In a study led by Dr. Christian Wolf and reported in the Publications of the Astronomical Society of Australia, a black hole was just discovered that is consuming material at a record-breaking rate of one star every 2-3 days.
Dr. Wolf and his team found this black hole by searching for objects in the sky that do not move. Hyper-achieving black holes are very small and point-like, so can often be initially confused with stars. Side-by-side, the distinguishing feature is that only the stars are near to us. The implication is that over a period of years or decades only the stars will move across the sky.
But, once a distant object with an "active" black hole is found, what is going on there? Why is it shining so brightly?
One can imagine an assembly line that carries stars along it one-by-one. Each time a star drops off of the conveyer belt "at the end of the line," the star collides with the hot and fast moving collection of gas surrounding the black hole. This "accretion disk" takes in the doomed star which by now is stretching like taffy and heating up to the point that it emits X-rays and gamma-rays. Some of this high energy radiation shoots out of the black hole.
As a result of emitting radiation, it gives us a chance to find and study these objects which otherwise would be utterly dark.
This black hole that was just found shines with a brightness that is equal to about 10,000 times that of all the stars in the Milky Way combined. If we could relocate this object to the center of the Milky Way, then this monstrous object would appear in our night sky with a brightness equal to ten full moons.
This would disrupt the lives of nocturnal creatures on our planet, but this problem would be minor. The incident X-ray emission would be sufficient to irradiate all life on Earth. Fortunately, the black hole resident in the center of our galaxy is relatively calm. Indeed gluttony is an attribute of supermassive black holes typically associated only with sources existing very far away and a long time ago.
I am pleased to announce a little history of science publication. It is not a scholarly article, but one for a broader readership. It appeared in issue 60 of Nautilus magazine (freely available) just two days ago.
Check it out. I can't claim credit for the artwork (which I borrowed for this post) or the title—they come from Nautilus. The rest, however, is mine.
Marvellous Mars drawing workshop at Castletown House Co Kildare Ireland. 42 drawings based on images from the planet Mars. All toward understanding the planet and the ongoing explorations.
Castletown House is a Georgian palace set in a magnificent landscape in Co Kildare. The building is full of grace and elegance of times long past . That splendour coupled with all that is required of a building for public events makes Castletown House a special place. It was a pleasure to be invited to do a workshop in this excellent venue. Particularly timely as it was on the eve of the launch of NASA's InSight mission. The evening was set up for my Marvellous Mars drawing workshop. The audience were families , mams, dads and children, a perfect combination.
It was a beautiful, with late warm sunshine , a powder blue sky over the greenest of green trees. Flowers, shrubs and land stretching out over 120 acres that seemed to go on forever It occurred to me that perhaps my audience might be small due to the pleasant weather and bank holiday. However 42 people arrived , sat down and participated with lots of energy .
This activity was born out of my enthusiasm for the images sent back to Earth from various missions. Amongst them all, my favourite camera in space is the HiRise on Mars Reconnaissance Obiter (MRO). The images are available in The Beautiful Mars Project . Also included are mini stories about Curiosity, InSight, ExoMars and Mars 2020. It was opportune that NASA's latest Mars mission InSight was launching the next day . The audience loved the fact that the CubeSats accompanying InSight were called WALL - E and EVE after characters in a Disney/ Pixar animated movie.
During my presentation I try to provide a balance between ESA and NASA missions. It is always important to me to emphasise the collaborations between space agencies and scientists. Being in the now by speaking about current, and proposed space missions adds to the excitement. It would have been brilliant to know at the time, about the latest news regarding a drone helicopter due to cruise the surface of the planet on the Mars2020 mission. Bob Trembely wrote about that here recently if you missed it.
In order to engage my audience further I brought along a model of Mars which I made some years ago. Having Mars in the room helps when talking about the planets unique features. My model used to be a football in a men's fashion shop window. A little persuasion helped me acquire it after the sale ended.
It took a lot of work to make it into Mars. Polystyrene is easy to carve but getting all the features in the right place on a sphere is not easy. At first I was using a large format book by Giles Sparrow ( Mars at New View of the Red Planet). Wonderful images of the planet, but difficult to transfer flat maps to a 3 dimensional object. So then I discovered Mars Globe for iPhone and viola the planets aspects could be viewed in my hand from all angles. Roll it around, view it from the poles to see their shapes. I used it look at a feature, make the feature, move along the curve of the sphere, make it and so on.
