NASA's astronaut twins, Scott Kelly (l) and Mark Kelly (r). Image: NASA
In 1996, something remarkable happened at NASA. Twin brothers Mark and Scott Kelly were accepted into NASA; Mark as a shuttle pilot, and Scott into technical operations on the ground, at least initially. Eventually, both brothers became astronauts. They are the only siblings to have both been in space.
Whether it was intentional or not, having twin brothers gave NASA an important opportunity. They could use one twin as a control group, and send the other on a prolonged mission into space. That allowed NASA to carry out important research on the effects of space travel on the human body.
In March 2016, Scott Kelly returned from a year long (340 days) mission aboard the International Space Station, while his brother Mark stayed on Earth. Genetic samples were taken from each brother before and after Scott’s time aboard the ISS. Now, NASA has released the preliminary results of this unprecedented opportunity.
Expedition 46 Commander Scott Kelly of NASA is seen after returning to Ellington Field, Thursday, March 3, 2016 in Houston, Texas after his return to Earth the previous day. Kelly and Flight Engineers Mikhail Kornienko and Sergey Volkov of Roscosmos landed in their Soyuz TMA-18M capsule in Kazakhstan on March 1 (Eastern time).
NASA’s Human Research Program did the study, and the results were released at their Investigator’s Workshop on the week of January 23rd. The theme of that workshop was A New Dawn: Enabling Human Space Exploration. Though the studies are on-going, these initial results are interesting.
Omics
Mike Snyder, who is the Integrated Omics investigator, reported his findings. He found an altered level of lipids in Scott, the flight twin, which indicates inflammation. He also found increased 3-indolepropionic (IPA) in Mark, the ground twin. IPA is a potential brain antioxidant therapeutic, and also helps maintain normal insulin levels, to stabilize blood sugar after meals.
Telomeres and Telomerase
Telomeres and Telomerase are part of the chromosomal system in the human body. Susan Bailey reported that for Scott, the flight twin, the length of his white blood cell’s telomeres increased while in space. Typically, they decrease as a person ages. Once on Earth, they began to shorten again.
Telomerase, an enzyme that repairs telomeres, increased in both brothers in November, which could be related to a stressful family event at that time.
The Soyuz TMA-18M spacecraft is seen as it lands with Expedition 46 Commander Scott Kelly of NASA and Russian cosmonauts Mikhail Kornienko and Sergey Volkov in Kazakhstan on Wednesday, March 2, 2016. Photo Credit: (NASA/Bill Ingalls)
Cognitive Performance in Spaceflight
Mathias Basner is studying Cognitive Performance in Spaceflight, especially the difference in cognition between a 12-month mission and a six-month mission. Though he found a slight decrease in speed and accuracy after the mission, he found no real difference in cognition between 6 month and 12 month missions.
Biochemistry
Scott Smith’s investigation into biochemistry showed a decrease in bone density during the second half of Scott’s mission. Scott also had increased levels of a biochemical marker for inflammation once he returned to Earth.
Microbiome in the Gastro-Intestinal Tract
Fred Turek reported preliminary results of his investigation into the bacteria in the GI (microbiome) tract that help digestion. There were many differences in the twins’ biomes, but that was expected because of their different diets and environments. There were interesting differences in Scott’s biome between his time in space and his time on the ground. The ratio between two dominant bacterial groups shifted during his flight time compared to his ground time.
Immunome Studies
Emmanuel Mignot investigated changes in the bodies of both twins before and after a flu vaccine was given. Both twins showed increased levels of T-cell receptors after the vaccine, which was the expected immune response.
Genome Sequencing
Chris Mason is performing Genome Sequencing on the DNA and RNA contained within the twins’ white blood cells with his investigation. RNA sequencing showed that over 200,000 RNA molecules were expressed differently between the twins. Mason will look closer to see if a “space gene” could have been activated while Scott was in space.
Epigenomics
Andy Feinberg studies how the environment regulates our gene expression, which is known as epigenomics. Scott’s white blood cell DNA showed decreased levels of chemical modification while in flight, and a return to normal once back on Earth. The same level in Mark (the ground twin) increased midway through the study, but then returned to normal. There was variability between the twins, called epigenetic noise. This noise was higher in Scott during his spaceflight, and returned to baseline levels once back on Earth. This could indicate that some genes are more sensitive to the changing environment of spaceflight than others.
There’s a lot more research required to truly understand these results. Once they’re looked at in coordination with other physiological, psychological, and technological investigations, the picture will become clearer. Later in 2017, there will be a joint publication of further results, as well as individual research papers.
NASA’s goal is to make space travel safer for astronauts, and to make missions more effective and efficient. With all the talk of missions to Mars in the next decade, these results are arriving at the perfect time.
Image taken by the Viking 1 orbiter in June 1976, showing Mars thin atmosphere and dusty, red surface. Credits: NASA/Viking 1
Welcome back to our planetary weather series! Today, we take a look at Earth’s neighbor and possible “backup location” for humanity someday – Mars!
Mars is often referred to as “Earth’s Twin”, due to the similarities it has with our planet. They are both terrestrial planets, both have polar ice caps, and (at one time) both had viable atmospheres and liquid water on their surfaces. But beyond that, the two are quite different. And when it comes to their atmospheres and climates, Mars stands apart from Earth in some rather profound ways.
For instance, when it comes to the weather on Mars, the forecast is usually quite dramatic. Not only does Martian weather vary from day to day, it sometimes varies from hour to hour. That seems a bit unusual for a planet that has an atmosphere that is only 1% as dense as the Earth’s. And yet, Mars manages to really up the ante when it comes to extreme weather and meteorological phenomena.
Mars’ Atmosphere:
Mars has a very thin atmosphere which is composed of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen, along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates that measure 1.5 micrometers in diameter, which is what gives the Martian sky its tawny color when seen from the surface. Mars’ atmospheric pressure ranges from 0.4 to 0.87 kPa, which is the equivalent of about 1% of Earth’s at sea level.
This image illustrates possible ways methane might get into Mars’ atmosphere and also be removed from it. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan
Because of this thin atmosphere, and its greater distance from the Sun, the surface temperature of Mars is much colder than what we experience here on Earth. The planet’s average temperature is -63 °C (-82 °F), with a low of -143 °C (-226 °F) during the winter at the poles, and a high of 35 °C (95 °F) during summer and midday at the equator.
Due to the extreme lows in temperature at the poles, 25-30% of the carbon dioxide in the atmosphere freezes and becomes dry ice that is deposited on the surface. While the polar ice caps are predominantly water, the Martian North Pole has a layer of dry ice measuring one meter thick in winter, while the South Pole is covered by a permanent layer that is eight meters deep.
Trace amounts of methane and ammonia have also been detected in the Martian atmosphere. In the case of the former, it has an estimated concentration of about 30 parts per billion (ppb), though the Curiosity rover detected a “tenfold spike” on December 16th, 2014. This detection was likely localized, and the source remains a mystery. Similarly, the source of ammonia is unclear, though volcanic activity has been suggested as a possibility.
