Comet NEOWISE...

Comet NEOWISE over Mount Hood on July 11, 2020. Credit: Kevin Morefield Getty Images

Topics: Astronomy, Astrophysics, Comets

Comet NEOWISE has been entertaining space enthusiasts across the Northern Hemisphere. Although its official name is C/2020 F3, the comet has been dubbed NEOWISE after the Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) space telescope that first noticed it earlier this year. This “icy snowball” with a gassy tail made its closest approach to the sun on July 3 and is now heading back from whence it came: the far reaches of the outer solar system. Its long, looping orbit around our star ensures that after passing closest to Earth on July 22, Comet NEOWISE will not return for some 6,800 years.

Even though the comet is now bright enough to observe with unaided eyes, inexperienced stargazers might have trouble knowing when and where to look. Scientific American spoke to Jackie Faherty, an astronomer at the American Museum of Natural History in New York City, for observing tips and a better appreciation of why comets are so special.

How does one prepare to watch Comet NEOWISE with the naked eye?

Find the darkest possible swath of sky and make sure your eyes are adjusted so that you give yourself the best possible opportunity to see faint objects. It means: don’t just walk outside after staring at lights or screens and expect to see [the comet] really well. You need 15 minutes or so to adjust your eyes, so that your pupils are adjusted, and they’re used to seeing fainter things. It’s the same as walking into a dark room, and everybody knows that [you] can’t see [things] first—and then, all of a sudden, you start seeing things. You need to do the same thing when you walk outside. And use the Comet NEOWISE app developed by astrophysicist Hanno Rein of University of Toronto Scarborough to see exactly where it is, so that you know what direction you need to look. And then the key would be to find yourself a place that is the darkest possible, that [has] no lights.

The Best Way to Watch Comet NEOWISE, Wherever You Are, Karen Kwon, Scientific American

No Fooling...

Topics: Astronomy, Astrophysics, Comets, NASA

A comet whose identity took nearly 100 years to pin down is making its closest approach to Earth today (April 1), just in time for April Fools' Day, but this is no cosmic prank. It is the comet's closest Earth encounter in more than 50 years, and maybe more than a century, NASA officials said.

Comet 41P/Tuttle-Giacobini-Kresák is named after its three discoverers —Horace Tuttle, Michael Giacobini and L'ubor Kresák — who tracked the comet separately over nearly a century.

Tuttle first spotted the comet in 1858, when 41P was first identified as a sun-orbiting (or periodic) comet, NASA officials wrote, citing the Cometagraphy website by Gary Kronk. But the length of the comet's orbit was unknown at the time. Comet 41P was rediscovered in 1907 by Giacobini, but still not tied to the object seen by Tuttle in 1858.

Another astronomer, Andrew Crommelin, later linked the two observations by Tuttle and Giacobini and predicted Comet 41P would return in 1928 and 1934, but the object went unseen, according to Cometography. It wasn't until 1951, when Kresák spotted the comet and linked it with the earlier observations, that Comet 41P identity was officially pinned down.

Space.com: April Fools' Comet Passes by Earth, Took Nearly a Century to Identify
Tariq Malik, Space.com Managing Editor

Rosetta's MIDAS...

Courtesy: http://blogs.esa.int/rosetta/2014/03/26/introducing-midas-rosettas-micro-imaging-dust-analysis-system/

Topics: Astrophysics, Comets, ESA, NASA, Rosetta, Space Exploration, Women in Science

There is a movie coming out in 2017 called "Hidden Figures" about the African American women that were "computers" as they were all called at the time. Behind the scenes and out of notice (purposely) from the public eye, these scientists were responsible for mankind getting to the moon, despite what your conspiracy provocateur uncle spouts around the dinner table at Thanksgiving.

Dr. Claudia Alexander was a project scientist on the American portion of the international Rosetta mission. She sadly lost her battle with breast cancer last year. I always try to highlight such achievements since its obvious from a societal structural sense, negative stereotypes are often forwarded to maintain an inane "status quo" while simultaneously complaining about "bootstraps." I salute Dr. Alexander, a modern Hidden Figure in Science that paved the way for new discoveries by humankind.