This app was very useful in pinpointing the landing areas of previous missions and where features were in relation to each other. Having Mars in my hand was just wonderful .InSight is now added to the model , ExoMars and Mars2020 will follow.
Beautiful drawing of an impact crater on Mars by a young lady. My homemade model of Mars stands behind the children.
Some of the drawings produced that evening were most impressive . Impact craters were very popular as usual. Several children drew ESA's Trace Gas Obiter. It's latest image of Korolev Crater was avoided by everyone due to its complexity. Martian Dust Devils were attempted by children , mams and dads.
Yes, this boy did an impactful drawing of a Martian Dust Devil. He also holds a drawing of sand moving across the surface of the planet.
The Universe is my Playground stickers (from ESO) were given to everyone. I was pleased to be able to give ESA / ROSCOSMOS Trace Gas Orbiter (Part of ExoMars) posters to the participants who made an effort to draw this relatively recent arrival at the red planet.
The original version of this article first appeared in The Tablet in May, 2004, announcing the transit as an upcoming event; we ran a version here on the blog in June, 2015.
“There’s a little black spot on the Sun today...” In the Police song “King of Pain” these words evoke an alienating sense of remoteness. But on the morning of June 8, 2004, a much larger spot was visible crossing the Sun, an event that occurs but twice a century; when it happened in the eighteenth century, it changed human history.
Transit of Venus, 2004, imaged by Ron Dantowitz from the roof of the Papal Palace in Castel Gandolfo
A “transit” occurs when we see one astronomical object appear to move in front of another. Since Venus orbits between us and the Sun, you might expect it to transit the Sun rather frequently. But the Sun is small, as seen from Earth, and the orbit of Venus is tilted slightly compared to ours, so Venus usually appears to pass above or below the Sun. It’s only when our orbits are precisely lined up that the black spot of Venus’ nighttime side stands out against the Sun’s brilliant disk. This happens in pairs, 8 years apart, about every 130 years. The last pair of transits were in 1874 and 1882.
The Venus transit was merely an astronomical curiosity when first observed, by the English cleric Jeremiah Horrocks in 1639. But in 1716, Edmund Halley (of comet fame) pointed out that the transits of Venus predicted for 1761 and 1769 provided a unique opportunity to make a fundamental measure of the universe.
By the 18th century, the observations of planets and Kepler’s laws describing their motions merely allowed astronomers to compute the relative distances between planets. Only if you could actually count the number of miles between any two planets, could the distances to all the other planets be worked out. But how do you make that one definitive measure?
Halley realized that a Venus transit let you to do just that. It’s a matter of parallax. If two people observe the same transit from two different vantage points, they’ll see Venus crossing the Sun in two slightly different paths. The distance between those paths, if you know how many miles apart the observers are, can then be translated into how many miles away Venus is from us and from the Sun.
Thus, to measure the parallax of Venus you have to have at least two observers in well-mapped positions, as far as possible from each other. Getting to distant locations and measuring their positions accurately was in itself was a challenge in the 18th century. The more people observing, the better you could average out these uncertainties. By the middle of the century, an international group of astronomers were preparing the observations.
Unfortunately, they didn’t count on the vagaries of international politics. By the 1761 transit, France and Britain were engaged in the Seven Years War, raging from India to North America. When the Astronomer Royal’s assistant, Charles Mason, left for India he never got farther than the English Channel before being attacked by the French fleet. (His ship escaped back to England, and eventually he sailed to South Africa.) Likewise, the French astronomer Le Gentil got to India only to find that his goal, the French colony at Pondicherry, had fallen to the English; on the day of the transit, his boat was still out at sea, for fear of capture.
With all these difficulties, and the challenge of observing a very dark spot against a very bright Sun, the results of the first set of observations were less than satisfactory.
It was another eight years before a second set of observations could be made. Mason and his surveyor assistant, Jeremiah Dixon, came home by way of the North America colonies, where they took the time to survey the boundary between the northern and southern (slave-holding) American colonies, known to this day as the Mason-Dixon line. Le Gentil stayed in India to wait out the next event. And, after the end of the war, the Royal Astronomer decided to lease a ship, the Endeavour, from the Royal Navy for the next expedition to the South Seas.
The 1769 event was observed at 77 different locations around the world. Le Gentil, in India, saw nothing but clouds; having missed both events, he returned to France only to find that he’d been declared dead and his property distributed among his heirs. But other observers (including Jesuits in China and an arctic expedition lead by Fr. Maximillian Hell of Vienna) had greater success. The results were surprising: the solar system turned out to be some ten times bigger than most astronomers had expected.