Meteorological Phenomena:
Mars is also famous for its intense dust storms, which can range from small tornadoes to planet-wide phenomena. Instances of the latter coincide with dust being blown into the atmosphere, causing it to be heated up from the Sun. The warmer dust-filled air rises and the winds get stronger, creating storms that can measure up to thousands of kilometers in width and last for months at a time. When they get this large, they can actually block most of the surface from view.
Image capturing an active dust storm on Mars. Image credits: NASA/JPL-Caltech/MSSS
Due to its thin atmosphere, low temperatures and lack of a magnetosphere, liquid precipitation (i.e. rain) does not take place on Mars. Basically, solar radiation would cause any liquid water in the atmosphere to disassociate into hydrogen and oxygen. And because of the cold and thin atmosphere, there is simply not enough liquid water on the surface to maintain a water cycle.
Occasionally, however, thin clouds do form in the atmosphere and precipitation falls in the form of snow. This consists primarily of carbon dioxide snow, which has been observed in the polar regions. However, small traces of frozen clouds carrying water have also been observed in Mars’ upper atmosphere in the past, producing snow that is restricted to high altitudes.
One such instance was observed on September 29th, 2008, when the Phoenix lander took pictures of snow falling from clouds that were 4 km (2.5 mi) above its landing site near the Heimdal Crater. However, data collected from the lander indicated that the precipitation vaporized before it could reach the ground.
Aurorae on Mars:
Auroras have also been detected on Mars, which are also the result of interaction between magnetic fields and solar radiation. While Mars has little magnetosphere to speak of, scientists determined that aurorae observed in the past corresponded to an area where the strongest magnetic field is localized on the planet. This was concluded by analyzing a map of crustal magnetic anomalies compiled with data from Mars Global Surveyor.
Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA
A notable example is the one that took place on August 14th, 2004, and which was spotted by the SPICAM instrument aboard the Mars Express. This aurora was located in the skies above Terra Cimmeria – at geographic coordinates 177° East, 52° South – and was estimated to be quite sizable, measuring 30 km across and 8 km high (18.5 miles across and 5 miles high).
More recently, an aurora was observed on Mars by the MAVEN mission, which captured images of the event on March 17th, 2015, just a day after an aurora was observed here on Earth. Nicknamed Mars’ “Christmas lights”, they were observed across the planet’s mid-northern latitudes and (owing to the lack of oxygen and nitrogen in Mars’ atmosphere) were likely a faint glow compared to Earth’s more vibrant display.
To date, Mars’ atmosphere, climate and weather patterns have been studied by dozens of orbiters, landers, and rovers, consisting of missions by NASA, Roscomos, as well as the European Space Agency and Indian federal space program. These include the Mariner 4 probe, which conducted the first flyby of Mars – a two-day operation that took place between July 14th and 15th, 1965.
The crude data it obtained was expanded on by the later later Mariner 6 and 7 missions (which conducted flybys in 1969). This was followed by the Viking1 and 2 missions, which reached Mars in 1976 and became the first spacecraft to land on the planet and send back images of the surfaces.
In the future, several additional missions are scheduled to reach the Red Planet, which are expected to teach us even more about its atmosphere, climate and weather patterns. What we find will reveal much about the planet’s deep past, its present condition, and perhaps even help us to build a future there.
13 Years on Mars! On Christmas Day 2016, NASA’s Opportunity rover scans around vast Endeavour crater as she ascends steep rocky slopes on the way to reach a water carved gully along the eroded craters western rim. This navcam camera photo mosaic was assembled from raw images taken on Sol 4593 (25 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
13 Years on Mars!
On Christmas Day 2016, NASA’s Opportunity rover scans around vast Endeavour crater as she ascends steep rocky slopes on the way to reach a water carved gully along the eroded craters western rim. This navcam camera photo mosaic was assembled from raw images taken on Sol 4593 (25 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s truly outstanding Opportunity rover continues “making new discoveries about ancient Mars” as she commemorates 13 Years since bouncing to a touchdown on Mars, in a feat that is “truly amazing” – the deputy chief scientist Ray Arvidson told Universe Today exclusively.
“Reaching the 13th year anniversary with a functioning rover making new discoveries about ancient Mars on a continuing basis is truly amazing,” Ray Arvidson, Opportunity Deputy Principal Investigator of Washington University in St. Louis, told Universe Today.
Put another way Opportunity is 13 YEARS into her 3 MONTH mission! And still going strong!
During the past year the world famous rover discovered “more extensive aqueous alteration within fractures and more mild alteration within the bedrock outcrops” at Endeavour crater, Arvidson elaborated.
And now she is headed to her next target – an ancient water carved gully!
The gully is situated about 0. 6 mile (1.6 km) south of the robots current location.
But to get there she first has to heroically ascend steep rocky slopes inclined over 20 degrees along the eroded craters western rim – and it’s no easy task! Slipping and sliding along the way and all alone on difficult alien terrain.
Furthermore she is 51 times beyond her “warrantied” life expectancy of merely 90 Sols promised at the time of landing so long ago – roving the surface of the 4th rock from the Sun during her latest extended mission; EM #10.
How was this incredible accomplishment achieved?
“Simply a well-made and thoroughly tested American vehicle,” Arvidson responded.
NASA’s Opportunity rover scans around and across to vast Endeavour crater on Dec. 19, 2016, as she climbs steep slopes on the way to reach a water carved gully along the eroded craters western rim. Note rover wheel tracks at center. This navcam camera photo mosaic was assembled from raw images taken on Sol 4587 (19 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
The six wheeled rover landed on Mars on January 24, 2004 PST on the alien Martian plains at Meridiani Planum -as the second half of a stupendous sister act.
Her twin sister Spirit, had successfully touched down 3 weeks earlier on January 3, 2004 inside 100-mile-wide Gusev crater and survived more than six years.
NASA’s Opportunity explores Spirit Mound after descending down Marathon Valley and looks out across the floor of vast Endeavour crater. This navcam camera photo mosaic was assembled from raw images taken on Sol 4505 (25 Sept 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
Opportunity concluded 2016 and starts 2017 marching relentlessly towards an ancient water carved gully along the eroded rim of vast Endeavour crater – the next science target on her heroic journey traversing across never before seen Red Planet terrains.
Huge Endeavour crater spans some 22 kilometers (14 miles) in diameter.
Throughout 2016 Opportunity was investigating the ancient, weathered slopes around the Marathon Valley location in Endeavour crater. The area became a top priority science destination after the slopes were found to hold a motherlode of ‘smectite’ clay minerals based on data from the CRISM spectrometer circling overhead aboard a NASA Mars orbiter.
The smectites were discovered via extensive, specially targeted Mars orbital measurements gathered by the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) spectrometer on NASA’s Mars Reconnaissance Orbiter (MRO) – accomplished earlier at the direction of Arvidson.
Opportunity was descending down Marathon Valley the past year to investigate the clay minerals formed in water. They are key to helping determine the habitability of the Red Planet when it was warmer and wetter billions of years ago.
What did Opportunity accomplish scientifically at Marathon Valley during 2016?
“Key here is the more extensive aqueous alteration within fractures and more mild alteration within the bedrock outcrops,” Arvidson explained to me.
“Fractures have red pebbles enhanced in Al and Si (likely by leaching out more soluble elements), hematite, and in the case of our scuffed fracture, enhanced sulfate content with likely Mg sulfates and other phases. Also the bedrock is enriched in Mg and S relative to other Shoemaker rocks and these rocks are the smectite carrier as observed from CRISM ATO data.”
