A video of recent public lecture at the SETI Institute giving an overview of the exoplanet discoveries of the Kepler space telescope: The Era of Exoplanets Has Arrived – Jeff Coughlin & Geert Barentsen (SETI Talk 2017) –
NASA’s Kepler space telescope was launched in 2009 and measured the brightness of 200,000 stars at unprecedented precision for over four years, with the prime mission goal of detecting Earth-sized exoplanets. Now after another four, Kepler’s final planet catalog is complete — over 4,000 planet candidates have been found, with 50 of them possibly rocky and capable of having liquid water. For the first time in human history, we can calculate how common planets the same size and temperature as Earth are, a key component to SETI’s goal of figuring out how common life may be in the universe.
The K2 mission began three years ago, and uses the Kepler spacecraft to stare at many different parts of the sky for 80 days at a time. A broad portion of the Astronomical community chooses what targets to observe, resulting in a wide variety of science, including supernovae, galaxies, stars, and of course exoplanets. K2 has found over 300 confirmed exoplanets and an additional 500 candidates. Some of these are likely to be habitable, and many of them are prime targets to be observed by future missions, such as the James Webb space telescope. We’ll discuss what we may learn about these worlds over the next few decades, and what future missions are being planned to find planets to which our descendants may one day travel.
If you could fly aboard NASA’s Dawn spacecraft, the surface of dwarf planet Ceres would generally look quite dark, but with notable exceptions. These exceptions are the hundreds of bright areas that stand out in images Dawn has returned. Now, scientists have a better sense of how these reflective areas formed and changed over time — processes indicative of an active, evolving world.
“The mysterious bright spots on Ceres, which have captivated both the Dawn science team and the public, reveal evidence of Ceres’ past subsurface ocean, and indicate that, far from being a dead world, Ceres is surprisingly active. Geological processes created these bright areas and may still be changing the face of Ceres today,”
said Carol Raymond, deputy principal investigator of the Dawn mission, based at NASA’s Jet Propulsion Laboratory in Pasadena, California. Raymond and colleagues presented the latest results about the bright areas at the American Geophysical Union meeting in New Orleans on Tuesday, Dec. 12.
Different Kinds of Bright Areas
Since Dawn arrived in orbit at Ceres in March 2015, scientists have located more than 300 bright areas on Ceres. A new study in the journal Icarus, led by Nathan Stein, a doctoral researcher at Caltech in Pasadena, California, divides Ceres’ features into four categories.
The bright areas of Occator Crater — Cerealia Facula in the center and Vinalia Faculae to the side — are examples of bright material found on crater floors on Ceres. This is a simulated perspective view. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI › Full image and caption
The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater, which hosts two prominent bright areas. Cerealia Facula, in the center of the crater, consists of bright material covering a 6-mile-wide (10-kilometer-wide) pit, within which sits a small dome. East of the center is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright material in Occator Crater is made of salt-rich material, which was likely once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye.
More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies likely exposed bright material that was already in the subsurface or had formed in a previous impact event.
Separately, in the third category, bright material can be found in the material ejected when craters were formed.
The mountain Ahuna Mons gets its own fourth category — the one instance on Ceres where bright material is unaffiliated with any impact crater. This likely cryovolcano, a volcano formed by the gradual accumulation of thick, slowly flowing icy materials, has prominent bright streaks on its flanks.
Over hundreds of millions of years, bright material has mixed with the dark material that forms the bulk of Ceres’ surface, as well as debris ejected during impacts. That means billions of years ago, when Ceres experienced more impacts, the dwarf planet’s surface likely would have been peppered with thousands of bright areas.
“Previous research has shown that the bright material is made of salts, and we think subsurface fluid activity transported it to the surface to form some of the bright spots,” Stein said.
The Case of Occator
Why do the different bright areas of Occator seem so distinct from one another? Lynnae Quick, a planetary geologist at the Smithsonian Institution in Washington, has been delving into this question.
The leading explanation for what happened at Occator is that it could have had, at least in the recent past, a reservoir of salty water beneath it. Vinalia Faculae, the diffuse bright regions to the northeast of the crater’s central dome, could have formed from a fluid driven to the surface by a small amount of gas, similar to champagne surging out of its bottle when the cork is removed.
Evidence of landslides on Ceres.
In the case of the Vinalia Faculae, the dissolved gas could have been a volatile substance such as water vapor, carbon dioxide, methane or ammonia. Volatile-rich salty water could have been brought close to Ceres’ surface through fractures that connected to the briny reservoir beneath Occator. The lower pressure at Ceres’ surface would have caused the fluid to boil off as a vapor. Where fractures reached the surface, this vapor could escape energetically, carrying with it ice and salt particles and depositing them on the surface.
Cerealia Facula must have formed in a somewhat different process, given that it is more elevated and brighter than Vinalia Faculae. The material at Cerealia may have been more like an icy lava, seeping up through the fractures and swelling into a dome. Intermittent phases of boiling, similar to what happened when Vinalia Faculae formed, may have occurred during this process, littering the surface with ice and salt particles that formed the Cerealia bright spot.
Quick’s analyses do not depend on the initial impact that formed Occator. However, the current thinking among Dawn scientists is that when a large body slammed into Ceres, excavating the 57-mile-wide (92-kilometer-wide) crater, the impact may have also created fractures through which liquid later emerged.
“We also see fractures on other solar system bodies, such as Jupiter’s icy moon Europa,” Quick said. “The fractures on Europa are more widespread than the fractures we see at Occator. However, processes related to liquid reservoirs that might exist beneath Europa’s cracks today could be used as a comparison for what may have happened at Occator in the past.”