The astronomical significance of this measurement did not stop at the solar system. Knowing how far the Earth travels as it goes around the Sun allows you to use the same parallax trick; the positions of nearby stars appear to move ever so slightly compared to more distant stars when observed from one side of the Earth’s orbit to the other. In this way, distances to stars could be measured, and the scale of the galaxy determined. This was the first step in calculating the distance to other galaxies, and clusters of galaxies, a measurement that forms an active part of astronomy even today. It’s a big, empty universe out there.
The success of the 1769 observations had other ramifications. The young Navy lieutenant assigned to keep an eye on the Endeavour -- James Cook -- started a tradition of combined naval and scientific exploration of distant seas, from Australia to Hawaii, which foreshadowed Darwin and the Beagle and indeed the military pilots who flew the Apollo missions to the Moon.
Today, spacecraft make these measurements far more accurately. But anyone equipped to look at the Sun can recreate those historical observations. (Use all the same care you'd use for a solar eclipse, as in 1999: proper filters, or pinhole projection. Don't look directly at the Sun, and don't look too long even with filters -- stop before it hurts!)
Take a moment on the morning of June 8 to appreciate this rare dance of the planets. There is a peculiarly human delight at predicting and seeing this conjunction, and knowing its historical and scientific significance. As Sting sang: there’s a little black spot on the Sun today; that’s my soul up there.
The transit in 2004 was observed from our rooftop in Castel Gandolfo with a group sponsored by Sky and Telescope. The 2012 transit was observed there by our Vatican Observatory Summer School
Transit observers from the Sky and Telescope group of 2004, on the roof of the Papal Palace
Mars and Saturn agree that they rather like the early morning sky, and have decided to stay there forever... or so it seems...
Southern sky at 5:00 AM, May 15, 2018. Credit: Stellarium / Bob Trembley.
Jupiter just past opposition, is slowly leaving the morning planets and making its way towards being visible only in the evenings.
Southeastern sky at 10:00 PM, May 15, 2018. Credit: Stellarium / Bob Trembley.
I was playing with the equatorial grid feature of Stellarium and noticed how close Polaris was to the North Celestial Pole.
North Celestial Pole at 10:00 PM, May 15, 2018. Credit: Stellarium / Bob Trembley.
So, of course, I HAD to see how the South Celestial Pole looked... and I noticed the the southern hemisphere doesn't have a convenient star near the pole - which led me to find this article on the One-Minute Astronomer about how to find the South Celestial Pole.
South Celestial Pole at 5:00 PM, May 15, 2018. Credit: Stellarium / Bob Trembley.
The Moon from May 15-21, 2018. Visualizations by Ernie Wright
The Moon is new on the 15th, and joins Venus in the western sky near sunset as a thin waxing crescent on the 17th. The Moon will be high in the western sky after sunset on the 20th &21st.
The Moon and Venus in the western sky at 9:00 PM, May 17, 2018. Credit: Stellarium / Bob Trembley.
The Moon in the western sky at 10:00 PM, May 20, 2018. Credit: Stellarium / Bob Trembley.
Although there is some impressive coronal loop activity along the Sun's equator, the Sun has been spot-free for a day. Coronal holes remain at both poles with a diffuse hole along the equator. The solar wind speed is 357 km/sec, with a density of 4.0 protons/cm3. SpaceWeather.com says: "NOAA forecasters estimate a 60% chance of G1-class geomagnetic storms on May 17th when a stream of solar wind hits Earth's magnetic field. The gaseous material is flowing from a southern hole in the sun's atmosphere. High-latitude sky watchers should be alert for auroras and, of course, STEVE."
Compared to the last few weeks, there have been only a few prominences in the Sun's chromosphere over the last couple days.
Professor Stephen Hawking wrote one final paper which is published posthumously. In this new paper, Hawking and collaborator Professor Thomas Hertog conclude that our Universe sprung from a larger state or "multiverse" that is not infinite.
Let us understand what this is all about by stepping back about 13.7 billion years in time. In these early days there is various evidence that our young Universe experienced a rapid period of growth called "inflation." A very short time later, the inflation stopped and calmed down into the more gentle mode of expansion plus acceleration we see in our Universe today. But what is the situation beyond our Universe, in the multiverse, and how does it behave?
The prevailing idea is that inflation is a normal attribute in the multiverse, such that the multiverse is expanding all the time at exponential rates in state called "eternal" inflation.