Marathon Valley measures about 300 yards or meters long. It cuts downhill through the west rim of Endeavour crater from west to east – the same direction in which Opportunity drove downhill from a mountain summit area atop the crater rim.
Opportunity has been exploring Endeavour since arriving at the humongous crater in 2011. Endeavour crater was formed when it was carved out of the Red Planet by a huge meteor impact billions of years ago.
“Endeavour crater dates from the earliest Martian geologic history, a time when water was abundant and erosion was relatively rapid and somewhat Earth-like,” explains Larry Crumpler, a science team member from the New Mexico Museum of Natural History & Science.
Opportunity has been climbing up very steep and challenging slopes to reach the top of the crater rim. Then she will drive south to Cape Byron and the gully system.
“We have had some mobility issues climbing steep, rocky slopes. Lots of slipping and skidding, but evaluating the performance of the rover on steep, rocky and soil-covered slopes was one of the approved extended mission objectives,” Arvidson explained.
“We are heading out of Cape Tribulation, driving uphill to the southwest to reach the Meridiani plains and then to drive to the western side of Cape Byron to the head of a gully system.”
What’s ahead for 2017? What’s the importance of exploring the gully?
“Finish up work on Cape Tribulation, traverse to the head of the gully system and head downhill into one or more of the gullies to characterize the morphology and search for evidence of deposits,” Arvidson elaborated.
“Hopefully test among dry mass movements, debris flow, and fluvial processes for gully formation. The importance is that this will be the first time we will acquire ground truth on a gully system that just might be formed by fluvial processes. Will search for cross bedding, gravel beds, fining or coarsening upward sequences, etc., to test among hypotheses.”
How long will it take to reach the gully?
“Months to the gully,” replied Arvidson. After arriving at the top of the crater rim, the rover will actually drive part of the way on the Martian plains again during the southward trek to the gully.
“And we will be driving on the plains to drive relatively long distances with an intent of getting to the gully well before the winter season.”
As of today, Jan 31, 2017, long lived Opportunity has survived 4630 Sols (or Martian days) roving the harsh environment of the Red Planet.
Opportunity has taken over 216,700 images and traversed over 27.26 miles (43.87 kilometers) – more than a marathon.
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
See our updated route map below. It shows the context of the rovers over 13 year long traverse spanning more than the 26 mile distance of a Marathon runners race.
The rover surpassed the 27 mile mark milestone on November 6, 2016 (Sol 4546).
The power output from solar array energy production is currently 416 watt-hours, before heading into another southern hemisphere Martian winter in 2017. It will count as Opportunities 8th winter on Mars.
Meanwhile Opportunity’s younger sister rover Curiosity traverses and drills into the lower sedimentary layers at the base of Mount Sharp.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
13 Year Traverse Map for NASA’s Opportunity rover from 2004 to 2017. This map shows the entire 43 kilometer (27 mi) path the rover has driven on the Red Planet during more than 13 years and more than a marathon runners distance for over 4614 Sols, or Martian days, since landing inside Eagle Crater on Jan 24, 2004 – to current location at the western rim of Endeavour Crater. After descending down Marathon Valley and after studying Spirit Mound, the rover is now ascending back uphill on the way to a Martian water carved gully. Rover surpassed Marathon distance on Sol 3968 after reaching 11th Martian anniversary on Sol 3911. Opportunity discovered clay minerals at Esperance – indicative of a habitable zone – and searched for more at Marathon Valley. Credit: NASA/JPL/Cornell/ASU/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Image of the Mittens and Merrick Butte, in Monument Valley, Arizona. Credit: Wikipedia Commons/Wolfgang Staudt
During the 16h century, Spanish explorers ventured north from Mexico looking for gold and the legendary “Seven cities of Cibola”. What they found instead were some of the most amazing natural formations in the world, which are today known as “buttes”. To the local Hopi, Navajo, and other indigenous nations, these features – which resemble tall, isolated plateaus – have been regarded as sacred sites since time immemorial.
By the beginning of the 19th century, the term “butte” entered common parlance and quickly became adopted by the geological community. And while their existence was something of a mystery for thousands of years, spawning mythological connections and folk tales, improvements in the fields of Earth sciences and geology have led scientists to understand what these features are and how they are formed.
Definition:
By definition, a Butte is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top. The word “butte” comes from a French word meaning “small hill”. They are not to be confused with Mesas or Plateaus, which are typically differentiated based on the fact that their top surfaces are larger than their vertical faces, while a butte is taller than it is wide. However, definitions of the surface areas of mesas and buttes vary.
The Courthouse Butte, located near the town of Sedona, Arizona. Credit: Wikipedia Commons
One source states that a mesa has a surface area of less than 10 square kilometers, while a butte has a surface area less than 1,000 square meters. Another source states that the surface area of a mesa is larger than 2.59 square kilometers. However, all sides are in agreement that is the difference between their vertical and horizontal measurements that are key.
Formation:
Both buttes and mesas are formed by the same geological process, which involves the physical weathering of rock formations. Essentially, this involves the surface material of a hill or mountain (the cap rock) resists wind and water erosion, but the underlying materials do not. Over time, the underlying material is stripping away, leaving an isolated, standing feature with a flat top.
The top layer of a butte is a hardened layer of rock that is resistant to erosion. This top layer, called the cap rock, is usually composed of sedimentary rock, but sometimes is the remains of cooled and hardened lava that had spread out across the landscape in repeated flows from fissures or cracks in the ground.
Beneath this flat, protective cap of rock, horizontal layers of softer sedimentary rock are found. To varying degrees, these layers are not as resistant to wind and water erosion. As a result, when the softer rock is stripped away, a standing, isolated rock is left behind. Typically, buttes are found in arid and semiarid regions.
Merrick’s Butte, in Monument Valley, Utah. Credit: Wikipedia Commons/Ernst Brötz
Because water evaporates quickly in these normally dry environments, plants and other ground cover are scarce. Left exposed to the action of running water, the bare sides of the softer rock layers of buttes are eroded away over time. The base of these landforms is often gently sloped, contrasting with the almost-vertical sides leading down from the top. Rock material that has been eroded from the sides is carried downward, forming this sloping base.
Notable Buttes:
Because of their isolated and imposing nature, many buttes have become geographical land markers and major tourist destinations. They also figured prominently in the spiritual beliefs and creation myths of the indigenous peoples across North America. Buttes can be found all over North America, though they are most commonly found in the arid regions of the American Southwest.
For example, there is the Courthouse Butte, a prominent feature located just north of the Village of Oak Creek, and south of the town of Sedona in Yavapai County. Then there’s the Elephant Butte, which is located in the Elephant Butte Lake State Park in Sierra Country, New Mexico,. This geographical feature is so-named because of the combination of a vertical side and a sloping side, which resemble the shape of an elephant.
Bear Butte in South Dakota also has a long history of being a geological and cultural significant feature. Long before the arrival of European settlers, Bear Butte featured prominently in the religious and mythological traditions of the Lakota, Sioux and Cheyenne nations. To the Lakota and Sioux, the feature was known as “Matho Paha” (literally, Bear Mountain), while the Cheyenne referred to it as Nahkohe-vose (“bear hill”).
