Mosaic self-portrait of Curiosity at the John Klein outcrop on Feb. 3, 2013 (NASA/JPL-Caltech/MSSS)
Although today Mars’ atmosphere is sparse and thin — barely 1% the density of Earth’s at sea level — scientists don’t believe that was always the case. The Red Planet likely had a much denser atmosphere similar to ours, long, long ago. So… what happened to it?
NASA’s Curiosity rover has now found strong evidence that Mars lost much of its atmosphere to space — just as many scientists have suspected. The findings were announced today at the EGU 2013 General Assembly in Vienna.
Curiosity’s SAM instrument (NASA/JPL-Caltech)
Curiosity’s microwave oven-sized Sample Analysis at Mars (SAM) instrument analyzed an atmosphere sample last week using a process that concentrates selected gases. The results provided the most precise measurements ever made of isotopes of argon in the Martian atmosphere.
Isotopes are variants of the same element with different atomic weights.
“We found arguably the clearest and most robust signature of atmospheric loss on Mars,” said Sushil Atreya, a SAM co-investigator at the University of Michigan.
SAM found that the Martian atmosphere has about four times as much of a lighter stable isotope (argon-36) compared to a heavier one (argon-38). This ratio is much lower than the Solar System’s original ratio, as estimated from measurements of the Sun and Jupiter.
The argon isotope fractionation provides clear evidence of the loss of atmosphere from Mars. (NASA/JPL)
This also removes previous uncertainty about the ratio in the Martian atmosphere in measurements from NASA’s Viking project in 1976, as well as from small volumes of argon extracted from Martian meteorites retrieved here on Earth.
These findings point to a process that favored loss of the lighter isotope over the heavier one, likely through gas escaping from the top of the atmosphere. This appears to be in line with a previously-suggested process called sputtering, by which atoms are knocked out of the upper atmosphere by energetic particles in the solar wind.
The solar wind may have helped strip Mars of its atmosphere over the course of many hundreds of millions of years (NASA)
Lacking a strong magnetic field, Mars’ atmosphere would have been extremely susceptible to atmospheric erosion by sputtering billions of years ago, when the solar wind was an estimated 300 times the density it is today.
These findings by Curiosity and SAM will undoubtedly support those made by NASA’s upcoming MAVEN mission, which will determine how much of the Martian atmosphere has been lost over time by measuring the current rate of escape to space. Scheduled to launch in November, MAVEN will be the first mission devoted to understanding Mars’ upper atmosphere.
Find out more about MAVEN and how Mars may have lost its atmosphere in the video below, and follow the most recent discoveries of the MSL mission here.
Canadian astronaut David Saint-Jacques prepares to simulate a spacewalk in NASA's Neutral Buoyancy Laboratory. Credit: NASA
A fire breaks out on the International Space Station while the orbiting complex is over Russian mission control. How, as an English-speaking astronaut, would you keep up with instructions?
The answer is years of Russian training. In between time in simulators, jet airplanes and underwater, neophyte astronauts spend hours learning to read Cyrillic characters and pronounce consonant-heavy words. In fact, one of NASA’s requirements for its astronauts now is to learn the Russian language.
“It’s taken very seriously in the program because of the level you need to reach if, God forbid, there was an emergency on board and there was a panicky discussion going on in Russian on the radio,” Canadian astronaut and medical doctor David Saint-Jacques told Universe Today. “Ultimately, you need to be fluent to be really useful in a situation like that.”
Saint-Jacques himself is no neophyte to language learning. A native francophone, he learned English in public school and really improved it when he was 15 and moved with his family to England for a year. Today he speaks it fluently. He also has some abilities in Japanese, a language he picked up while in that country for a junior academic position at a university.
David Saint-Jacques (left) with fellow Canadian astronaut trainee Jeremy Hansen. The two men were selected as astronauts in 2009. Credit: NASA
Now approaching four years as an astronaut trainee, Saint-Jacques told us how astronauts learn Russian. It’s a process that not only includes classroom instruction, but time living with a family in Moscow to really pick up on colloquialisms. Below is an edited interview.
What language training focuses on: “The point is not to write perfectly. The point is to communicate, similar to how businessmen learn languages. The emphasis for us is understanding spoken language, but the emphasis for us, the vocabulary, is different. I know all these obscure space hardware words and these crazy Russian space acronyms, but I may not know some of the flowers, for example. I can’t know everything.”
