NEO NEWS (27 Oct 2015) Halloween Asteroid, AIDA Mission, Mass Extinctions
ROBERT FARQUHAR (1932-2015). Bob Farquhar died on October 18. He was a genius both in calculating spacecraft orbits and in convincing NASA to support his strategies to get far more out of planetary missions than had originally been planned. Among his contributions were the NEAR-Shoemaker mission to EROS and the extended ISEE mission. Keith Cowing called him “a steely-eyed missile man and a genuine space cowboy who always knew exactly how to get NASA to do what it needed to do – even if NASA did not know it at the time.”
NASA SPOTS THE ‘GREAT PUMPKIN’:
HALLOWEEN ASTEROID A TREAT FOR RADAR ASTRONOMERS
NASA scientists are tracking the upcoming Halloween flyby of asteroid 2015 TB145 with several optical observatories and the radar capabilities of the agency’s Deep Space Network at Goldstone, California. The asteroid will fly past Earth at a safe distance slightly farther than the Moon’s orbit on Oct. 31 at 10:05 a.m. PDT (1:05 p.m. EDT). Scientists are treating the flyby of the estimated 400-meter asteroid as a science target of opportunity, allowing instruments on “spacecraft Earth” to scan it during the close pass.
Asteroid 2015 TB145 was discovered on Oct. 10, 2015, by the University of Hawaii’s Pan-STARRS-1 (Panoramic Survey Telescope and Rapid Response System) on Haleakala, Maui, part of the NASA-funded Near-Earth Object Observation (NEOO) Program. According to the catalog of near-Earth objects (NEOs) kept by the Minor Planet Center, this is the closest currently known approach by an object this large until asteroid 1999 AN10, at about 800 meters in size, approaches at about 1 lunar distance in August 2027.
“The trajectory of 2015 TB145 is well understood,” said Paul Chodas, manager of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory, Pasadena, California. “At the point of closest approach, it will be no closer than about 480,000 kilometers or 1.3 lunar distances.”
“The close approach of 2015 TB145, coupled with its size, suggests it will be one of the best asteroids for radar imaging we’ll see for several years,” said Lance Benner, of JPL, who leads NASA’s asteroid radar research program. “We plan to test a new capability to obtain radar images with two-meter resolution for the first time and hope to see unprecedented levels of detail.”
“The asteroid’s orbit is very oblong with a high inclination,” said Benner. “Such a unique orbit, along with its high encounter velocity — about 35 kilometers per second — raises the question of whether it may be some type of comet. If so, then this would be the first time that the Goldstone radar has imaged a comet from such a close distance.”
ADDED COMMENT BY PAUL CHODAS
We got out early on this story, partly because it will be a great radar target. I’ve already been fielding questions. One key question is why the asteroid wasn’t discovered until now. The short answer is that the asteroid follows an orbit that makes it difficult to detect.
The orbit is both eccentric and inclined, and the asteroid spends most of its time far from the Earth and well below the plane of the ecliptic. In fact it spends less than 5% of its time north of the ecliptic, and all of that inside the Earth’s orbit.
Furthermore, the asteroid’s orbital period is 3.07 years, so that each dive into the inner solar system only advances 0.07 of the way around the Earth’s orbit, relative to our planet. It has been about 25 years since the last time this asteroid was easily detectable. We didn’t have very complete coverage of the sky 25 years ago, especially at southerly ecliptic latitudes.
Innevitably, the tabloids are raising the possibility of a catastrophic collision. NASA does call this a “potentially hazardous” asteroid, so we are partly to blame. Here is a thoughtful discussion of this issue.
ASTEROID TO STRIKE EARTH ON HALLOWEEN: SCAREMONGERING, OR SCARY FACT? By Hamilton Nolan: science10/21/15
Here is what everyone agrees on: this Halloween, a “massive” asteroid will pass close to earth at “unusually” high speeds. Will it kill us? Well, that is the question.
Certainly, when we are confronted with news of a looming date with an asteroid “the size of a football stadium,” the question that is foremost in the minds of the public, as well as media representatives such as ourselves who exist to serve the public, is: Will this asteroid, which is moving at a speed of more than 78,000 miles per hour, crash directly into Earth, setting off a calamitous global extinction event of the sort that wiped out the dinosaurs long ago? After all, if an asteroid is merely going to pass within 300,000 miles of our planet, as so many of the “experts” hasten to reassure us, then it makes us wonder why we should pay any attention to the asteroid’s fly-by at all. I may not be a credentialed astronomer or famous planetary scientist, but I do have a dose of common sense. So I ask myself: if this asteroid will not get within 300,000 miles of us, why are all these media outlets publishing stories about it? What difference does it make to readers if a big rock flies by so far away that we can’t even see it? Why so much hubbub?
I may not be a NASA “insider,” but I do feel a responsibility to use my media platform to keep readers appraised of important—and potentially life-altering—news developments. And so I am simply raising to you the unavoidable question: … Will we face our doom, with ghoulish propriety, on Halloween, the night when we celebrate Satan’s power? It is simply dishonest not to confront this question, based upon the strong circumstantial evidence at hand. I am not here to scare anyone unnecessarily; nor am I here to participate in a vast coverup. I am here only to ask why we are hearing so much about this huge asteroid, if there is no chance that it will kill us all….