Thanks to in situ measurements from MIDAS (the Micro-Imaging Dust Analysis System) on-board the Rosetta spacecraft, researchers have now found out more about the structure of the dust particles on comet 67P/Churyumov-Gerasimenko. The particles are made up of aggregates and cover a range of sizes – from tens of microns to a few hundred nanometres. They also appear to have formed from the hierarchical assembly of smaller constituents and come in a range of shapes, from single grains to larger, porous aggregated particles with some dust grains being elongated. The study could shed more light on the processes that occurred when our Solar System formed nearly five billion years ago.

Planetary systems like our own Solar System started out as dust particles in protoplanetary nebulae – clouds of gas and dust that gave rise to stars and planets. The particles collided and agglomerated to form planetesimals – the building blocks of planets. Comets are leftover planetesimals and are made of ice and dust particles. They range in size from a few hundreds of metres to ten of kilometres and are mainly found on the outskirts of the Solar Systems, far from damaging radiation, high temperatures and collisions with other objects.

Nanotech Web:
Rosetta’s MIDAS analyses cometary dust particles, Belle Dumé

Heavenly Gates...

Topics: Astrophysics, Comets, Diversity, Diversity in Science, Space Exploration, Rosetta, Women in Science

Yesterday was "Back to the Future, Part II" day. I saw a lot of commentary about how far we've come in 30 years. Interestingly not only did I not comment on it, I don't really recall seeing the second movie! I saw the first and third. I guess I'll have to rent it to catch up. We don't have flying cars or hover boards, but we seem to have a plethora of "Biff" personalities. I'll let you interpret...

This also happened yesterday, which didn't get a lot of notice. I don't expect it will, but if our priorities were actually calibrated to regard important people doing important things other than athletes, bombastic public characters, rappers and "reality shows"...it would.

The C. Alexander Gate, located on the smaller lobe of Comet 67P/C-G, has been named for Claudia J. Alexander, a U.S. Rosetta project scientist. Alexander passed away on July 11, 2015, after a 10-year battle with breast cancer. She was 56.

Alexander earned a bachelor's degree in geophysics from the University of California, Berkeley, and a master's degree in geophysics and space physics from the University of California, Los Angeles. She went on to earn her doctorate degree in atmospheric, oceanic and space sciences from the University of Michigan, Ann Arbor. She began working at NASA's Jet Propulsion Laboratory in California before completing her doctorate. At the relatively young age of 40, she served as project manager for NASA's Galileo mission in 2000.

Alexander strove to inspire young people, writing children's books on science and mentoring young African-American girls. She also wrote "steampunk" science-fiction short stories.

The A. Coradini Gate, located on the larger lobe of the comet, was dedicated to Angioletta Coradini, the former principal investigator of Rosetta's VIRTIS instrument. Coradini passed away in September 2011 after a year-long battle with cancer. She was 65.

Coradini earned her master's degree in physics at the University of Rome, where she also earned her doctorate degree. She worked for the National Research Council of Italy before moving on to the National Astrophysics Institute of Italy. She led the Italian team for the Cassini VIMS visual channel. She worked on NASA's Dawn mission team, which explored the asteroid Vesta and is presently in orbit around the dwarf planet Ceres.

"Angioletta was one of the world-recognized leading experts in the Planetary Sciences, with varied interests ranging from minor bodies to outer planets and theoretical work on the formation of our solar system," said a tribute posted on the American Astronomical Society website. "She made fundamental contributions in all these domains."

Space.com: Rosetta Team Names Comet Features for Lost Colleagues
Nola Taylor Redd

Our Loss, the Universe's Gain...

Claudia Alexander (1959–2015)

Topics: Comets, Diversity, Diversity in Science, Rosetta, Space Exploration, STEM, Women in Science

As a research scientist, she inspired a generation, especially young women, to seek careers in science, technology, engineering and math.