Basic Russian training: “We have Russian classes one-on-one with a Russian instructor. We get anything between one lesson every two weeks to three, four lessons a week, depending on how you accommodate the training schedule. Most astronauts want as much training as possible. It’s part of the requirements for basic training; you have to pass a certain competency test in Russian. There is a standard test that is used by the foreign affairs department, and so we do the same test. It’s a verbal test where you call the examiner on the phone and you have a discussion with them on the phone. If you pass a certain grade on that test, you are good to go.”
NEEMO 15 crew members from right to left: Shannon Walker (NASA), Steve Squyres (Cornell University), David Saint-Jacques (Canadian Space Agency), Takuya Onishi (Japanese Space Agency). Credit: NASA
Living in Russia: “You have to go to Russia at some point to learn the Soyuz spacecraft and the Russian segment of space station. That, of course, is in all in Russian. The training is in Russian and the books are in Russian. There are translators that could be there with you, but you don’t want to rely on an interpreter for class. It really hits home; the more you know, the better. You will be living there for months, and it’s a no-brainer: you have to speak Russian when you are going to Russia.”
Immersion: “I took some holidays there [in Russia] with my family. That’s one of the great things when you speak the language of the country; you have fun there. I try to hang out with any Russian cosmonaut that comes here to Houston to keep up with them. There are two other ways we can train: you can block two to three weeks to do an intensive Russian test where all you want to do [beforehand] is study Russian. Also, when you are assigned to a spaceflight, in the year before your spaceflight, they [NASA] will try to send you for a month and a half in Moscow in a family for total immersion. That makes most people bump up their Russian level quite a lot.”
Side benefits: “It makes you realize how at the end of the day, international relations is really a form of personal relations, and speaking a language is absolutely fundamental. It makes you graduate from having a professional experience to a life experience with the other person, the other country.”
Narrow-angle camera image of Titan from Cassini (NASA/JPL-Caltech/Space Science Institute)
In this image acquired on January 5, Cassini’s near-infrared vision pierced Titan’s opaque clouds to get a glimpse of the dark dune fields across a region called Senkyo.
The vast sea of dunes is composed of solid hydrocarbon particles that have precipitated out of Titan’s atmosphere. Also visible over Titan’s southern pole are the rising clouds of the recently-formed polar vortex.
For a closer look at Titan’s dunes (and to find out what the name Senkyo means) keep reading…
In the image above north on Titan is up and rotated 18 degrees to the right. It was taken using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.
The view was obtained at a distance of approximately 750,000 miles (1.2 million kilometers) from Titan.
Titan’s hydrocarbon dunes are found across the moon in a wide swath within 30 degrees of the equator and are each about a kilometer wide and tens to hundreds of kilometers long… and in some cases stand over 100 meters tall. (Source: Astronomy Now.)
Radar image of Titan’s dunes acquired on Jan. 13, 2007. This view is 160 kilometers (100 miles) high by 150 kilometers (90 miles) wide. (NASA/JPL)
Observations of the dunes with Cassini and ESA’s Huygens probe during its descent onto Titan’s surface have shown that the moon experiences seasonally-shifting equatorial winds during equinoxes, similar to what occurs over the Indian Ocean between monsoon seasons.
The name Senkyo refers to the Japanese realm of serenity and freedom from wordly cares and death… in line with the IAU convention of naming albedo features on Titan after mythological enchanted places.
Click here for an earlier view of Senkyo, and follow the Cassini mission here.
Color-composite of Titan made from raw Cassini images acquired on April 13, 2013 (added 4/17) NASA/JPL/SSI. Composite by J. Major.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
A fine recent view of Saturn as captured by Daniel Robb. (Credit & Copyright: Daniel Robb/Universe Today flickr community. All rights reserved).
A star party favorite is about to return to evening skies.
The planet Saturn can now be spied low to the southeast for northern hemisphere observers (to the northeast for folks in the southern) rising about 1-2 hours after local sunset this early April. That gap will continue to close until Saturn is opposite to the Sun in the sky later this month and rises as the Sun sets.
Opposition occurs on April 28th at 8:00 UT/4:00AM EDT. Saturn will shine at magnitude +0.1 and appear 18.8” in diameter excluding the rings, which give it a total angular diameter of 43”.