From time to time, a universe such as our own emerges, and potentially even an infinite number of universes arise each with a different set of physical laws. But Professor Hawking was never a fan of the multiverse.
Hawking and Hertog set out to understand better this significant problem on the starting assumption that relativity physics was not important in the early periods of inflation. As such, they were justified to consider that only quantum theory was the dominant physics. They then introduced the approximation that the multiverse is empty, meaning that it has no matter or energy. They went on to impose a shape of this larger entity, and removed the dimension of time from their equations altogether, as time has no meaning in a state not subject to relativity physics.
Their conclusion is that we still live a multiverse, but it is no longer infinite with infinite physics and infinite possibilities. But, as Douglas Adams tells us, it is still "mind-bogglingly big."
One of the more inflammatory subjects in the United States in regard to faith and science is evolution. The mere mention of the topic can lead to a combative atmosphere with little hope for anything healthy emerging. What I find a bit surprising is the number of brother priests who think that evolution is somehow against Catholicism. Whether it be the Catechism of the Catholic Church when it says that "methodological research in all branches of knowledge, provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with faith" (CCC 159), Pius XII stating that the material origins of our body evolving from preexisting matter is not against Scripture (Humani Generis 36), St. John Paul II stating the evolution is more than a hypothesis (Message to the Pontifical Academy of Sciences: On Evolution 4), or Benedict XVI stating that it is absurd to think that Biblical creation and evolution are at odds with one another (Question and Answer with German clergy, July 24, 2007), there still persists an ardent resistance in some corners to embracing the science of evolution.
This leads to a logical question, With the clarity of our pontiffs of the past (along with Pope Francis), why is there still doubt about evolution - especially in the United States? Part of the answer to this question has to do with the diversity of Biblical interpretation that exists depending on which faith tradition one comes from. Faiths that emphasize a more literalist interpretation of the Bible struggle with the idea of evolution while faith traditions, such at Catholicism, that seek to understand the literal sense of Scripture (applying a number of senses to Scripture that are both historical and spiritual) are much more open to embracing evolution. Just as I have encountered a wide variety of Atheists in my priesthood (those who are very open to faith and others that are very closed to faith) so, too, does one find many types of Christians, especially when it comes to evolution.
Given the foundational disagreements as to how to interpret Scripture, I fear that it will take something miraculous to bring all Christian faiths to a unified understanding of how to approach this important question. The reason I hold out hope that a unified vision may someday occur is that, in both faith and science, the starting points are rooted in objective sources. Whether it be fossil records, genetic markers, the Old Testament, or the New Testament, these primary sources, both biblical and scientific, give natural parameters for a dialogue to begin. As a devout Catholic, I have faith that a dialogue rooted in civility, charity, honesty, a pursuit of truth, and an openness to the Holy Spirit will lead us away from a divisive atmosphere to one of collaboration.
Below are a series of videos that look at the question of evolution and the supposed fight between faith and science. I find in these videos a sober approach to the question that opens one's heart to truth instead of devolving into sophomoric spitting matches of rhetorical one-upsmanship. The first is from the AAAS's program Science for Seminaries, taking a closer look at what it means to call evolution a theory from the standpoint of science. The next two videos are from the project Exploring Science in Seminaries, looking at the proper relationship between faith and science by summarizing key Church documents on this matter. Lastly, I also offer two videos that explore the relationship between faith, science, and politics. The first is a wonderful video from the Anglican Biblical Scholar NT Wright, explaining the history of political thought in relation to evolution. The second is another AAAS video, exploring the historical origins of the fight between faith and science in the United States. Enjoy!
NT Wright Lecturing on the Sacraments of Baptism and Eucharist at the Calvin Institute of Christian Worship.
AAAS's Video: What Makes Evolution A Theory?
The myth of the clash between faith and science
Church Documents on Faith and Science
NT Wright on Evolution
Historical origins of "The Conflict Thesis" in the United States.
NASA's Mars Helicopter, a small, autonomous rotorcraft, will travel with the agency's Mars 2020 rover, currently scheduled to launch in July 2020, to demonstrate the viability and potential of heavier-than-air vehicles on the Red Planet. Credits: NASA/JPL-Caltech
NASA is sending a helicopter to Mars.
The Mars Helicopter, a small, autonomous rotorcraft, will travel with the agency’s Mars 2020 rover mission, currently scheduled to launch in July 2020, to demonstrate the viability and potential of heavier-than-air vehicles on the Red Planet.
