone of destruction tens of kilometers wide and injuring 1,491 people. One can imagine without much effort how much worse it would have been had the explosion been six times as big!
What’s more, as of August 1st, 2015, NASA has listed a total of 1,605 potentially hazardous asteroids and 85 near-Earth comets. Among these, there are 154 PHAs believed to be larger than one kilometer in diameter. This represents a tenfold increase in discoveries since the end of the 1990s, which is due to several astronomical surveys being performed (as well as improvements in detection methods) over the past two and a half decades.
As a result, monitoring and characterizing which of these objects is likely to pose a threat to Earth in the future has been a scientific priority in recent years. It is also why the U.S. Congress passed the “George E. Brown, Jr. Near-Earth Object Survey Act” in 2005. Also known as the “NASA Authorization Act of 2005”, this Act of Congress mandated that NASA identify 90% of all NEOs that could pose a threat to Earth.
If deployed, NEOCam will monitor NEOs from the Earth–Sun L1 Lagrange point, allowing it to look close to the Sun and see objects inside Earth’s orbit. To this, NEOCam will rely on a single scientific instrument: a 50 cm diameter telescope that operates at two heat-sensing infrared wavelengths, to detect the even the dark asteroids that are hardest to find.
By using two heat-sensitive infrared imaging channels, NEOCam can also make accurate measurements of NEO and gain valuable information about their sizes, composition, shapes, rotational states, and orbits. As Dr. Amy Mainzer, the Principal Investigator of the NEOCam mission, explained:
“Everyone wants to know about asteroids hitting the Earth; NEOCam is designed to tackle this issue. We expect that NEOCam will discover about ten times more asteroids than are currently known, plus millions of asteroids in the main belt between Mars and Jupiter. By conducting a comprehensive asteroid survey, NEOCam will address three needs: planetary defense, understanding the origins and evolution of our solar system, and finding new destinations for future exploration.”
Dr. Mainzer is no stranger to infrared imaging for the sake of space exploration. In addition to being the Principal Investigator on this mission and a member of the Jet Propulsion Laboratory, she is also the Deputy Project Scientist for the Wide-field Infrared Survey Explorer (WISE) and the Principal Investigator for the NEOWISE project to study minor planets.
She has also appeared many times on the History Channel series The Universe, the documentary featurette “Stellar Cartography: On Earth”, and serves as the science consultant and host for the live-action PBS Kids series Ready Jet Go!, which will be debuting in the winter of 2016. Under her direction, the NEOCam mission will also study the origin and ultimate fate of our solar system’s asteroids, and finding the most suitable NEO targets for future exploration by robots and humans.
Proposals for NEOCam have been submitted a total of three times to the NASA Discovery Program – in 2006, 2010, and 2015, respectively. In 2010, NEOCam was selected to receive technology development funding to design and test new detectors optimized for asteroid and comet detection and discovery. However, the mission was ultimately overruled in favor of the Mars InSight Lander, which is scheduled for launch in 2016.
As one of the semifinalists for Discovery Mission 13, the NEOCam mission has received $3 million for year-long studies to lay out detailed mission plans and reduce risks. In September of 2016, one or two finalist will be selected to receive the program’s budget of $450 million (minus the cost of a launch vehicle and mission operations), and will launch in 2020 at the earliest.
In related news, NASA has confirmed that the asteroid known as 86666 (2000 FL10) will be passing Earth tomorrow. No need to worry, though. At its closest approach, the asteroid will still be at a distance of 892,577 km (554,000 mi) from Earth. Still, every passing rock underlines the need for knowing more about NEOs and where they might be headed one day!
Comet C/2012 K1 PanSTARRS, one of the most dependable comets of 2014, may put on its encore performance over the coming weeks for southern hemisphere observers.
First, the story thus far. Discovered as a +19th magnitude smudge along the borders of the constellations Ophiuchus and Hercules in mid-May 2012 courtesy of the Panoramic Survey Telescope And Rapid Response System (PanSTARRS) based atop Haleakala on the Hawaiian island of Maui, astronomers soon realized that comet C/2012 K1 PanSTARRS would be something special.