Saturn has just passed into the faint constellation Libra for 2013, although its springtime retrograde loop will bring it back into Virgo briefly. Both the 2013 and 2014 opposition will occur in Libra. Saturn will also pass 26’ from +4.2 Kappa Virginis on July 3rd as it moves back into Virgo while in retrograde before resuming direct motion back into Libra.
Saturn currently lies about 15° to the lower left of the +1.04 magnitude star Spica, also known as Alpha Virginis. Remember the handy saying to “Spike to Spica” from the handle of the Big Dipper asterism to locate the region. Another handy finder tip; stars twinkle, planet generally don’t. That is, unless your skies are extremely turbulent!
With an orbital period 29.46 years, Saturn moves slowly eastward year to year, taking 2-3 years to cross through each constellation along the ecliptic.
Oppositions are roughly 378 days apart and thus move forward on our calendar by about two weeks a year. Successive oppositions also move about 13° eastward per year.
Saturn as imaged by the author on June 11th, 2012.
Oppositions of the ringed planet are also currently becoming successively favorable for southern observers over the coming years. Saturn crossed into the southern celestial hemisphere some years back, and will be at its southernmost in 2018.
Saturn won’t pass north of the celestial equator again until early 2026. Saturn is 15 million kilometres farther from us than opposition last year as its moving toward aphelion in 2018.
Saturn will reach eastern quadrature this summer on July 28th and stand its highest south at sunset northern hemisphere observers. South of the equator, it will pass directly overhead or transit to the north. Saturn will be with us for most of the remainder of 2013 in evening skies until reaching solar conjunction on November 6th.
Looking at Saturn with binoculars, you’ll immediately note that something is amiss.
You’re getting a view similar to that of Galileo, who sketched Saturn as a sort of “double handled cup.” In fact, it wasn’t until 1655 that Christian Huygens correctly hypothesized that the rings of Saturn are a flat disk that is not physically in contact with the planet.
Huygens also discovered the large moon Titan. Shining at magnitude +8.5 and taking 16 days to orbit Saturn, Titan is the second largest moon in our solar system after Ganymede. Titan would easily be a planet in its own right if it orbited the Sun. Titan is easily picked out observing Saturn at low power through a telescope.
Saturn’s system of moons visible through a small telescope. orientation is for May 9th, 2013. (Created by the author using Starry Night).
Observing Saturn at slightly higher magnification, five moons interior to Titan become apparent. From outside in, they are Rhea, Dione, Tethys, Enceladus, and Mimas. Exterior to Titan is the curious moon of Iapetus. Taking 79 days to complete one orbit of Saturn, Iapetus varies in brightness from magnitude +11.9 to +10.2, or a factor of over 5 times. Arthur C. Clarke placed the final monolith in the book adaptation of 2001: A Space Odyssey on Iapetus for this reason. Close-ups from the Cassini spacecraft reveal a two-faced world covered with a dark leading hemisphere and a bright trailing side, but alas, no alien artifacts.
But the centerpiece of observing Saturn through a telescope is its brilliant and complex system of rings. The A, B, and C rings are easily apparent through a backyard telescope, as is the large spacing known as the Cassini Gap.
The rings are also currently tilted in respect to our Earthly vantage point. The rings were edge-on in 2009 and vanish when this occurs every 15-16 years.
This year, we see the rings of Saturn at a respectable 19 ° opening and widening. The rings will appear at their widest at over 25° in 2017 and then become edge-on again in 2025.
The average tilt (in degrees) of Saturn’s ring system as seen from Earth spanning 2008-2026. (Graph created by author).
The ring system of Saturn adds 0.7 magnitudes of overall brightness to the planet at opposition this year.
Another interesting optical phenomenon to watch for in the days leading up to opposition is known as the “opposition surge” in brightness, or the Seeliger effect. This is a retro-reflector effect familiar to many as high-beam headlights strike a highway sign. Think of the millions of particles making up Saturn’s rings as tiny little “retro-reflectors” focusing sunlight back directly along our line of sight. The opposition surge has been noted for other planets, but it’s most striking for Saturn when its rings are at their widest.