Bear Butte (aka. Bear Mountain or Bear Hill),, located in South Dakota. Credit: Jerrye & Roy Klotz, MD.
According to Cheyenne mythology, it was here that Ma’heo’o (God, or the Great Spirit) imparted the knowledge from which the Cheyenne base their religion, political, social and economic customs to the prophet Sweet Medicine. Today, the location remains a sacred site for many indigenous peoples, who make pilgrimages to leave prayer cloths and tobacco bundles tied to branches taken from the trees that surround the butte.
To the north, buttes can be found in the Canadian provinces of Saskatchewan, Alberta and British Columbia, in regions that are arid and semi-arid. For example, there is the Pilot Butte, which is located in southern Saskatchewan, near the town of the same name. This feature’s name is derived from the fact that the flat-topped butte served as a lookout for hunting buffalo and as a landmark for planes approaching the provincial capitol of Regina.
And there’s Lone Butte, a prehistoric basalt feature located in the southern Cariboo Plateau in central British Columbia. A part of the geological formation known as the Chilcotin Group, this feature was formed roughly six million years ago as a result of the extensive volcanic activity in the region.
Buttes on Other Planets:
Buttes have also been spotted on other planets in the Solar System, where they are also linked to geological activity and erosion. For example, NASA’s Curiosity rover mission has taken extensive images of the area currently known as the “Murray Buttes” region on Mars, which is located in the lower region of Mount Sharp (in the Gale Crater). In addition, Curiosity has taken drill samples from the surface rock in the region.
Wide-angle mosaic of a butte with sandstone layers showing cross-bedding, in the Murray Buttes region on lower Mount Sharp. Credit: NASA/JPL/MSSS/Ken Kremer/Marco Di Lorenzo
At one time, this crater was believed to be a standing body of water, which was largely responsible for the creation of these features. As Ashwin Vasavada, the Curiosity Project Scientist of NASA’s Jet Propulsion Laboratory, described the area as being “reminiscent of parts of the American southwest because of its butte and mesa landscape. In both areas, thick layers of sediment were deposited by wind and water, eventually resulting in a “layer cake” of bedrock that then began to erode away as conditions changed. In both places, more resistant sandstone layers cap the mesas and buttes because they protect the more easily eroded, fine-grained rock underneath. ”
Buttes have also been photographed by the Mars Reconnaissance Orbiter’s (MRO) HiRISE instrument. These include the many buttes spotted in the Candor Chasma region – part of the Valles Marineris canyon system – back in 2007. The Viking 1 orbiter also noted the presence of many buttes in the Cydonia region during its flyby in 1976 – the occasion when it took pictures of the “Face of Mars” (later revealed to be a mesa).
Much like polygonal ridges that have been observed in the Medusae Fossae region and other locations across Mars (and Earth), these features are believed to be the remains of volcanic rock that remained in place after the surrounding rock was stripped away by erosion.
Ongoing studies into the various forces that shape our planet has allowed us to understand just how dynamic and changing it is. In addition, developments in space exploration and the planetary sciences have helped us to realize that Earth has a lot in common with other planets in our Solar System.
The vortex coronagraph at the Keck Observatory captured this image of the protoplanetary disk surrounding the young star HD 141569, which is about 380 light years from Earth. Image: NASA/JPL-Caltech
The study of exoplanets has advanced a great deal in recent years, thanks in large part to the Kepler mission. But that mission has its limitations. It’s difficult for Kepler, and for other technologies, to image regions close to their stars. Now a new instrument called a vortex coronagraph, installed at Hawaii’s Keck Observatory, allows astronomers to look at protoplanetary disks that are in very close proximity to the stars they orbit.
The problem with viewing disks of dust, and even planets, close to their stars is that stars are so much brighter than objects that orbit them. Stars can be billions of times brighter than the planets near them, making it almost impossible to see them in the glare. “The power of the vortex lies in its ability to image planets very close to their star, something that we can’t do for Earth-like planets yet,” said Gene Serabyn of NASA’s Jet Propulsion Laboratory (JPL). “The vortex coronagraph may be key to taking the first images of a pale blue dot like our own.”
“The power of the vortex lies in its ability to image planets very close to their star, something that we can’t do for Earth-like planets yet.” – Gene Serabyn, JPL.
“The vortex coronagraph allows us to peer into the regions around stars where giant planets like Jupiter and Saturn supposedly form,” said Dmitri Mawet, research scientist at NASA’s Jet Propulsion Laboratory and Caltech, both in Pasadena. “Before now, we were only able to image gas giants that are born much farther out. With the vortex, we will be able to see planets orbiting as close to their stars as Jupiter is to our sun, or about two to three times closer than what was possible before.”
Rather than masking the light of stars, like other methods of viewing exoplanets, the vortex coronagraph redirects light away from the detectors by combining light waves and cancelling them out. Because there is no occulting mask, the vortex coronagraph can capture images of regions much closer to stars than other coronagraphs can. Dmitri Mawet, research scientist who invented the new coronagraph, compares it to the eye of a storm.
The vortex mask shown at left is made out of synthetic diamond. When viewed with a scanning electron microscope, right, the “vortex” microstructure of the mask is revealed. Image credit: University of Liège/Uppsala University
“The instrument is called a vortex coronagraph because the starlight is centered on an optical singularity, which creates a dark hole at the location of the image of the star,” said Mawet. “Hurricanes have a singularity at their centers where the wind speeds drop to zero — the eye of the storm. Our vortex coronagraph is basically the eye of an optical storm where we send the starlight.”
The results from the vortex coronagraph are presented in two papers (here and here) published in the January 2017 Astronomical Journal. One of the studies was led by Gene Serabyn of JPL, who is also head of the Keck vortex project. That study presented the first direct image of HIP79124 B, a brown dwarf that is 23 AU from its star, in the star-forming region called Scorpius-Centaurus.
The vortex coronagraph captured this image of the brown dwarf PIA21417. Image: NASA/JPL-Caltech
“The ability to see very close to stars also allows us to search for planets around more distant stars, where the planets and stars would appear closer together. Having the ability to survey distant stars for planets is important for catching planets still forming,” said Serabyn.
“Having the ability to survey distant stars for planets is important for catching planets still forming.” – Gene Serabyn, JPL.
The second of the two vortex studies presented images of a protoplanetary disk around the young star HD141569A. That star actually has three disks around it, and the coronagraph was able to capture an image of the innermost ring. Combining the vortex data with data from the Spitzer, WISE, and Herschel missions showed that the planet-forming material in the disk is made up pebble-size grains of olivine. Olivine is one of the most abundant silicates in Earth’s mantle.
“The three rings around this young star are nested like Russian dolls and undergoing dramatic changes reminiscent of planetary formation,” said Mawet. “We have shown that silicate grains have agglomerated into pebbles, which are the building blocks of planet embryos.”
These images and studies are just the beginning for the vortex coronagraph. It will be used to look at many more young planetary systems. In particular, it will look at planets near so-called ‘frost lines’ in other solar systems. The is the region around star systems where it’s cold enough for molecules like water, methane, and carbon dioxide to condense into solid, icy grains. Current thinking says that the frost line is the dividing line between where rocky planets and gas planets are formed. Astronomers hope that the coronagraph can answer questions about hot Jupiters and hot Neptunes.