The comet is approaching the inner solar system on a retrograde, highly-inclined orbit tilted 142 degrees relative the ecliptic. This bizarre orbit also assures that the comet will actually reach opposition twice in 2014 as seen from our earthly vantage point: once on April 15th, and another opposition coming right up on November 7th.
As was the case with comet Hale-Bopp way back in 1997, had C/2012 K1 PanSTARRS arrived six months earlier or later, we would’ve been in for a truly spectacular show, as the comet reached perihelion on August 27th, 2014, only 0.05 A.U.s (4.6 million miles or 7.7 million kilometres) outside the orbit of the Earth! But such a spectacle was not to be… back in ’97, Hale-Bopp’s enormous size — featuring a nucleus estimated 40 to 60 kilometres across — made for a grand show regardless… fast forward to 2014, and the tinier nucleus of K1 PanSTARRS has been relegated to binocular status only.
From here on out, K1 PanSTARRS is headed south “with a bullet” and into memory for most northern hemisphere observers. We spied the comet this morning low to the south near +3rd magnitude Nu Puppis in the pre-dawn sky with our trusty 15×45 binocs from Yuma, Arizona, for what will probably be our last time. This also means that the time to catch a last glimpse of K1 PanSTARRS for northern hemisphere viewers is now. This week sees the comet transiting just 20 degrees above the southern horizon at 3:00 to 4:00 AM local for observers based from latitude 30 degrees north as it crosses the constellation Puppis. The bright star Sirius nearly shares the same position as the comet in right ascension this week, and K1 PanSTARRS sits about 24 degrees south of the Dog Star.
Halloween sees the comet even lower, crossing the southern meridian at only 13 degrees elevation as seen from latitude 30 degrees north. Draw a straight line from Sirius to the south celestial pole around this date to find the comet just 5 degrees to the north of Canopus.
But the show is just beginning for southern hemisphere residents. Observing from the town of Bright Australia, Robert Kaufmann recently noted in a posting on the Yahoo Groups Comet Observer’s message board that the comet currently exhibits a 4’ wide coma shining at about magnitude +7.3 with an elevation of 28 degrees above the horizon on October 25th.
And if the comet holds steady in brightness, it may break the visual threshold and become a naked eye object as seen from a dark sky site in early November.
The comet will be literally “hauling tail” across the constellation Dorado as it nears its second opposition of the year on November 7th, moving about 1.5 degrees a day – 3 times the apparent diameter of the Full Moon – on closest approach.
Currently, the comet has been observed to have an estimated magnitude holding steady at+7 and is predicted to peak at perhaps magnitude +6 early next month. And while it would’ve been great had it arrived 6 months earlier or later, the aforementioned high retrograde inclination of its orbit assured that K1 PanSTARRS was a top performer for both hemispheres in 2014.
Perihelion passage occurred two months ago, but to paraphrase a famous Monty Python skit, Comet K1 PanSTARRS is “not dead yet.” Here are some key observing dates coming right up as the comet gains prominence in the southern hemisphere sky:
(Note that close passages of less than one degree near stars +4th magnitude or brighter only are mentioned).
Oct 31st: Passes closest to Earth, at 0.953 A.U.s distant.
Nov 1st: Crosses into the constellation Pictor.
Nov 2nd: Passes near the +3.8 magnitude star Beta Pictoris.
Nov 6th: Crosses into the constellation Dorado.
Nov 6th: Full Moon occurs, marking the beginning of an unfavorable week for comet hunting.
Nov 7th: The second opposition of the comet for 2014 occurs at 3:00 UT.
Dec 18th: Crosses into the constellation Sculptor.
Dec 22nd: New Moon occurs.
Looking at 2015, K1 PanSTARRS will probably fall back below +10th magnitude by late January. The comet will then head back out into the depths of the outer solar system, its multi-million year orbit only slightly altered by its inner solar system passage down into the ~700,000 year range. What will Earth be like on that far off date? Will human eyes greet the comet once again, and will anyone remember its appearance way back in the mists of time in 2014? All thoughts to ponder as we bid fair well to Comet C/2012 K1 PanSTARRS, a fine binocular comet indeed.