This weekend was one of great excitement for the planetary science community as the New Horizons spacecraft moved in on Pluto following decades of hard work. But that optimism took on a somber tone Saturday as news quickly traveled that pioneering scientist Claudia Alexander had died at age 56. Friends and family writing online tributes reported she suffered from breast cancer, but no official cause of death was given.

Alexander was an employee of the Jet Propulsion Laboratory (JPL) and the final project manager for NASA’s Galileo mission. But her public profile rose dramatically last fall due to her duties as project scientist for NASA’s role in the European Space Agency’s Rosetta mission to Comet 67P/Churyumov-Gerasimenko.

"The passing of Claudia Alexander reminds us of how fragile we are as humans but also as scientists how lucky we are to be part of planetary science,” James Green, director of NASA's Planetary Science Division, said in a statement. “She and I constantly talked about comets. Comet Churyumov-Gerasimenko in particular. She was an absolute delight to be with and always had a huge engaging smile when I saw her. It was easy to see that she loved what she was doing. We lost a fantastic colleague and great friend. I will miss her."

Astronomy: Pioneering Rosetta mission scientist Claudia Alexander dead at 56, Eric Betz

Alice's Wonderland...

Image Source: ESA Rosetta Blog

Topics: Astronomy, Astrophysics, Comets, Rosetta, Spectrograph

A close-up of Comet 67P/Churyumov-Gerasimenko by NASA's ultraviolet instrument surprised scientists by revealing that electrons close to the comet's surface—not photons from the Sun as had been believed—cause the rapid breakup of water and carbon dioxide molecules spewing from the surface.

Since last August, the European Space Agency's Rosetta spacecraft has orbited within a hundred miles of the comet in this historic mission. The spectrograph onboard, named Alice, specializes in the far-ultraviolet wavelength band and was developed by Southwest Research Institute (SwRI). Alice examines light the comet is emitting to understand the chemistry of the comet's atmosphere, or coma. A spectrograph is a tool astronomers use to split light into its various colors. Scientists can identify the chemical composition of gases by examining their light spectrum. Alice is the first such far-ultraviolet spectrograph to operate at a comet.

NASA's Alice ultraviolet (UV) spectrograph, seen here during construction, is aboard the European Space Agency's Rosetta spacecraft. Credit: Southwest Research Institute

"The discovery we're reporting is quite unexpected," said Alice instrument Principal Investigator Dr. Alan Stern, an associate vice president in SwRI's Space Science and Engineering Division. "It shows us the value of going to comets to observe them up close, since this discovery simply could not have been made from Earth or Earth's orbit with any existing or planned observatory. And, it is fundamentally transforming our knowledge of comets.

Phys.org: Alice instrument's ultraviolet close-up provides a surprising discovery about comet's atmosphere

Physics 2014...

First Realistic Virtual Universe (see 5 below)

In May cosmologists took the place on the pedestal by releasing the first simulated universe of such a large scale: it simulated 13 billion years of cosmic evolution in a cube with 350 million light year long sides. “Until now, no single simulation was able to reproduce the universe on both large and small scales simultaneously,” said the lead author Mark Vogelsberger.

1. Deepest Image of a Galaxy Cluster (January)
2. NASA Releases First Images Taken by the Curiosity Rover ( February)
3. The Discovery of Gravitational Waves (March), though there's some recent data that cast doubt.
4. NASA’s Exoplanet Discoveries (April)
5. The First Realistic Virtual Universe (May)
6. Hybrid Carbon Nanotube Circuits (June)
7. OCO-2 Launched (July) The OCO-2 will study carbon dioxide concentrations and distributions in the atmosphere.
8. Field Medals and IBM’s Neuromorphic Computer Chip (August)
9. Water Vapour Found on an Exoplanet + India’s First Probe to Mars (September)
10. Nobel Prizes (October), the winners were Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, who were responsible for the development of the efficient blue light diodes.
11. Landing on a Comet (November), the first landing on the surface of a comet performed by the Rosetta spacecraft equipped with Philae landing module.
12. Planck 2014 Results (December)
The newest data suggests that the universe is 13.8 billion years old and is composed of 4.9 percent atomic matter, 26.6 percent dark matter and 68.5 percent dark energy.