Hot Jupiters and Neptunes are large gaseous planets that are found very close to their stars. Astronomers want to know if these planets formed close to the frost line then migrated inward towards their stars, because it’s impossible for them to form so close to their stars. The question is, what forces caused them to migrate inward? “With a bit of luck, we might catch planets in the process of migrating through the planet-forming disk, by looking at these very young objects,” Mawet said.
SpaceX is repurposing historic pad 39A at the Kennedy Space Center, Florida for launches of the Falcon 9 rocket. Ongoing pad preparation by work crews is seen in this current view taken on Jan. 27, 2017. Credit: Ken Kremer/kenkremer.com
SpaceX is repurposing historic pad 39A at the Kennedy Space Center, Florida for launches of the Falcon 9 rocket. Ongoing pad preparation by work crews is seen in this current view taken on Jan. 27, 2017. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – SpaceX announced Sunday (Jan. 29) a significant shuffle to the Falcon 9 launch schedule, saying that a key NASA mission to resupply the space station is moving to the head of the line and will now be their first mission to launch from historic pad 39A at the Kennedy Space Center – formerly used to launch space shuttles.
The late breaking payload switch will allow SpaceX, founded by billionaire CEO Elon Musk, additional time to complete all the extensive ground support work and pad testing required for repurposing seaside Launch Complex 39A from launching the NASA Space Shuttle to the SpaceX Falcon 9.
Blastoff of the 22-story tall SpaceX Falcon 9 carrying an unmanned Dragon cargo freighter with NASA as customer on the CRS-10 resupply mission to the International Space Station (ISS) could come as soon as mid-February, said SpaceX.
“SpaceX announced today that its first launch from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida will be the CRS-10 mission to the International Space Station,” said SpaceX in a statement.
CRS-10 counts as SpaceX’s tenth cargo flight to the ISS since 2012 under contract to NASA.
SpaceX is renovating Launch Complex 39A at the Kennedy Space Center for launches of commercial and human rated Falcon 9 rockets as well as the Falcon Heavy, as seen here during Dec 2016 with construction of a dedicated new transporter/erector. Credit: Ken Kremer/kenkremer.com
Crews have been working long hours to modify pad 39A and get it ready for Falcon 9 launches. Also, the newly built transporter erector launcher was seen raised at the pad multiple times in recent days. The transporter will move the rocket horizontally up the incline at the pad, and then erect it vertically.
“This schedule change allows time for additional testing of ground systems ahead of the CRS-10 mission,” SpaceX announced in a statement.
The surprise switch in customers means that the previously planned first Falcon 9 launch from pad 39A of the commercial EchoStar 23 communications satellite is being pushed off to a later date – perhaps late February.
Until now, EchoStar 23 was slated to be the first satellite launched by a Falcon 9 from Launch Complex 39A on NASA’s Kennedy Space Center. It could have come as soon as by the end of this week.
However, the Falcon 9 launch date from pad 39A has slipped repeatedly in January, with this week on Feb. 3 as the most recently targeted ‘No Earlier Than’ NET date.
SpaceX successfully resumed launches of the Falcon 9 earlier this month when the first flock of 10 Iridium NEXT mobile voice and data relay satellites blasted off on the Iridium 1 mission from Vandenberg Air Force Base in California on Jan. 14, 2017.
NASA now gets the first dibs for using pad 39A which has lain dormant for nearly six years since Space Shuttle Atlantis launched on the final shuttle mission STS 135 in July 2011.
The last Dragon resupply mission to the ISS blasted off on July 18, 2016 on the CRS-9 mission. The Falcon 9 first stage was also successfully recovered via a propulsive soft landing back at the Cape at night.
SpaceX Falcon 9 launches and lands over Port Canaveral in this streak shot showing rockets midnight liftoff from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida at 12:45 a.m. EDT on July 18, 2016 carrying Dragon CRS-9 craft to the International Space Station (ISS) with almost 5,000 pounds of cargo and docking port. View from atop Exploration Tower in Port Canaveral. Credit: Ken Kremer/kenkremer.com
The last successful Falcon 9 launch from Space Launch Complex-40 took place on Aug. 14, 2016, carrying the JCSAT-16 Japanese communications satellite to orbit.
Launch of SpaceX Falcon 9 carrying JCSAT-16 Japanese communications satellite to orbit on Aug. 14, 2016 at 1:26 a.m. EDT from Space Launch Complex 40 at Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com
But following the unexpected launch pad explosion on Sept 1, 2016 that completely destroyed a Falcon 9 and the $200 million Amos-6 commercial payload during a prelaunch fueling test, pad 40 suffered extensive damage.
Furthermore it is not known when the pad will be ready to resume launches.
Aerial view of pad and strongback damage at SpaceX Launch Complex-40 as seen from the VAB roof on Sept. 8, 2016 after fueling test explosion destroyed the Falcon 9 rocket and AMOS-6 payload at Cape Canaveral Air Force Station, FL on Sept. 1, 2016. Credit: Ken Kremer/kenkremer.com
So SpaceX has had to switch launch pads for near term future flights and press pad 39A into service much more urgently, and the refurbishing and repurposing work is not yet complete.
To date SpaceX has not rolled a Falcon 9 rocket to pad 39A, not raised it to launch position, not conducted a fueling exercise and not conducted a static fire test. All the fit checks with a real rocket remain to be run.
Thus the current launch target of mid-February for CRS-10 remains a target date and not a firm launch date. EchoStar 23 is next in line.
“The launch is currently targeted for no earlier than mid-February,” SpaceX elaborated.
“Following the launch of CRS-10, first commercial mission from 39A is currently slated to be EchoStar XXIII.”
Once the pad is ready, SpaceX plans an aggressive launch schedule in 2017.
“The launch vehicles, Dragon, and the EchoStar satellite are all healthy and prepared for launch,” SpaceX stated.
The history making first use of a recycled Falcon 9 carrying the SES-10 communications satellite could follow as soon as March, if all goes well.
Incredible sight of pleasure craft zooming past SpaceX Falcon 9 booster from Thaicom-8 launch on May 27, 2016 as it arrives at the mouth of Port Canaveral, FL, atop droneship platform on June 2, 2016. Credit: Ken Kremer/kenkremer.com
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
SpaceX crews are renovating Launch Complex 39A at the Kennedy Space Center for launches of commercial and human rated Falcon 9 rockets as well as the Falcon Heavy, as seen here during Dec 2016 with construction of a dedicated new transporter/erector. At new rocket processing hangar sits at left. Credit: Ken Kremer/kenkremer.com
Planets and other objects in our Solar System. Credit: NASA.
Humanity’s understanding of what constitutes a planet has changed over time. Whereas our most notable magi and scholars once believed that the world was a flat disc (or ziggurat, or cube), they gradually learned that it was in fact spherical. And by the modern era, they came to understand that the Earth was merely one of several planets in the known Universe.
And yet, our notions of what constitutes a planet are still evolving. To put it simply, our definition of planet has historically been dependent upon our frame of reference. In addition to discovering extra-solar planets that have pushed the boundaries of what we consider to be normal, astronomers have also discovered new bodies in our own backyard that have forced us to come up with new classification schemes.