The disk of Saturn will cast a shadow straight back onto the rings around opposition and thus vanish from our view. The shadow across the back of the rings will then become more prominent over subsequent months, reaching its maximum angle at quadrature this northern hemisphere summer and then beginning to slowly slide back behind the planet again. A true challenge is to glimpse the disk of the through the Cassini gap in the rings… you’ll need clear steady skies and high magnification for this one!
It’s also interesting to note a very shallow partial lunar eclipse occurs with Saturn nearby just three days prior to opposition on April 25th. Saturn will appear 4° north of the Moon and it may be just possible to image both in the same frame.
The location of Saturn and the Full Moon during the April 25th partial eclipse. (Created by the author using Starry Night).
Saturn takes about 30 years to make its way around the zodiac. I remember just beginning to observe Saturn will my new 60mm Jason refractor as a teenager in 1983 as it crossed the constellation Virgo.Hey, I’ve been into astronomy for over one “Saturnian year” now… where will the next 30 years find us?
1st fully integrated Antares rocket stands firmly erect at seaside Launch Pad 0-A at NASA’s Wallops Flight Facility during exclusive launch complex tour by Universe Today. Maiden Antares test launch is scheduled for 17 April 2013. Later operational flights are critical to resupply the ISS. Credit: Ken Kremer (kenkremer.com) See Antares rollout and erection photo gallery below
1st fully integrated Antares rocket – decaled with huge American flag – stands firmly erect at seaside Launch Pad 0-A at NASA’s Wallops Flight Facility on 6 April 2013 following night time rollout. Maiden Antares test launch is scheduled for 17 April 2013. Later operational flights are critical to resupply the ISS. Credit: Ken Kremer (kenkremer.com).
See Antares rollout and erection photo gallery below[/caption]
For the first time ever, the new and fully integrated commercial Antares rocket built by Orbital Sciences was rolled out to its oceanside launch pad on a rather chilly Saturday morning (April 6) and erected at the very edge of the Eastern Virginia shoreline in anticipation of its maiden launch slated for April 17.
The inaugural liftoff of the privately developed two stage rocket is set for 5 p.m. from the newly constructed launch pad 0-A at the Mid-Atlantic Regional Spaceport (MARS) at NASA’s Wallops Flight Facility in Virginia.
And Universe Today was there! See my photo gallery herein.
Antares is the most powerful rocket ever to ascend near major American East Coast population centers, unlike anything before. The launch is open to the public and is generating buzz.
And this is one very cool looking rocket.
Antares rocket begins 1st ever rollout from processing hanger to NASA Wallops launch pad – beneath the Moon on 6 April 2013. Credit: Ken Kremer (kenkremer.com)
The maiden April 17 launch is actually a test flight dubbed the A-One Test Launch Mission.
The goal of the A-One mission is to validate that Antares is ready to launch Orbital‘s Cygnus capsule on a crucial docking demonstration and resupply mission to the International Space Station (ISS) as soon as this summer.
The 1 mile horizontal rollout trek of the gleaming white rocket from the NASA integration hanger to the pad on a specially designed trailer began in the dead of a frosty, windy night at 4:30 a.m. – and beneath a picturesque moon.
“We are all very happy and proud to get Antares to the pad today for the test flight,” Orbital ground operations manager Mike Brainard told Universe Today in an interview at Launch Complex 0-A.
The rocket was beautifully decaled with a huge American flag as well as the Antares, Cygnus and Orbital logos.
Raising Antares at NASA Wallops. Credit: Ken Kremer (kenkremer.com)
Antares was transported aboard the Transporter/Erector/Launcher (TEL), a multifunctional, specialized vehicle that also slowly raised the rocket to a vertical position on the launch pad a few hours later, starting at about 1 p.m. under clear blue skies.
This first ever Antares erection took about 30 minutes. The lift was postponed for several hours after arriving at the pad as Orbital personal monitored the continually gusting winds approaching the 29 knot limit and checked all pad and rocket systems to insure safety.
The TEL vehicle also serves as a support interface between the 133-foot Antares and the range of launch complex systems.
Antares transported atop aboard the Transporter/Erector/Launcher (TEL) beneath the Moon on 6 April 2013. Credit: Ken Kremer (kenkremer.com
Now that Antares stands vertical, “We are on a clear path to a launch date of April 17, provided there are no significant weather disruptions or major vehicle check-out delays between now and then,” said Mr. Michael Pinkston, Orbitals Antares Program Manager.
