NASA Has Reestablished Contact with the STEREO-B Spacecraft

On August 21, 2016, communications was reestablished with STEREO-B spacecraft - one of NASA's Solar Terrestrial Relations Observatories. Communications with the spacecraft were lost on October. 1, 2014; using NASA's Deep Space Network, the STEREO team attempted monthly recovery operations to try to regain contact with the spacecraft, and their efforts have paid off!

The Deep Space Network (DSN) locked onto the STEREO-B downlink carrier at 6:27 p.m. EDT. The signal was monitored by the Mission Operations team for several hours, then the spacecraft's transmitter was switched off to conserve battery power. The STEREO team will perform further recovery operations to assess the health of the observatory's subsystems and instruments, and to re-establish attitude control.

Communications with the STEREO-B spacecraft were lost during a test of the spacecraft’s command loss timer - a hard reset that is triggered 72 hours after the spacecraft has gone without communications from Earth. This function was being tested by the STEREO team in preparation for a solar conjunction; during a conjunction, the STEREO spacecraft's line of sight to Earth is blocked by the Sun, and communications are not possible.

The STEREO-A spacecraft continues to work normally.

Position of STEREO Spacecraft on August 23, 2016. Credit: NASA Eyes on the Solar System / Bob Trembley

Position of the STEREO spacecraft on August 23, 2016. Credit: NASA Eyes on the Solar System / Bob Trembley

Near-Live rotating GIF of the sun as seen by STEREO. Credit: NASA/JPL-Caltech.

From the STEREO website:

"STEREO (Solar TErrestrial RElations Observatory) is the third mission in NASA's Solar Terrestrial Probes program (STP). The mission, launched in October 2006, has provided a unique and revolutionary view of the Sun-Earth System. The two nearly identical observatories - one ahead of Earth in its orbit, the other trailing behind - have traced the flow of energy and matter from the Sun to Earth. STEREO has revealed the 3D structure of coronal mass ejections; violent eruptions of matter from the sun that can disrupt satellites and power grids, and help us understand why they happen. STEREO is a key addition to the fleet of space weather detection satellites by providing more accurate alerts for the arrival time of Earth-directed solar ejections with its unique side-viewing perspective."

For more on STEREO:

UFOs and Roswell, New Mexico

Do you believe in unidentified flying objects (UFOs)? When asked that question I usually respond, "What does that mean?" If it means do I think aliens from another planet have landed on Earth then the answer is no. We have never found any evidence of life complex or simple, anywhere outside of our own planet.

If it means do aliens exist somewhere in the universe then the answer is unknown. It would be excellent to know one day, yet at the moment the answer is completely unknown. So what about famous claims about UFOs, with one such example being the supposed crash of a UFO near Roswell, New Mexico in 1949?

Following the release of classified records released in 1995 we now know the full story. It all started when the United States government initiated an experiment called Project Mogul in the mid- to late-1940s to monitor any Russian nuclear tests taking place at the time. Detectors were constructed consisting of many fat round-shaped microphones called disk microphones. The disk microphones were so sensitive that they could detect sound vibrations from distant sources such as those produced in distant mushroom clouds.

Operationally, many disk microphones were tethered together using strings and then flown as one large system of sound detectors at high altitudes across the desert. Project Mogul did manage to detect a real Russian nuclear test in 1949 and measure its strength. The interesting part is that wwo years prior to this experimental run, there was an unsuccessful run in which the entire disk microphone system crashed in the desert near to a town called Roswell, New Mexico.

Residents noticed hardware falling out of the sky. When prompted for what had happened, a spokesperson for Project Mogul accidentally divulged that "flying disks" (the nickname for the disk microphones) had crashed. This press release, which revealed top secret information, was quickly corrected to read that a weather balloon had crashed.

The new explanation did not fly (excuse the pun!) as residents of Roswell had already recovered parts that did not resemble a balloon. Further, the unfortunate choice of nickname of flying disks sounds an awful lot like "flying saucers." At that point the spokesperson, who had already said too much, was forced to remain silent. Thanks to healthy and unchecked human imagination, the story went 'viral,' and a fairy tale was born.

Astronomy, Ecology, and Social Ethics: Looking at Climate Trends for 2016

2016 has been a record setting year in regard to climate change. NASA has confirmed that the temperatures from January to June have set new, all-time highs. An article on NASA's website from July 19, 2016 states that temperatures are 1.3 degrees Celsius warmer than recent historical averages. Sea ice levels in the first five months receded to new lows since we began to measure it with satellites in 1979. Though some may question the reality of global warming, science is confirming that our world's climate is changing and rapidly.

For the full article on recent NASA findings about our climate, click here.

Thankfully, the record ice melt in the first five months of this year has slowed through the month of June. This slowing will keep the arctic ice from setting even more record lows. Nevertheless, NASA has stated that these findings are pointing to a "new normal" for our climate and are seeking to answer the question, "What does this mean going forward?"

Image of Robins being being outfitted with GPS as part of ABoVE's research. Click on the image to learn more about ABoVE.

ABoVE researchers fitting a Robin with a GPS tracking device. Credits: Boelman/Lamont-Doherty Earth Observatory

With dramatic changes in temperatures and ice levels, the scientific community fears that this will impact arctic ecosystems. Studies have begun to track migration patterns of birds in Northern Alaska through a project called ABoVE. The research is in the early stages, but preliminary data shows a change in bird migration patters. In particular, the study has found that robins are starting to migrate further north to northern Alaska to breed. Time will tell how or if these and other new migration patterns will impact other parts of the ecosystem.