History of the Term:
To ancient philosophers and scholars, the Solar Planets represented something entirely different than what they do today. Without the aid of telescopes, the planets looked like particularly bright stars that moved relative to the background stars. The earliest records on the motions of the known planets date back to the 2nd-millennium BCE, where Babylonian astronomers laid the groundwork for western astronomy and astrology.
These include the Venus tablet of Ammisaduqa, which catalogued the motions of Venus. Meanwhile, the 7th-century BCE MUL.APIN tablets laid out the motions of the Sun, the Moon, and the then-known planets over the course of the year (Mercury, Venus, Mars, Jupiter and Saturn). The Enuma anu enlil tablets, also dated to the 7th-century BCE, were a collection of all the omens assigned to celestial phenomena and the motions of the planets.
By classical antiquity, astronomers adopted a new concept of planets as bodies that orbited the Earth. Whereas some advocated a heliocentric system – such as 3rd-century BCE astronomer Aristarchus of Samos and 1st-century BCE astronomer Seleucus of Seleucia – the geocentric view of the Universe remained the most widely-accepted one. Astronomers also began creating mathematical models to predict their movements during this time.
This culminated in the 2nd century CE with Ptolemy’s (Claudius Ptolemaeus) publication of the Almagest, which became the astronomical and astrological canon in Europe and the Middle East for over a thousand years. Within this system, the known planets and bodies (even the Sun) all revolved around the Earth. In the centuries that followed, Indian and Islamic astronomers would added to this system based on their observations of the heavens.
By the time of the Scientific Revolution (ca. 15th – 18th centuries), the definition of planet began to change again. Thanks to Nicolaus Copernicus, Galileo Galilei, and Johannes Kepler, who proposed and advanced the heliocentric model of the Solar System, planets became defined as objects that orbited the Sun and not Earth. The invention of the telescope also led to an improved understanding of the planets, and their similarities with Earth.
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
Between the 18th and 20th centuries, countless new objects, moons and planets were discovered. This included Ceres, Vesta, Pallas (and the Main Asteroid Belt), the planets Uranus and Neptune, and the moons of Mars and the gas giants. And then in 1930, Pluto was discovered by Clyde Tombaugh, which was designated as the 9th planet of the Solar System.
Throughout this period, no formal definition of planet existed. But an accepted convention existed where a planet was used to described any “large” body that orbited the Sun. This, and the convention of a nine-planet Solar System, would remain in place until the 21st century. By this time, numerous discoveries within the Solar System and beyond would lead to demands that a formal definition be adopted.
Working Group on Extrasolar Planets:
While astronomers have long held that other star systems would have their own system of planets, the first reported discovery of a planet outside the Solar System (aka. extrasolar planet or exoplanet) did not take place until 1992. At this time, two radio astronomers working out of the Arecibo Observatory (Aleksander Wolszczan and Dale Frail) announced the discovery of two planets orbiting the pulsar PSR 1257+12.
The first confirmed discovery took place in 1995, when astronomers from the University of Geneva (Michel Mayor and Didier Queloz) announced the detection of 51 Pegasi. Between the mid-90s and the deployment of the Kepler space telescope in 2009, the majority of extrasolar planets were gas giants that were either comparable in size and mass to Jupiter or significantly larger (i.e. “Super-Jupiters”).
Earlier today, NASA announced that Kepler had confirmed the existence of 1,284 new exoplanets, the most announced at any given time. Credit: NASA
These new discoveries led the International Astronomical Union (IAU) to create the Working Group of Extrasolar Planets (WGESP) in 1999. The stated purpose of the WGESP was to “act as a focal point for international research on extrasolar planets.” As a result of this ongoing research, and the detection of numerous extra-solar bodies, attempts were made to clarify the nomenclature.
As of February 2003, the WGESP indicated that it had modified its position and adopted the following “working definition” of a planet:
1) Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars or stellar remnants are “planets” (no matter how they formed). The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our Solar System.
2) Substellar objects with true masses above the limiting mass for thermonuclear fusion of deuterium are “brown dwarfs”, no matter how they formed nor where they are located.
3) Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not “planets”, but are “sub-brown dwarfs” (or whatever name is most appropriate).
As of January 22nd, 2017, more than 2000 exoplanet discoveries have been confirmed, with 3,565 exoplanet candidates being detected in 2,675 planetary systems (including 602 multiple planetary systems).
The number of confirmed exoplanet discoveries, by year. Credit: NASA
2006 IAU Resolution:
During the early-to-mid 2000s, numerous discoveries were made in the Kuiper Belt that also stimulated the planet debate. This began with the discovery of Sedna in 2003 by a team of astronomers (Michael Brown, Chad Trujillo and David Rabinowitz) working at the Palomar Observatory in San Diego. Ongoing observations confirmed that it was approx 1000 km in diameter, and large enough to undergo hydrostatic equilibrium.
This was followed by the discovery of Eris – an even larger object (over 2000 km in diameter) – in 2005, again by a team consisting of Brown, Trujillo, and Rabinowitz. This was followed by the discovery of Makemake on the same day, and Haumea a few days later. Other discoveries made during this period include Quaoar in 2002, Orcus in 2004, and 2007 OR10 in 2007.
The discovery of a several objects beyond Pluto’s orbit that were large enough to be spherical led to efforts on behalf of the IAU to adopt a formal definition of a planet. By October 2005, a group of 19 IAU members narrowed their choices to a shortlist of three characteristics. These included:
A planet is any object in orbit around the Sun with a diameter greater than 2000 km. (eleven votes in favour)
A planet is any object in orbit around the Sun whose shape is stable due to its own gravity. (eight votes in favour)
A planet is any object in orbit around the Sun that is dominant in its immediate neighbourhood. (six votes in favour)
After failing to reach a consensus, the committee decided to put these three definitions to a wider vote. This took place in August of 2006 at the 26th IAU General Assembly Meeting in Prague. On August 24th, the issue was put to a final draft vote, which resulted in the adoption of a new classification scheme designed to distinguish between planets and smaller bodies. These included:
(1) A “planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.
(2) A “dwarf planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.
(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as “Small Solar-System Bodies”.
In accordance with this resolution, the IAU designated Pluto, Eris, and Ceres into the category of “dwarf planet”, while other Trans-Neptunian Objects (TNOs) were left undeclared at the time. This new classification scheme spawned a great deal of controversy and some outcries from the astronomical community, many of whom challenged the criteria as being vague and debatable in their applicability.
The presently-known largest trans-Neptunian objects (TNO), the discovery of which prompted the current IAU definition of planet. Credit: Larry McNish, Data: M.Brown)
For instance, many have challenged the idea of a planet clearing its neighborhood, citing the existence of near-Earth Objects (NEOs), Jupiter’s Trojan Asteroids, and other instances where large planets share their orbit with other objects. However, these have been countered by the argument that these large bodies do not share their orbits with smaller objects, but dominate them and carry them along in their orbits.
Another sticking point was the issue of hydrostatic equilibrium, which is the point where a planet has sufficient mass that it will collapse under the force of its own gravity and become spherical. The point at which this takes place remains entirely unclear thought, and some astronomers therefore challenge it being included as a criterion.