Antares is a medium class rocket similar to the Delta II and SpaceXFalcon 9.
For this test flight Antares will boost a simulated version of the Cygnus carrier – known as a mass simulator – into a target orbit of 250 x 300 kilometers and inclined 51.6 degrees.
Antares rolls up the ramp to Launch Complex 0-A at NASA’s Wallops Flight Facility on 6 April 2013. Credit: Ken Kremer (kenkremer.com)
The Antares first stage is powered by dual liquid fueled AJ26 first stage rocket engines that generate a combined total thrust of some 680,000 lbs. The upper stage features a Castor 30 solid rocket motor with thrust vectoring. Antares can loft payloads weighing over 5000 kg to LEO.
The Antares/Cygnus system was developed by Orbital Sciences Corp under NASA’s Commercial Orbital Transportation Services (COTS) program to replace the ISS cargo resupply capability previously tasked to NASA’s now retired Space Shuttle fleet.
Up Close with Antares beautifully decaled nose at NASA Wallops Pad 0-A. Credit: Ken Kremer (kenkremer.com)
Orbital’s Antares/Cygnus system is similar in scope to the SpaceX Falcon 9/Dragon system. Both firms won lucrative NASA contracts to deliver approximately 20,000 kilograms of supplies and equipment to the ISS.
The goal of NASA’s COTS initiative is to achieve safe, reliable and cost-effective transportation to and from the ISS and low-Earth orbit (LEO).
Orbital will launch at least eight Antares/Cygnus resupply missions to the ISS at a cost of $1.9 Billion
The maiden Antares launch has been postponed by about 2 years due to delays in laiunch pad construction and validating the rocket and engines for flight- similar in length to the start up delays experienced by SpaceX for Falcon 9 and Dragon.
Read my prior Antares story detailing my tour of the launch complex following the successful 29 sec hot-fire engine test that cleared the path for the April 17 liftoff – here & here.
Watch for my continuing reports through liftoff of the Antares A-One Test flight.
Learn more about Antares, SpaceX, Curiosity and NASA missions at Ken’s upcoming lecture presentations:
April 20/21 : “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus Orion, SpaceX, Antares, the Space Shuttle and more! NEAF Astronomy Forum, Suffern, NY
April 28: “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus the Space Shuttle, SpaceX, Antares, Orion and more. Washington Crossing State Park, Titusville, NJ, 130 PM
Only a few hundred feet of beach sand and a low sea wall separate the Wallops Island pad from the Atlantic Ocean and Mother Nature and potential catastrophe. Credit: Ken Kremer (kenkremer.com)Thumbs Up for Antares ! – from NASA Wallops Media team and Space journalists. Ken at right. Credit: Ken Kremer (kenkremer.com)
An artist's illustration of an asteroid retrieval spacecraft capturing a 7-meter-wide, 500-ton asteroid. Rick Sternbach/Keck Institute for Space Studies.
Rumors have been leaking out for over a week, but now according to Alan Boyle at NBC News’ Cosmic Log, a senior Obama administration official has confirmed that $100 million is being sought for NASA’s budget request for the coming fiscal year for work to allow a robotic spaceship to capture a small asteroid and park it near the Moon for astronauts to explore. The spacecraft would capture a 500-ton, 7- meter (25-foot) asteroid in 2019. Then using an Orion space capsule, a crew of about four astronauts would station-keep with the space rock in 2021 to allow for EVAs for exploration. This plan would accelerate NASA’s deep space missions with Orion and prepare crews for going to Mars.
NBC news quoted the official — who spoke on condition of anonymity because there was no authorization to discuss the plan publicly — as saying the mission would “accomplish the president’s challenge of sending humans to visit an asteroid by 2025 in a more cost-effective and potentially quicker time frame than under other scenarios.”
A week ago, Aviation Week reported that NASA was considering this asteroid mission, which was proposed by the Keck Institute for Space Studies last year. Keck’s proposal had a price tag of $2.6 billion, but no cost estimate for the space agency’s version has yet been released.
Then on April 5, the Associated Press quoted U.S. Sen. Bill Nelson, D-Florida, Nelson, chairman of the Senate science and space subcommittee, that President Obama is putting $100 million in planning money for the accelerated asteroid mission in the 2014 budget that comes out next week. The money would be used to find the right small asteroid.