Physics Database: Top Physics News of 2014

SETI Talk - Dr. Alexander...

Dr. Claudia Alexander - Geophysics, NASA Project Scientist, APS

Here we have a talk by Claudia Alexander who will explain the science background of some of the mysteries of comets including pros and cons about why we think comets might have brought Earth’s water, concepts regarding missing nitrogen in the outer solar system, and material the comet is made of. Finally Dr Alexander will set the stage for the landing and walk through the 60 hours of time spent on the comet’s surface. The initial findings are summarized as well.

Source: Physics Database

Landing on a Comet...

So, what will we find?

Ice, minerals are sure bets. Hopefully the harpoons they've engineered hold on whatever qualifies as a "surface" on a comet. The fun of science is the unknown; that's the adventure!

The ancient Greek on the Rosetta Stone told archaeologists that it was inscribed by priests honoring the king of Egypt, Ptolemy V, in the second century B.C. More startlingly, the Greek passage announced that the three scripts were all of identical meaning. The artifact thus held the key to solving the riddle of hieroglyphics, a written language that had been "dead" for nearly 2,000 years. Source: The History Channel

It is appropriate that we'll be reaching back in time, perhaps to the dawn of our solar system, a hieroglyphics of radiometric and Carbon-14 dating: back to our very beginnings.

European Space Agency: Live Rosetta Updates

Siding Spring...

It was yesterday. It's perhaps been traveling a million years to this date.

The NASA brief:


NASA: Comets: Siding Spring

Rosetta Encounter...

Image Source: Women in Planetary Science

Dr. Alexander is the Project Scientist for the U.S. portion of the international Rosetta mission. She has also been the Cassini Project Staff Scientist and as the final project manager of the Galileo mission, overseeing its fiery crash into Jupiter. Her scientific interests include gaskinetic theory, theory of gaseous escape from planetary and cometary regoliths, theory of surface bound exospheres, magnetospheric plasma theory (terrestrial and planetary), exobiology, interdiciplinary science, and oxidation / reduction potential of planetary and cometary regoliths. Source: see #P4TC links below.

Watch live streaming video from eurospaceagency at livestream.com

Space.com: Rosetta Probe Arrives at Comet #P4TC links: Rosetta... Rosetta's Stone...

Dark Matter and Dino...

Artist's impression of a comet striking the Earth. (Courtesy: iStock/PaulPaladin)

Two theoretical physicists in the US have made a surprising connection between dinosaur extinction and dark matter. Lisa Randall and Matthew Reece of Harvard University believe that some of this mysterious invisible matter – which makes up 85% of all matter in the universe – could exist in a special form that affects the rate at which comets strike our planet. A comet crashing into Earth about 66 million years ago is one possible reason why these giant creatures died off.

Comets have smashed into Earth throughout its history, creating huge craters and possibly causing mass extinctions, such as that which befell the dinosaurs. Many of these comets come from the Oort cloud, which is a huge halo of small icy objects that surrounds the Sun, out to a distance of about one light year. But rather than being entirely random, there is some evidence that the frequency of comet impacts oscillates on a timescale of about 35 million years.

Although this oscillation is not certain, if it is true, there could be something on that timescale that affects the rate at which comets from the Oort cloud are sent towards Earth. Two possible explanations have been proposed so far. One – dubbed the "nemesis hypothesis" – involves the gravitational pull of an as-yet-undiscovered distant companion star to the Sun. The other involves the oscillating pull of the dense galactic disc as the solar system crosses and re-crosses the plane of the Milky Way.

Physics World: Did dark matter help kill off the dinosaurs?

Retooled Usage...

"If we're to be anything other than smooth dinosaurs who evolve, specialize and die, we need the stars" ... Octavia Butler, Parable of the Talents, 1998

Yesterday's anniversary:

On Feb. 15, 2013, a 65-foot-wide (20 meters) asteroid detonated in the skies over the Russian city of Chelyabinsk, causing millions of dollars of damage and injuring 1,500 people. The dramatic event served as a wake-up call, many scientists say, alerting the world to the dangers posed by the millions of space rocks that reside in Earth's neck of the cosmic woods.