In addition, some astronomers claim that these newly-adopted criteria are only useful insofar as Solar planets are concerned. But as exoplanet research has shown, planets in other star star systems can be significantly different. In particular, the discovery of numerous “Super Jupiters” and “Super Earths” has confounded conventional notions of what is considered normal for a planetary system.
In June 2008, the IAU executive committee announced the establishment of a subclass of dwarf planets in the hopes of clarifying the definitions further. Comprising the recently-discovered TNOs, they established the term “plutoids”, which would thenceforth include Pluto, Eris and any other future trans-Neptunian dwarf planets (but excluded Ceres). In time, Haumea, Makemake, and other TNOs were added to the list.
Despite these efforts and changes in nomenclature, for many, the issue remains far from resolved. What’s more, the possible existence of Planet 9 in the outer Solar System has added more weight to the discussion. And as our research into exoplanets continues – and uncrewed (and even crewed) mission are made to other star systems – we can expect the debate to enter into a whole new phase!
This image shows a region in Saturn's outer B ring. NASA's Cassini spacecraft viewed this area at a level of detail twice as high as it had ever been observed before. And from this view, it is clear that there are still finer details to uncover. Credit: NASA/JPL-Caltech/Space Science Institute
As the Cassini spacecraft moves ever closer to Saturn, new images provide some of the most-detailed views yet of the planet’s spectacular rings. From its “Ring-Grazing” orbit phase, Cassini’s cameras are resolving details in the rings as small as 0.3 miles (550 meters), which is on the scale of Earth’s tallest buildings.
On Twitter, Cassini Imaging Team Lead Carolyn Porco called the images “outrageous, eye-popping” and the “finest Cassini images of Saturn’s rings.”
Project Scientist Linda Spilker said the ridges and furrows in the rings remind her of the grooves in a phonograph record.
These images are giving scientists the chance to see more details about ring features they saw earlier in the mission, such as waves, wakes, and things they call ‘propellers’ and ‘straw.’
This Cassini image features a density wave in Saturn’s A ring (at left) that lies around 134,500 km from Saturn. Density waves are accumulations of particles at certain distances from the planet. This feature is filled with clumpy perturbations, which researchers informally refer to as “straw.” Credit: NASA/JPL-Caltech/Space Science Institute
As of this writing, Cassini just started the 10th orbit of the 20-orbit ring-grazing phase, which has the spacecraft diving past the outer edge of the main ring system. The ring-grazing orbits began last November, and will continue until late April, when Cassini begins its grand finale. During the 22 finale orbits, Cassini will repeatedly plunge through the gap between the rings and Saturn. The first of these plunges is scheduled for April 26.
The spacecraft is actually close enough to the ‘F’ ring that occasionally tenuous particle strike Cassini, said project scientist Linda Spilker, during a Facebook Live event today.
“These are very small and tenuous, only a few microns in size,” Spilker said, “like dust particles you’d see in the sunlight. We can actually ‘hear’ them hitting the spacecraft in our data, but these particles are so small, they won’t hurt Cassini.”
Spilker has envisioned holding a ring particle in her hand. What would it look like?
“We have evidence of the particles that have an icy core covered with fluffy regolith material that is very porous,” she said, “and that means the particle can heat up and cool down very quickly compared to a solid ice cube.”
The straw features are caused by clumping ring particles and the propellers are caused by small, embedded moonlets that creates propeller shaped wakes in the rings.
The wavemaker moon, Daphnis, is featured in this view, taken as NASA’s Cassini spacecraft made one of its ring-grazing passes over the outer edges of Saturn’s rings on Jan. 16, 2017. This is the closest view of the small moon obtained yet. Daphnis is 5 miles or 8 kilometers across. Credit: NASA/JPL-Caltech/Space Science Institute
This stunning view of the moon Daphnis shows the moon interacting with the ring particles, creating waves in the rings around it.
A close-up of Saturn and its rings. Assembled using raw uncalibrated RGB filtered images taken by the Cassini spacecraft on January 18 2017. Credit: NASA/JPL-Caltech/SSI/image editing by Kevin M. Gill
“These close views represent the opening of an entirely new window onto Saturn’s rings, and over the next few months we look forward to even more exciting data as we train our cameras on other parts of the rings closer to the planet,” said Matthew Tiscareno, a Cassini scientist who studies Saturn’s rings at the SETI Institute, Mountain View, California. Tiscareno planned the new images for the camera team.
M33, the Triangulum Spiral Galaxy, seen here in a 4.3 hour exposure image. Astronomers used JWST to examine a section of its south spiral arm to search out and find nearly 800 newly forming stars. Credit and copyright: John Chumack.
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Triangulum Galaxy, also known as Messier 33. Enjoy!
During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these is the Triangulum Galaxy, a spiral galaxy located approximately 3 million light-years from Earth in the direction of the Triangulum constellation. As the third-largest member of the Local Group of galaxies (behind the Andromeda Galaxy and the Milky Way), it is the one of the most distant objects that can be seen with the naked eye. Much like M32, M33 is very close to Andromeda, and is believed to be a satellite of this major galaxy.
Description:
At some 3 million light years away from Earth, the Triangulum Galaxy is the third largest galaxy in our Local Group and it may be a gravitationally bound companion of the Andromeda Galaxy. Its beautiful spiral arms show multitudes of red HII regions and blue clouds of young stars. The largest of these HII regions (NGC 604) spans nearly 1500 across and is the largest so far known.
The Triangulum Galaxy (M33), taken by the Swift Gamma-Ray Burst Mission. Credit: NASA/Swift
It has a spectrum similar to the Orion Nebula – our own Milky Way’s most celebrated starbirth region. “M33 is a gigantic laboratory where you can watch dust being created in novae and supernovae, being distributed in the winds of giant stars, and being reborn in new stars,” said University of Minnesota researcher and lead author Elisha Polomski. By studying M33, “you can see the Universe in a nutshell.”
Of course, our curiousity about our neighboring galaxy has driven us to try to understand more over the years. Once Edwin Hubble set the standard with Cepheid variables, we began measuring distance by discovering about 25 of them in M33. By 2004 we were studying the red giant star branch to peer even further. As A.W. McConnachie said in a 2004 study of the galaxy:
“The absolute bolometric luminosity of the point of core helium ignition in old, metal-poor, red giant stars is of roughly constant magnitude, varying only very slightly with mass or metallicity. It can thus be used as a standard candle. This technique then allows for the determination of realistic uncertainties which reflect the quality of the luminosity function used. Finally, we apply our technique to the Local Group spiral galaxy M33 and the dwarf galaxies Andromeda I and II, and derive distance. The result for M33 is in excellent agreement with the Cepheid distances to this galaxy, and makes the possibility of a significant amount of reddening in this object unlikely.”