“It really is a clever concept,” AP quoted Nelson said in a press conference in Orlando. “Go find your ideal candidate for an asteroid. Go get it robotically and bring it back.”
This would be the first time ever an object in space of this size would be manipulated in such a manner.
Donald Yeomans, who heads NASA’s Near Earth Object program, was quoted that while there are thousands of asteroids around 25-feet, finding the right one that comes by Earth at just the right time to be captured will not be easy. And once a suitable rock is found it would be captured with the space equivalent of “a baggie with a drawstring. You bag it. You attach the solar propulsion module to de-spin it and bring it back to where you want it.”
A 7- meter (25-foot) asteroid is not a threat to Earth because asteroids of that size would burn up in Earth’s atmosphere.
The official quoted by NBC said the plan has been under discussion for months, but after February’s meteor blast over Russia, the plan gained traction. The asteroid’s entry into Earth’s atmosphere and subsequent airblast injured more than 1,000 people, and sparked discussions about asteroid threats, including a series of congressional hearings. Congressional officials said they would support more funding to counter asteroid threats.
“This plan would help us prove we’re smarter than the dinosaurs,” NBC quoted said the official, referring to the asteroid that wiped out the dinosaurs and many other species 65 million years ago.
Comet P/Halley as seen on its last inner solar system passage on March 8th, 1986. (Credit: W. Liller/NASA GSFC/ International Halley Watch Large Scale Phenomena Network).
An interesting and largely unknown tale of ancient astronomy recently came our way while reading author and astrophysicist Mario Livio’s blog. The story involves the passage of the most famous of all comets.
It’s fascinating to consider ancient knowledge of the skies. While our knowledge of ancient astronomy is often sparse, we know that cultures lived and perished by carefully monitoring the passage of the heavens. A heliacal rising of Sirius might coincide with the impending flooding of the life-giving waters of the Nile, or the tracking of the solstices and equinoxes might mark the start of the seasons.
To the ancients, comets were “hairy stars” which appeared unpredictably in the sky. We generally attribute the first realization that comets are periodic to Sir Edmond Halley, who successfully utilized Newton’s laws of gravity and Kepler’s laws of planetary motion to predict the return of Halley’s Comet in 1758. Such a prediction was a vindication of science.
But an interesting tale comes to us from the 1st century CE that Rabbi & Jewish Scholar Yehoshua Ben Hananiah may have known something of “a star that appears every 70 years.” The tale, as told in the Horayoth (rulings) of the Talmud and described in Mr. Livio’s blog is intriguing:
Rabbi Gamliel and Rabbi Yehoshua went together on a voyage at sea. Rabbi Gamliel carried a supply of bread. Rabbi Yehoshua carried a similar amount of bread and in addition a reserve of flour. At sea, they used up the entire supply of bread and had to utilize Rabbi Yehoshua’s flour reserve. Rabbi Gamliel then asked Rabbi Yehoshua: “Did you know that this trip would be longer than usual, when you decided to carry this flour reserve?” Rabbi Yehoshua answered: “There is a star that appears every 70 years and induces navigation errors. I thought it might appear and cause us to go astray.”
The Rabbi’s assertion is a fascinating one. There aren’t a whole lot of astronomical phenomena on 70 cycles that would have been noticeable to ancient astronomers. With an orbital period of 75.3 years, Halley’s Comet seems to fit the bill the best. The earliest confirmed description of Halley’s comes from Chinese astronomers during its 240 BCE passage. Later subsequent passages of the comet through the inner solar system were noted by the Babylonians in 164 & 87 BCE.
Of course, there’s no further evidence that ancient scholars identified those passages as the same comet. Some great comets such as Hale-Bopp seen in 1997 and this year’s anticipated Comet C/2012 S1 ISON are on orbits spanning thousands of years that outlast most Earthly civilizations.
Mr. Livio also notes that historical knowledge of ancient apparitions of Halley’s may have been accessible to the Great Knesset scholars during the Babylonian exile of the 6th century BCE.
One of the chief objections raised to the Halley hypothesis is the circumstances of the appearance of Halley’s Comet in the Rabbi’s lifetime. Remember, most folks didn’t live for 70 years in the 1st century. Any tales of a periodic comet would have been handed down by generations. You would be lucky to see Halley’s Comet once in your lifetime. Plus, not all apparitions of Halley’s Comet are favorable. For example, Halley’s was bright enough to induce “comet hysteria” with the public in 1910. In contrast, few northern hemisphere members of the general public got a good view of it during its 1986 passage.