“NASA has a proud history of firsts,” said NASA Administrator Jim Bridenstine. “The idea of a helicopter flying the skies of another planet is thrilling. The Mars Helicopter holds much promise for our future science, discovery, and exploration missions to Mars.”
Animation of Mars helicopter and Mars 2020 rover. Credits: NASA/JPL-CalTech
U.S. Rep. John Culberson of Texas echoed Bridenstine’s appreciation of the impact of American firsts on the future of exploration and discovery.
“It’s fitting that the United States of America is the first nation in history to fly the first heavier-than-air craft on another world,” Culberson said. “This exciting and visionary achievement will inspire young people all over the United States to become scientists and engineers, paving the way for even greater discoveries in the future.”
Started in August 2013 as a technology development project at NASA’s Jet Propulsion Laboratory (JPL), the Mars Helicopter had to prove that big things could come in small packages. The result of the team’s four years of design, testing and redesign weighs in at little under four pounds (1.8 kilograms). Its fuselage is about the size of a softball, and its twin, counter-rotating blades will bite into the thin Martian atmosphere at almost 3,000 rpm – about 10 times the rate of a helicopter on Earth.
“Exploring the Red Planet with NASA’s Mars Helicopter exemplifies a successful marriage of science and technology innovation and is a unique opportunity to advance Mars exploration for the future,” said Thomas Zurbuchen, Associate Administrator for NASA's Science Mission Directorate at the agency headquarters in Washington. “After the Wright Brothers proved 117 years ago that powered, sustained, and controlled flight was possible here on Earth, another group of American pioneers may prove the same can be done on another world.”
The helicopter also contains built-in capabilities needed for operation at Mars, including solar cells to charge its lithium-ion batteries, and a heating mechanism to keep it warm through the cold Martian nights. But before the helicopter can fly at Mars it has to get there. It will do so attached to the belly pan of the Mars 2020 rover.
“The altitude record for a helicopter flying here on Earth is about 40,000 feet. The atmosphere of Mars is only one percent that of Earth, so when our helicopter is on the Martian surface, it’s already at the Earth equivalent of 100,000 feet up,” said Mimi Aung, Mars Helicopter project manager at JPL. “To make it fly at that low atmospheric density, we had to scrutinize everything, make it as light as possible while being as strong and as powerful as it can possibly be.”
Once the rover is on the planet’s surface, a suitable location will be found to deploy the helicopter down from the vehicle and place it onto the ground. The rover then will be driven away from the helicopter to a safe distance from which it will relay commands. After its batteries are charged and a myriad of tests are performed, controllers on Earth will command the Mars Helicopter to take its first autonomous flight into history.
“We don’t have a pilot and Earth will be several light minutes away, so there is no way to joystick this mission in real time,” said Aung. “Instead, we have an autonomous capability that will be able to receive and interpret commands from the ground, and then fly the mission on its own.”
The full 30-day flight test campaign will include up to five flights of incrementally farther flight distances, up to a few hundred meters, and longer durations as long as 90 seconds, over a period. On its first flight, the helicopter will make a short vertical climb to 10 feet (3 meters), where it will hover for about 30 seconds.
As a technology demonstration, the Mars Helicopter is considered a high-risk, high-reward project. If it does not work, the Mars 2020 mission will not be impacted. If it does work, helicopters may have a real future as low-flying scouts and aerial vehicles to access locations not reachable by ground travel.
“The ability to see clearly what lies beyond the next hill is crucial for future explorers,” said Zurbuchen. “We already have great views of Mars from the surface as well as from orbit. With the added dimension of a bird’s-eye view from a ‘marscopter,’ we can only imagine what future missions will achieve.”
Mars 2020 will launch on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida, and is expected to reach Mars in February 2021.
The rover will conduct geological assessments of its landing site on Mars, determine the habitability of the environment, search for signs of ancient Martian life, and assess natural resources and hazards for future human explorers. Scientists will use the instruments aboard the rover to identify and collect samples of rock and soil, encase them in sealed tubes, and leave them on the planet’s surface for potential return to Earth on a future Mars mission.
The Mars 2020 Project at JPL in Pasadena, California, manages rover development for the Science Mission Directorate at NASA Headquarters in Washington. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, is responsible for launch management.
People are believers. A couple of years ago National Geographic did a story with the headline “The World’s Newest Major Religion: No Religion”, which addressed how “the religiously unaffiliated, called ‘nones’, are growing significantly”. However, even the religiously unaffiliated are often believers.