I am just one respected journalist. I do not seek to cause alarm. I only want you all to use your own critical faculties to evaluate the “official” story of what’s happening. I’m obligated by professional ethics to report to you that NASA says “There is no asteroid threatening earth.” But let’s dig deeper. In fact, NASA’s statement is about claims “that an asteroid will impact Earth, sometime between Sept. 15 and 28, 2015.” A NASA scientist says, trickily, “There is no scientific basis — not one shred of evidence — that an asteroid or any other celestial object will impact Earth on those dates.”
Will an asteroid impact Earth on Halloween though? I don’t even want to know. Do you? …. Happy Halloween—I hope.
NASA AND ESA TO SEND SPACECRAFT TO SMALL ASTEROID DIDYMOON TO KNOCK IT OFF ITS COURSE
International Business Times – Fri, Oct 2, 2015
The European Space Agency (ESA) and NASA have announced that, as part of a joint mission, they will send a spacecraft towards a small asteroid in a bid to knock it off its course. The two continental forces are doing this as a practice run to prepare for any potential asteroids that could come hurtling towards Earth.
The AIDA (Asteroid Impact & Deflection Assessment) project will involve sending a spacecraft to a small asteroid – measuring around 160m wide – named Didymoon. The relatively small space rock orbits a much larger asteroid called Didymos. Another spacecraft will join the “nudger” as it looks to monitor the effects and to see if it is successful. They will be launched in October 2020 and are expected to collide with the asteroid in May 2022.
Dr Patrick Michel, lead investigator for the ESA, told scientists at the European Planetary Science Congress (EPSC) in Nantes, France: “To protect Earth from potentially hazardous impacts, we need to understand asteroids much better – what they are made of, their structure, origins and how they respond to collisions.
“AIDA will be the first mission to study an asteroid binary system, as well as the first to test whether we can deflect an asteroid through an impact with a spacecraft. The European part of the mission… will study the structure of Didymoon and the orbit and rotation of the binary system, providing clues to its origin and evolution.”
ASTEROID SHOWERS LINKED TO MASS EXTINCTIONS
Press Release: Scientists find links between comet and asteroid showers and recurring mass extinctions of life on Earth, including the demise of the dinosaurs. Mass extinctions occurring over the past 260 million years were likely caused by comet and asteroid showers, scientists conclude in a new study published yesterday (October 20) in Monthly Notices of the Royal Astronomical Society.
For more than 30 years, scientists have argued about a controversial hypothesis relating to periodic mass extinctions and impact craters – caused by comet and asteroid showers – on Earth.
In their new paper, Michael Rampino, a New York University geologist, and Ken Caldeira, a scientist in the Carnegie Institution’s Department of Global Ecology, offer new support linking the age of these craters with recurring mass extinctions of life, including the demise of the dinosaurs. Specifically, they show a cyclical pattern over the studied period, with both impacts and extinction events taking place every 26 million years.
This cycle has been linked to periodic motion of the sun and planets through the dense mid-plane of our galaxy. Scientists have theorized that gravitational perturbations of the distant Oort comet cloud that surrounds the sun lead to periodic comet showers in the inner solar system, where some comets strike the Earth.
To test their hypothesis, Rampino and Caldeira performed time-series analyzes of impacts and extinctions using newly available data offering more accurate age estimates. Rampino said: The correlation between the formation of these impacts and extinction events over the past 260 million years is striking and suggests a cause-and-effect relationship.
Specifically, he and Caldeira found that six mass extinctions of life during the studied period correlate with times of enhanced impact cratering on Earth. One of the craters considered in the study is the large (180 km diameter) Chicxulub impact structure in the Yucatan, which dates to about 65 million years ago – the time of a great mass extinction that included the dinosaurs.
Moreover, they add, five out of the six largest impact craters of the last 260 million years on Earth correlate with mass extinction events. Rampino said: This cosmic cycle of death and destruction has without a doubt affected the history of life on our planet.
The Abstract says: A digital circular spectral analysis of 37 crater ages (ranging in age from 15 to 254 Myr ago) yielded evidence for a significant 25.8 ± 0.6 Myr cycle. Using the same method, we found a significant 27.0 ± 0.7 Myr cycle in the dates of the eight recognized marine extinction events over the same period. The cycles detected in impacts and extinctions have a similar phase. The impact crater dataset shows 11 apparent peaks in the last 260 Myr, at least 5 of which correlate closely with significant extinction peaks. These results suggest that the hypothesis of periodic impacts and extinction events is still viable.
COMMENT FROM MORRISON: It is unfortunate that the writers of the press release refer to “comet and asteroid showers”, and this phrase has appeared in all the reports. Comet showers are possible because some external tidal disturbance, as by a passing star, might dislodge many comets from the Oort Comet Cloud. I can think of no way a similar mechanism could send many asteroids from the Asteroid Belt plunging into the inner solar system.
NEO News (now in its twentieth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.