Medieval woodcut depicting the supposed destructive influence of a 4th century comet. (Credit: Stanilaus Lubienietski’s Theatrum Cometicum, Amsterdam 1668).
Halley’s Comet was visible on and around January 25th, 66 CE during the Rabbi’s lifetime. However, the Rabbi would have been in his 20’s and have been a student (and not yet a Rabbi) himself. One can imagine that if he was fearful of a “false star” leading them astray, he must’ve known that the 70 year period was just about neigh.
The 66 CE apparition of Halley’s Comet would have appeared around the time of the Jewish Rebellion and just four years before the destruction of the Second Temple in Jerusalem by the Romans in 70 CE.
One other possible astronomical culprit has been cited over the years. The classic variable star Mira (Omicron Ceti) currently has a 332 day cycle which ranges from magnitude +3.5 to below naked eye visibility at +8.6 to +10.1. The variability of Mira was first discovered by astronomer David Fabricius on August 3rd 1596. There are suggestions that ancient Chinese and Babylonian astronomers may have known of this “vanishing star”.
The variable star Mira as imaged by the Hubble Space Telescope. (Credit: NASA/STScl/Margarita Karovska at the Harvard-Smithsonian Center for Astrophysics).
Mira is expected to reach maximum for 2013 from July 21st to 31st.
Not all maxima for Mira are of equal brightness. Mira can peak anywhere from magnitude +2.0 to +4.9 (a 15-fold difference) and there’s evidence to suggest it may have been brighter in the past. Astronomer Philippe Veron noted in 1982 that a larger oscillation period of 60 years for the peak maxima of Mira falls just a decade short of Rabbi Yehoshua’s mention of an errant star.
Whatever the case, its fascinating to consider what celestial object might’ve been referred to, and how many other astronomical tales might be awaiting discovery in ancient texts. We’ve got lots of comets to ponder this year as Comet PanSTARRS, Lemmon, and ISON grace our skies in 2013. Halley’s will make its next visit to the inner solar system in 2061. I’ll open it up to you, the astute Universe Today reading public; was the Rabbi’s Star a comet, a variable star, a meteor storm, or none of the above?
Halley’s Comet as seen from latitude 30 north on the morning of July 31st, 2061. (Created by the author using Starry Night software).
-Dr. Mario Livio blogs at A Curious Mind. Be sure to check out his new bookBrilliant Blunders: From Darwin to Einstein – Colossal Mistakes by Great Scientists That Changed Our Understanding of Life in the Universe out on May 14th!
Curiosity and Mount Sharp - Parting Shot ahead of Solar Conjunction. Enjoy this parting view of Curiosity's elevated robotic arm and drill are staring at you - back dropped with her ultimate destination - Mount Sharp - in this panoramic vista of Yellowknife Bay basin snapped on March 23, Sol 223, by the rover's navigation camera system. The raw images were stitched by Marco Di Lorenzo and Ken Kremer and colorized. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/KenKremer (kenkremer.com). See video below explaining Mars Solar Conjunction
Curiosity and Mount Sharp – Parting Shot ahead of Mars Solar Conjunction
Enjoy this parting view of Curiosity’s elevated robotic arm and drill staring at you; back dropped with her ultimate destination – Mount Sharp – in this panoramic vista of Yellowknife Bay basin snapped on March 23, Sol 223, by the rover’s navigation camera system. The raw images were stitched by Marco Di Lorenzo and Ken Kremer and colorized. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/KenKremer (kenkremer.com)
See video below explaining Mars Solar Conjunction[/caption]
Earth’s science invasion fleet at Mars is taking a break from speaking with their handlers back on Earth.
Why ? Because as happens every 26 months, the sun has gotten directly in the way of Mars and Earth.
Earth, Mars and the Sun are lined up in nearly a straight line. The geometry is normal and it’s called ‘Mars Solar Conjunction’.
Conjunction officially started on April 4 and lasts until around May 1.
From our perspective here on Earth, Mars will be passing behind the Sun.
Watch this brief NASA JPL video for an explanation of Mars Solar Conjunction.