Many of my Astronomy 101 students are ‘nones’. When the class touches on early ideas about how the universe works, ideas that might involve religious concepts such as the god Helios being the reason for the rising and setting of the sun, students will often volunteer their lack of belief in any religion, and marvel at how people ever relied on ideas like Helios to explain the world. But when the class moves into the subject of intelligent life on other worlds (where we learn about the historical and scientific track record regarding the idea of intelligent extraterrestrials—and it is not a good track record, as I have recently discussed at length) a surprising number of students reveal a belief in things with little more scientific or logical basis than Helios.
At the end of the “extraterrestrials” unit, I invite the students to dive into the deep end: to find a good “true” story about aliens (or an Earth-bound equivalent, like Sasquatch or ghosts), and give a presentation on what they find, and on whether they believe what they find. This little project is supposed to be an exercise in critical thinking. However, a surprising number express either (a) that they in fact found the material they turned up to be convincing, and that the stories of abducting space aliens, ghosts, or lizard people, are true; or (b) that they are open to believing what they found. This is despite what we cover in class, and despite the unbelievably weak “proof” offered by any of these stories. Visitors to public nights at our observatory have offered similarly uncritical views—or subscribe to other ideas that lack much scientifically persuasive power, like the idea that the Apollo moon landings were hoaxes. Clearly a society of increasing numbers of ‘nones’ is not necessarily a society that will be dominated by a sort of cool, scientific rationalism.
Sasquatch is a particularly interesting case for the scientist. Sasquatch is a really popular idea—a perennial student choice for the project. The internet is full of videos purporting to show a multitude of Sasquatches here and there, all of which somehow have managed to elude the scrutiny of science. And, unlike abducting aliens, or secret lizard-replicants of world leaders, Sasquatch is a fairly simple, plausible concept. It does not require super spaceship technologies or other stuff that belongs in the realm of science fiction (or fantasy) rather than science. No, the Sasquatch concept simply says that there is a really big primate out in the wilds of the world, a primate of which no specimen, living or dead, has ever been bagged for science. How can a scientist hope to answer that?—especially when the internet is full of “The Truth” about Sasquatch?
Here is one thing a scientist can turn to:
Consider the term “Sasquatch”. When did it appear? Thanks to Google Books, one can search for an unusual term, like “Sasquatch” in a vast number of books published across many centuries. By restricting the range of dates searched across, one can learn something about when the term came into use. I did this with “Sasquatch”. I could not find any solid references to Sasquatch until after the Second World War.
An even simpler way to study this is to use the Google Books Ngram Viewer (click here to try it), which graphs the frequency of occurrence of a word among the books that Google has digitized. Here is what the Ngram Viewer returns for “Sasquatch”:
If Sasquatches really did exist, we might expect that writings from the eighteenth and nineteenth centuries would feature some mention of Sasquatch. After all, that is when there was a rapid expansion of people into the North American wilderness. We might expect people to report encounters with these supposed creatures, just as they reported encounters with bears.
But apparently, while people wrote about the bears they encountered, they did not write about the Sasquatches. Indeed, it rather looks as though Sasquatch is a creation of the 1960’s, in a way that bears are not (the Ngram graphs for “Bigfoot” and “Yeti” are very similar to the one for “Sasquatch”). The rise of Sasquatch as reflected by this graph is surely some sort of indication of a rise in belief—but not belief in science.
There are millions of pieces of rocky material left over from the formation of our solar system. These rocky chunks are called asteroids, and they can be found orbiting our Sun. Most asteroids are found between the orbits of Mars and Jupiter. They orbit the Sun in a doughnut-shaped region of space called the asteroid belt.
The Main Asteroid Belt. Colors: green are main belt asteroids, yellow are asteroids that cross the orbit of Mars, red are asteroids that cross the orbit of Earth. Credit: Scott Manley
Asteroids come in many different sizes—from tiny rocks to giant boulders. Some can even be hundreds of miles across! Asteroids are mostly rocky, but some also have metals inside, such as iron and nickel. Almost all asteroids have irregular shapes. However, very large asteroids can have a rounder shape.
The asteroid belt is about as wide as the distance between Earth and the Sun. It’s a big space, so the objects in the asteroid belt aren’t very close together. That means there is plenty of room for spacecraft to safely pass through the belt. In fact, NASA has already sent several spacecraft through the asteroid belt!
Caption: Enhanced color view of dwarf planet Ceres captured by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The total mass of objects in the asteroid belt is only about 4 percent the mass of our Moon. Half of this mass is from the four largest objects in the belt. These objects are named Ceres, Vesta, Pallas and Hygiea.