By 2005, astronomers had detected two water masers on either side of M33 and for the first time ever – revealed what direction it as going in. According to Andreas Brunthaler (et al), who published a study about the distance and proper motion of the galaxy in 2005:
“We measured the angular rotation and proper motion of the Triangulum Galaxy (M33) with the Very Long Baseline Array by observing two H2O masers on opposite sides of the galaxy. By comparing the angular rotation rate with the inclination and rotation speed, we obtained a distance of 730 +/- 168 kiloparsecs. This distance is consistent with the most recent Cepheid distance measurement. This distance is consistent with the most recent Cepheid distance measurement. M33 is moving with a velocity of 190 +/- 59 kilometers per second relative to the Milky Way. These measurements promise a method to determine dynamical models for the Local Group and the mass and dark-matter halos of M31, M33, and the Milky Way.”
Composite image of the Triangulum Galaxy (Messier 33), taken at Mount Lemmon Observatory. Credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona
Yes, it’s moving toward the Andromeda Galaxy, much like how Andromeda is moving towards us! In 2006, a group of astronomers announced the discovery of an eclipsing binary star in M33. As A.Z. Bonanos, the lead author of the study that detailed the discovery, said:
“We present the first direct distance determination to a detached eclipsing binary in M33, which was found by the DIRECT Project. Located in the OB 66 association, it was one of the most suitable detached eclipsing binaries found by DIRECT for distance determination, given its 4.8938 day period.”
By studying the eclipsing binary, astronomers soon knew their size, distance, temperature and absolute magnitude. But more was yet to come! In 2007, the Chandra X-ray Observatory revealed even more when a black hole nearly 16 times the mass of the Sun was revealed. The black hole, named M33 X-7, orbits a companion star which it eclipses every 3.5 days. This means the companion star must also have an incredibly large mass as well….
Yet how huge must the parent star have been to have formed a black hole in advance of its companion? As Jerome Orosz, of San Diego State University, was quoted as saying in a 2007 Chandra press release:
“This discovery raises all sorts of questions about how such a big black hole could have been formed. Massive stars can be much less extravagant than people think by hanging onto a lot more of their mass toward the end of their lives. This can have a big effect on the black holes that these stellar time-bombs make.”
Artist’s rendering of the black hole found in orbit of the large blue star in M33 . Credit: Chandra/Harvard/HST
Stellar bombs? You bet. Gigantic stellar explosions even. Although no supernovae events have been detected in the Triangulum galaxy, it certainly doesn’t lack for evidence of supernova remnants. According to a 2004 study by F. Haberl and W. Pietsch of the Max-Planck-Institute:
“We present a catalogue of 184 X-ray sources within 50′ of the nucleus of the local group spiral galaxy M 33. The catalogue is derived from an analysis of the complete set of ROSAT archival data pointed in the direction of M 33 and contains X-ray position, existence likelihood, count rates and PSPC spectral hardness ratios. To identify the sources the catalog was correlated with previous X-ray catalogues, optical and radio catalogues. In addition sources were classified according to their X-ray properties. We find seven candidates for supersoft X-ray sources, of which two may be associated with known planetary nebulae in M 33. The majority of X-ray detected supernova remnants is also detected at radio frequencies and seen in optical lines. The low overall X-ray detection rate of optically selected SNRs can probably be attributed to their expansion into interstellar matter of low density.”
Or the creation of black holes…
History of Observation:
While the Triangulum Galaxy was probably first observed by Hodierna before 1654 (back when skies were dark), it was independently rediscovered by Charles Messier, and cataloged by him on August 25, 1764. As he recorded in his notes on the occasion:
“I have discovered a nebula between the head of the northern Fish and the large Triangle, a bit distant from a star which had not been known, of sixth magnitude, of which I have determined the position; the right ascension of that star was 22d 7′ 13″, and its declination 29d 54′ 10″ north: near that star, there is another one which is the first of Triangulum, described by the letter b. Flamsteed described it in his catalog, of sixth magnitude; it is less beautiful than that of which I have given the position, and one should set it to the rank of the stars of the eighth class. The nebula is a whitish light of 15 minutes in diameter, of an almost even density, despite a bit more luminous at two third of its diameter; it doesn’t contain any star: one sees it with difficulty with an ordinary refractor of one foot.”
The location of the Triangulum Galaxy in the night sky. Credit: Wikisky
While Sir William Herschel wouldn’t publish papers on Messier’s findings, he was an astronomically curious soul and couldn’t help but study M33 intently on his own, writing:
“There is a suspicion that the nebula consists of exceedingly small stars. With this low power it has a nebulous appearance; and it vanishes when I put on the higher magnifying powers of 278 and 460.” He would continue to observe this grand galaxy again and again over the years, cataloging its various regions with their own separate numbers and keeping track of his findings: “The stars of the cluster are the smallest points imaginable. The diameter is nearly 18 minutes.”
Yet it would take a very special observer, one named Bill Parsons – the third Earl of Rosse – to become the very first to describe it as spiral. As he wrote of it:
“September 16, 1849. – New spiral: Alpha the brighter branch; Gamma faint; Delta short but pretty bright; Beta pretty distinct; Epsilon but suspected; the whole involved in a faint nebula, which probably extends past several knots which lie about it in different directions. Faint nebula seems to extend very far following: drawing taken.”
Quite the description indeed, since it would eventually lead to Rosse’s description of M33 being “…full of knots. Spiral arrangement. Two similar curves like an “S” cross in the center”, and to other astronomers discovering that these “spiral nebulae” were extra-galactic!
The location of Messier 33 in the Triangulum constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
Locating Messier 33:
While actually locating Messier 33 isn’t so difficult, seeing Messier 33 can be. Even though it is billed at nearly unaided eye magnitude, this huge, low surface brightness galaxy requires some experience with equipment and observing conditions or you may hunt forever in the right place and never find it. Let’s begin first by getting you in the proper area! First locate the Great Square of Pegasus – and its easternmost bright star, Alpha. About a hand span further east you will see the brightest star in Triangulum – Alpha.
M33 is just a couple of degrees (about 2 finger widths) west. Now, the most important part to understand is that you must use the lowest magnification possible, or you won’t be able to see the proverbial forest because of the trees. The image you see here at the top of the page is around a full degree of sky – about 1/3 the field of view of average binoculars and far larger than your average telescope eyepiece.
However, by using the least amount of magnification with a telescope you are causing M33 to appear much smaller – allowing it to fit within eyepiece field of view range. The larger the aperture, the more light it gathers and the brighter the image will be. The next thing to understand is M33 really is low surface brightness… Light pollution, a fine haze in the sky, moonlight… All of these things will make it difficult to find. Yet, there are places left here on Earth where the Triangulum Galaxy can be seen with no optical aid at all!
Enjoy your quest for M33. You may find it your first time out and it may be years before you see it in all its glory. But when you do, we guarantee you’ll never forget! Be sure to enjoy this video of the Triangulum galaxy too, courtesy of the European Southern Observatory:
Enjoy your quest for M33. You may find it your first time out and it may be years before you see it in all its glory. But when you do, we guarantee you’ll never forget!
And here are the quick facts on M33 to help you get started:
Object Name: Messier 33 Alternative Designations: M33, NGC 598, Triangulum Galaxy, Pinwheel Galaxy Object Type: Type Sc, Spiral Galaxy Constellation: Triangulum Right Ascension: 01 : 33.9 (h:m) Declination: +30 : 39 (deg:m) Distance: 3000 (kly) Visual Brightness: 5.7 (mag) Apparent Dimension: 73×45 (arc min)