Therefore the Terran fleet will be on its own for the next month since the sun will be blocking nearly all communications.
In fact since the sun can disrupt and garble communications, mission controllers will be pretty much suspending transmissions and commands so as not to inadvertently create serious problems that could damage the fleet in a worst case scenario.
Right now there are a trio of orbiters and a duo of rovers from NASA and ESA exploring Mars.
The spacecraft include the Curiosity (MSL) and Opportunity (MER) rovers from NASA. Also the Mars Express orbiter from ESA and the Mars Odyssey (MO) and Mars Reconnaissance Orbiter (MRO) from NASA.
Geometry of Mars Solar Conjunction
Because several of these robotic assets have been at Mars for nearly 10 years and longer, the engineering teams have a lot of experience with handling them during the month long conjunction period.
“This is our sixth conjunction for Odyssey,” said Chris Potts of JPL, mission manager for NASA’s Mars Odyssey, which has been orbiting Mars since 2001. “We have plenty of useful experience dealing with them, though each conjunction is a little different.”
But there is something new this go round.
“The biggest difference for this 2013 conjunction is having Curiosity on Mars,” Potts said. Odyssey and the Mars Reconnaissance Orbiter relay almost all data coming from Curiosity and the Mars Exploration Rover Opportunity, as well as conducting the orbiters’ own science observations.
The rovers and orbiters can continue working and collecting science images and spectral data.
But that data will all be stored in the on board memory for a post-conjunction playback starting sometime in May.
Learn more about Curiosity’s groundbreaking discoveries and NASA missions at Ken’s upcoming lecture presentations:
April 20/21 : “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus Orion, SpaceX, Antares, the Space Shuttle and more! NEAF Astronomy Forum, Suffern, NY
April 28: “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus the Space Shuttle, SpaceX, Antares, Orion and more. Washington Crossing State Park, Titusville, NJ, 130 PM
A montage of the six Green Pea galaxies that University of Michigan astronomy researchers studied. Image credit: Anne Jaskot
Today, we see an unobstructed view of the cosmos in all directions. But, a time existed near the Big Bang when the space between galaxies was an opaque fog where nothing could be seen. And according to two University of Michigan researchers, rare Green Pea galaxies, discovered in 2007, could offer clues into a pivotal step, called reionization, in the Universe’s evolution when space became transparent.
Reionization occurred just a few million years after the Big Bang. During this time, the first stars were beginning to blaze forth and galaxies. Astronomers believe these massive stars blasted the early universe with high-energy ultraviolet light. The UV light interacted with the neutral hydrogen gas it met, scraping off electrons and leaving behind a plasma of negatively charged electrons and positively charged hydrogen ions.
“We think this is what happened but when we looked at galaxies nearby, the high-energy radiation doesn’t appear to make it out. There’s been a push to find some galaxies that show signs of radiation escaping,” Anne Jaskot, a doctoral student in astronomy, says in a press release.
In findings released in the current edition of the Astrophysical Journal, Jaskot and Sally Oey, an associate professor of astronomy, the astronomers focused on six of the most intensely star-forming Green Pea galaxies between one billion and five billion light-years from Earth. The galaxies are compact and closely resemble early galaxies. The objects are thought to be a type of Luminous Blue Compact Galaxy, a type of starburst galaxy where stars are forming at prodigious rates. They were discovered in 2007 by volunteers with the citizen science project Galaxy Zoo. Named “peas” because of their fuzzy green appearance, the galaxies are very small. Scientists estimate that they are no larger than about 16,000 light-years across making them about the size of the Large Magellanic Cloud, a irregular galaxy near our Milky Way Galaxy.
Using data from the Sloan Digital Sky Survey, Jaskot and Oey studied the emission lines from the galaxies to determine how much light was absorbed. Emission lines tell astronomers not only what elements are present in the stars but also much about the intervening space. By studying this interaction, the researchers determined that the galaxies produced more radiation than observed, meaning some must have escaped.
“An analogy might be if you have a tablecloth and you spill something on it. If you see the cloth has been stained all the way to the edges, there’s a good chance it also spilled onto the floor,” Jaskot said. “We’re looking at the gas like the tablecloth and seeing how much light it has absorbed. It has absorbed a lot of light. We’re seeing that the galaxy is saturated with it and there’s probably some extra that spilled off the edges.”