The dwarf planet Ceres is the largest object in the asteroid belt. However, Ceres is still pretty small. It is only about 587 miles across—only a quarter the diameter of Earth’s moon. In 2015, NASA's Dawn mission mapped the surface of Ceres. From Dawn, we learned that the outermost layer of Ceres—called the crust—is made up of a mixture of rock and ice.
The Dawn spacecraft also visited the asteroid Vesta. Vesta is the second largest object in the asteroid belt. It is 329 miles across, and it is the brightest asteroid in the sky. Vesta is covered with light and dark patches, and lava once flowed on its surface.
The asteroid belt is filled with objects from the dawn of our solar system. Asteroids represent the building blocks of planets and moons, and studying them helps us learn about the early solar system.
Seventeen years ago, astronomers witnessed a supernova go off 40 million light-years away in the galaxy called NGC 7424, located in the southern constellation Grus, the Crane. Now, in the fading afterglow of that explosion, NASA's Hubble Space Telescope has captured the first image of a surviving companion to a supernova. This picture is the most compelling evidence that some supernovas originate in double-star systems.
“We know that the majority of massive stars are in binary pairs,” said Stuart Ryder from the Australian Astronomical Observatory (AAO) in Sydney, Australia, and lead author of the study. “Many of these binary pairs will interact and transfer gas from one star to the other when their orbits bring them close together.”
Seventeen years ago, astronomers witnessed supernova 2001ig go off 40 million light-years away in the galaxy NGC 7424, in the southern constellation Grus, the Crane. Shortly after, scientists photographed the supernova with the European Southern Observatory’s Very Large Telescope (VLT) in 2002. Two years later, they followed up with the Gemini South Observatory, which hinted at the presence of a surviving binary companion. As the supernova’s glow faded, scientists focused Hubble on that location in 2016. They pinpointed and photographed the surviving companion, which was possible only due to Hubble’s exquisite resolution and ultraviolet sensitivity. Hubble observations of SN 2001ig provide the best evidence yet that some supernovas originate in double-star systems. Credits: NASA, ESA, S. Ryder (Australian Astronomical Observatory), and O. Fox (STScI)
The companion to the supernova’s progenitor star was no innocent bystander to the explosion. It siphoned off almost all of the hydrogen from the doomed star’s stellar envelope, the region that transports energy from the star’s core to its atmosphere. Millions of years before the primary star went supernova, the companion’s thievery created an instability in the primary star, causing it to episodically blow off a cocoon and shells of hydrogen gas before the catastrophe.
Evolution of Type IIb Stripped-Envelope Supernova. Credits: NASA, ESA, and A. Feild (STScI)
The supernova, called SN 2001ig, is categorized as a Type IIb stripped-envelope supernova. This type of supernova is unusual because most, but not all, of the hydrogen is gone prior to the explosion. This type of exploding star was first identified in 1987 by team member Alex Filippenko of the University of California, Berkeley.
How stripped-envelope supernovas lose that outer envelope is not entirely clear. They were originally thought to come from single stars with very fast winds that pushed off the outer envelopes. The problem was that when astronomers started looking for the primary stars from which supernovas were spawned, they couldn’t find them for many stripped-envelope supernovas.
“That was especially bizarre, because astronomers expected that they would be the most massive and the brightest progenitor stars,” explained team member Ori Fox of the Space Telescope Science Institute in Baltimore. “Also, the sheer number of stripped-envelope supernovas is greater than predicted.” That fact led scientists to theorize that many of the primary stars were in lower-mass binary systems, and they set out to prove it.
Looking for a binary companion after a supernova explosion is no easy task. First, it has to be at a relatively close distance to Earth for Hubble to see such a faint star. SN 2001ig and its companion are about at that limit. Within that distance range, not many supernovas go off. Even more importantly, astronomers have to know the exact position through very precise measurements.
VLT's four Unit Telescopes, Credit: ESO/H.H.Heyer
In 2002, shortly after SN 2001ig exploded, scientists pinpointed the precise location of the supernova with the European Southern Observatory’s Very Large Telescope (VLT) in Cerro Paranal, Chile. In 2004, they then followed up with the Gemini South Observatory in Cerro Pachón, Chile. This observation first hinted at the presence of a surviving binary companion.
Knowing the exact coordinates, Ryder and his team were able to focus Hubble on that location 12 years later, as the supernova’s glow faded. With Hubble’s exquisite resolution and ultraviolet capability, they were able to find and photograph the surviving companion—something only Hubble could do.