"These types of events are no longer hypothetical," David Kring, of the Lunar and Planetary Institute in Houston, said in December at the annual fall meeting of the American Geophysical Union (AGU) in San Francisco. "We've been up here talking about these types of things for years, but now the entire world understands that they can be real."

Russian Meteor Blast Thrust Asteroid Danger into Spotlight 1 Year Ago Today

Mike Wall, Senior Writer, Space.com

Being a veteran of the era of "duck and cover" (and, the complete knowledge of its uselessness), I am pleased some are thinking at least instead of "Mutually Assured Destruction" (M.A.D.): Mutually Assured Survival.

A possible way to address via retooling:

The most destructive weapon humanity has ever developed could help our species avoid going the way of the dinosaurs.

Pretty much any asteroid that poses a threat to Earth can be blasted out of the heavens using a nuclear bomb, even with warning times of a week or less, say a team of scientists who have been developing the idea.

"We have the solution, using our baseline concept, to be able to mitigate the asteroid-impact threat, with any range of warning," Bong Wie, of Iowa State University, said Feb. 6 at the 2014 NASA Innovative Advanced Concepts (NIAC) meeting at Stanford University.

A very real threat

Wie presented his team's latest findings nearly a year to the day after a previously undetected 65-foot-wide (20 meters) space rock detonated in the skies above the Russian city of Chelyabinsk, injuring 1,500 people.

He and many other researchers regard the Feb. 15, 2013 Russian meteor explosion— which took locals and scientists alike by surprise — as a wake-up call about the threat Earth faces from incoming space rocks.

"A couple of years ago, I had to use the dinosaur example to justify our research," he said, referring to the asteroid impact that wiped out the giant reptiles 65 million years ago. "Now, that's no more — we had this major event."

How Nuclear Bombs Could Save Earth from Killer Asteroids
Mike Wall, Senior Writer, Space.com

Rosetta...

Image Source: Women in Planetary Science

Dr. Alexander is the Project Scientist for the U.S. portion of the international Rosetta mission. She has also been the Cassini Project Staff Scientist and as the final project manager of the Galileo mission, overseeing its fiery crash into Jupiter. Her scientific interests include gaskinetic theory, theory of gaseous escape from planetary and cometary regoliths, theory of surface bound exospheres, magnetospheric plasma theory (terrestrial and planetary), exobiology, interdiciplinary science, and oxidation / reduction potential of planetary and cometary regoliths.

Her most recent publications include:

• C. Alexander, A. Chmielewski, S. Gulkis, P. Weissman, D. Holmes, J. Burch, R. Goldstein, P. Mokashi, S.A. Stern, J. Parker, S. Fuselier, M. Kueppers, A. Accommazzo, “The U.S. Rosetta Project at its second Science Target: Asteroid (21) Lutetia,” IEEE Conference Proceedings, in press.
• C. Alexander, D. Sweetnam, S. Gulkis, P. Weissman, D. Holmes, J. Burch, R. Goldstein, P. Mokashi, J. Parker, S. Fuselier, L. McFadden, “The U.S. Rosetta Project at its first Science Target: Asteroid (2867) Steins,” IEEE Conference Proceedings, 2010.
• C. Alexander, R. Carlson, G. Consolmagno, D. Morrison, 400 Years of Discovery at Europa, Europa, Pappalardo, McKinnon, Khurana eds., University of Arizona Press, 2009.

2014, Rosetta will enter orbit around comet 67P/Churyumov-Gerasimenkoand land a probe on it, two firsts.

Rosetta’s goal is to learn the primordial story a comet tells as it gloriously falls to pieces.

Comets are primitive leftovers from our solar system's 'construction' about 4.5 billion years ago. Because they spend much of their time in the deep freeze of the outer solar system, comets are well preserved—a gold mine for astronomers who want to know what conditions were like back “in the beginning.”

NASA Science News: Mission to Land on a Comet
European Space Agency: Rosetta