As Dawn continues the final phase of its mission, in which it will descend to lower altitudes than ever before, scientists will continue learning about the origins of the bright material on Ceres and what gave rise to the enigmatic features in Occator.
The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: https://dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites:
1. Monday, Dec. 11, 2017: 2-3:30 pm PST (4-5:30 pm CST, 5-6:30 pm EST): We welcome back Dr. Richard Obousy, theoretical physicist. Our guest will be discussing interstellar flight, advanced propulsion and much more. I suggest you watch his recent talk at the 2017 Starship Congress from early August. Just Google his name and the 2017 Starship Congress to see the video of his talk.
2. Tuesday, Dec. 12, 2017: 7-8:30 pm PST, 10-11:30 pm EST, 9-10:30 pm CST: We welcome Christopher Richins of RBC Signals. This is a commercial company providing satellite ground service and communications to small sats and others.
3. Wednesday, Dec. 13, 2017: Hotel Mars. See Upcoming Show Menu and the website newsletter for details. Hotel Mars is pre-recorded by John Batchelor. It is archived on The Space Show site after John posts it on his website.
4. Friday, Dec. 15, 2017; 9:30 am -11 am PST, (12:30 -2 pm EST; 11:30 am -1 pm CST) We welcome Dr. Robert Reynolds, research scientist at the Mortality Institute. He recently completed a thorough study and evaluation, factually based, on heart disease among the Apollo lunar astronauts. His study is titled “Mortality due to Cardiovascular Disease Among Apollo Lunar Astronauts“. See the archive page for this show as the link to his paper is posted there for your review. There is no firewall for the paper at this time but that will change in the near future so I suggest you download the paper sooner, not later.
5. Sunday, Dec. 17, 2017: 12-1:30 pm PST; 2-4:30 pm EST; 2-3:30 pm CST. Welcome to OPEN LINES. .All callers welcome. We talk about the topics you want to discuss. This will be the last Open Lines show for the year!
Scientists around the world are increasingly using satellite technology to study life on earth. Small, inexpensive transponders attached to animals track their movement and interaction with humans, helping scientists and activists protect endangered species. Oceana, an international organization dedicated to the protection and restoration of the world’s oceans, teamed with shark researchers to study the fishing industry’s impact on one shark species. VOA’s George Putic reports.
Oceana created Global Fishing Watch to use satellite data to map fishing activities around the world. From their collection of videos, here is a sampling of three:
I recently posted an item about the “new” sci-fi novel Pioneer by Robert Zimmerman. While Bob is best known as a space historian and journalist, he produced this work of fiction back in 1982 when he was just starting out on his writing career. He set it aside after he had trouble finding a publisher. He came across the transcript in his files this year and decided it was worth releasing.
I’m glad he made it available. I finally had a chance to read it (always way behind on my reading) and wanted to say I really enjoyed it. The plot was laid out previously so I’ll just point out some aspects of the story and Solar Sci-Fi scenario that I found particularly interesting.
One of the reasons Bob released Pioneer was because of its depiction of a solar system where commercial ventures are prevalent and settlements on Mars and the Moon are being established. This fits well with what we see today with entrepreneurial companies like SpaceX and Blue Origin leading the way in innovations that are making access to space affordable and companies like OneWeb, Planet, and NanoRacks creating new space services and products.
However, the time frame of the book is not the early 21st Century but the late 22nd Century. Perhaps it was a symptom of those pessimistic years just a decade or so after the shutdown of Apollo that Bob could not see such ambitious space progress happening until a couple of centuries had passed. With Elon Musk planning Mars settlements and Jeff Bezo pushing for millions of people living and working in space, a grand expansion of life out into the solar system may happen sooner rather than later.
The technology depicted in the novel is also interesting. The spaceships in Pioneer have propulsion systems that can get the crews to distant parts of the solar system but not very quickly. Missions to the asteroids and outer planets take years to complete. This is a more realistic, down-to-earth scenario, so to speak, than warp drives sending ships to this or that star in days. It’s similar to what we see with deep space probes like Cassini, New Horizons, and Juno. However, it’s also a bit on the pessimistic side. Already there are credible fusion propulsion projects underway (e.g. see here and here) that offer major improvements over chemical propulsion. Perhaps in a coupe of decades, and certainly by the 22nd Century, most parts of the solar system should be accessible in months rather than years.
Bob has mentioned that he greatly under-estimated the rapid advances in micro-electronics and computers. I noticed in Pioneer there is also a lot of cable-handling for communications where today we would use wireless routers.
A writer of a “hard sci-fi” story must decide, though, what technologies will have “futuristic” capabilities and what will be similar to current tech. If everything is depicted as hyper-advanced, then the story may seem too magical, too untethered to reality for the reader to take seriously. It also becomes difficult to create a plot that has hurdles for the characters and their super-tech hardware to struggle against and overcome.
For example, if Bob’s characters had used a computer search tool that instantly returned answers extracted from humanity’s vast storehouse of knowledge, I expect many readers in 1982 would have scoffed. Today we take our browser search tools far too much for granted. They are really as wondrous as anything Merlin ever did in Camelot.
Ultimately, a novel in any genre needs interesting characters in a believable setting and a captivating plot. Pioneer has those things even if it doesn’t have Google.
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One of Bob’s best known historical books isGenesis: The Story of Apollo 8, which describes the first time humans left earth’s realm and orbited a distant celestial orb.
A reader points me to a new book on the same mission by Jeffery Kluger: Apollo 8: The Thrilling Story of the First Mission to the Moon. Kluger talks in the following video about why Apollo 8 ranks with 11 and 13 as the key missions of the Apollo program:
, which describes the first time humans left earth’s realm and orbited a distant celestial orb.