Prior to the supernova explosion, the orbit of the two stars around each other took about a year.
When the primary star exploded, it had far less impact on the surviving companion than might be thought. Imagine an avocado pit—representing the dense core of the companion star—embedded in a gelatin dessert—representing the star’s gaseous envelope. As a shock wave passes through, the gelatin might temporarily stretch and wobble, but the avocado pit would remain intact.
In 2014, Fox and his team used Hubble to detect the companion of another Type IIb supernova, SN 1993J. However, they captured a spectrum, not an image. The case of SN 2001ig is the first time a surviving companion has been photographed. “We were finally able to catch the stellar thief, confirming our suspicions that one had to be there,” said Filippenko.
Perhaps as many as half of all stripped-envelope supernovas have companions—the other half lose their outer envelopes via stellar winds. Ryder and his team have the ultimate goal of precisely determining how many supernovas with stripped envelopes have companions.
Their next endeavor is to look at completely stripped-envelope supernovas, as opposed to SN 2001ig and SN 1993J, which were only about 90 percent stripped. These completely stripped-envelope supernovas don’t have much shock interaction with gas in the surrounding stellar environment, since their outer envelopes were lost long before the explosion. Without shock interaction, they fade much faster. This means that the team will only have to wait two or three years to look for surviving companions.
The Hubble Space Telescope in orbit. Credit: NASA/JPL-Caltech.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.
The British fantasy writer Neil Gaiman tells the story of attending a gathering of great writers, scholars, and thinkers, and wondering if he really belonged in that group. Next to him, another attendee also named Neil voiced similar doubts. “I just look at all these people, and I think, what the heck am I doing here? They’ve made amazing things. I just went where I was sent.” To which Gaiman replied, “Yes. But you were the first man on the Moon. I think that counts for something.”
The 2017 Annual Report featured the meeting of Nobel laureate Gerald t' Hooft with Pope Francis, introduced by Specola cosmologist Fr. Gabriele Gionti.
In that spirit, in May 2017 I presented to Pope Francis the attendees of our workshop on Black Holes, Gravitational Waves, and Space-time Singularities. The scientists included 35 of the brightest in the field, including a Nobel laureate. Two of them gave the Pope a copy of their work announcing the discovery of gravitational waves. (I gave the Pope a book written by children at my old elementary school.)
A major theme of the workshop was the exchange of information. Would information survive passage into a black hole, or would every kind of ordering be erased in that space-time singularity? The question has implications also for the singularity at the beginning of the Big Bang. What sort of theory would allow one to even answer that question? Will we ever have a workable theory of quantum gravity, to combine the insights of Einstein’s General Relativity (which works fine at astronomical scales) with the quantum physics that seems to operate at the tiniest scales?
What was wonderful to me was seeing how the setting of this workshop at the Vatican provided just the opposite of a black hole: rather than destroying information, the feeling of “neutral ground” here fed discussions that went on long after the formal sessions had ended… into the meals the attendees shared together, the walk through the Papal Gardens, even on the bus ride to the Papal Audience.
Conversation, the transmission of information, is the heart of science. Things can also get mis-transmitted, of course. Most of the news coverage (including in The Tablet) called our meeting a “faith and science” workshop even though the only faith expressed at the meeting was faith in, or against, the standard models of cosmology. (“I really hope there’s a multiverse,” one attendee confessed to me.)
And we got the usual spate of emails and tweets from those who have grand ideas about cosmology, if only the rest of the world would listen. What makes the 35 folks at our workshop worth listening to on this topic more than all the helpful enthusiasts who email us? The experts and prize winners have paid their dues: a lifetime of learning the real meaning of the words “singularity” and “space-time” in a way that journalists (or columnists like me) can only hint at; a lifetime of not only talking, but also listening. (One attendee was notorious for talking over those who disagreed with him; the rest of the group eventually just ignored him.)
That’s one difference between the real scientists and the wanna-be’s. The email writers are sure they are right; we know we aren’t, completely, and never will be. And that’s what gives us courage to believe we’re not imposters. Science is not the truth, but the search for truth.
Pope Francis understands that. “I am deeply appreciative of your work,” he told us, “and I encourage you to persevere in your search for truth. For we ought never to fear truth, nor become trapped in our own preconceived ideas, but welcome new scientific discoveries with an attitude of humility.”
[The title I chose for this column comes from something I once heard my grad school buddy Cliff Stoll say: "Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom."]