Another new advancement in studying the arctic climate has been developed for Greenland. NASA has constructed the first ever map of the regions under Greenland's ice sheets. Since this map is new, time and study will refine this map and expand what we can learn about Greenland's massive sheets of ice. The team lead, Joe MacGregor, calls this map a "piñata" since the scientific community will most likely find its many faults. However, MacGregor invites this criticism, arguing that finding the map's faults will only improve our understanding of the environment.

The first ever map of Greenland's underground ice. Credits: NASA Earth Observatory/Jesse Allen

The first ever map of Greenland's underground ice. Credits: NASA Earth Observatory/Jesse Allen

As a parish priest, I am blessed to live and work with the people of God whom I serve. Just as our country reflects many different attitudes about climate change, so, too, do the people I serve. One of the reasons I think there is such confusion about climate change is that climate science is relatively new.  For example, the map of Greenland's underground ice sheets will help us understand climate change in the future. However, it doesn't tell us much of the past since this is a first of its kind research tool. This is a good example of why there are so many opinions about the current state of global climate change. Understanding our climate needs time and patience to reveal the deeper scientific truths about our common home. In a culture that struggles with patience, climate change can become fertile soil for divergent opinions.

Amid this sea of divergent opinions, a reasonable question to ask is whether or not there is anything we can do to improve our environment? Those whose passion is protecting our common home find this question deflating and aggravating. However, when much of climate science is about what might happen in the future, this room for interpretation allows an apathetic mentality to justify a lack of response as a legitimate response. Our Catholic faith, however, resists this interpretation. Pope Francis argues in Laudato Si' that doing nothing risks far to much. Further, Catholic Social Teaching reminds us that we are to have a forward looking solidarity. This means that we have a responsibility to care for our common home so that future generations can have access to natural resources the way we do today.

This forward looking solidarity is central to Catholicism's vision of environmental ethics. Despite clear, Biblical references to caring for God's creation, there is much confusion about how Catholics are to approach ecology. Just as many of the tools used for climate science are new, so is theological reflection on modern ecological questions. Nevertheless, the same principles that guided the Church to view creation as fundamentally good despite the fall also calls us to care for God's creation to continue the protection and promotion of human dignity at all stages of life. This call to human dignity reminds us that a Catholic vision of ecology is rooted in morality and ethics. Pope Francis reminds us of this in Laudato Si', calling us to ask what we can do to protect our common home.

“The external deserts in the world are growing, because the internal deserts have become so vast”. For this reason, the ecological crisis is also a summons to profound interior conversion. It must be said that some committed and prayerful Christians, with the excuse of realism and pragmatism, tend to ridicule expressions of concern for the environment. Others are passive; they choose not to change their habits and thus become inconsistent. So what they all need is an “ecological conversion”, whereby the effects of their encounter with Jesus Christ become evident in their relationship with the world around them. Living our vocation to be protectors of God’s handiwork is essential to a life of virtue; it is not an optional or a secondary aspect of our Christian experience. (Laudato Si'. 217)

Spiritual exercise: What is our understanding of the ethical and moral dimensions of ecology? Are we willing to make small changes that may help impact human dignity for years to come? Do we gravitate toward an attitude of indifference due to the unknowns about our climate's future? Pray with these questions today and, together, may we embrace God's call to care for our common home so that humanity may always be able to provide the most basic needs to build up human dignity.

Also in Integral Ecology

  1. Human Ecology: What Is It?
  2. Laudato Si’ – Encyclical on Ecology: Post #1: Let’s All Take a Deep Breath
  3. Laudato Si’ – Post #2: Introduction and Chapter One: A Plea for Action.
  4. Laudato Si’ – Post #3: Chapter Two – Pope Francis and the Last March of the Ents
  5. Laudato Si’ – Post #4: Chapters Three and Four – Unmasking Radical Anthropocentrism.
  6. Laudato Si’ – Post #5: Chapter 5 – Politics, Religion, and Science at the Dinner Table? Yes, When Dinning With Pope Francis!
  7. Laudato Si’: Final Post – Chapter Six: Broadening Our Language of Reverence.
  8. What Happens if the Earth Dies? Astronomy, Ecology, and Social Change.
  9. What Can the Sun Do to Us? Solar Flares, Technology, and Pope Francis.
  10. Amid Creation’s Groaning, There is Hope: Exploring The Intimate Connection Between God And Creation During Advent.
  11. COP21: Understanding the Paris Climate Change Conference in Light of Laudato Si’.
  12. Seeing is Believing: The Role Astronomy Plays in Understanding Global Climate Change.
  13. When the Heavens and Earth Were Sacred: Recapturing a Sacramental Worldview.
  14. Give Drink To The Thirsty: Ecology, Astronomy, And The Year of Mercy
  15. Reading Creation: Exploring The Book of Nature and The Book of Scripture (Part One)
  16. Reading Creation: Exploring The Book of Nature and The Book of Scripture (Part Two)
  17. Priests of Creation: Reclaiming Biblical Ecology through Maximus the Confessor
  18. Astronomy, Ecology, and Social Ethics: Looking at Climate Trends for 2016

View the entire series

From the Cabinet of Physics: Dressed for the Electrostatic Dance

Here is a display of electrical forces that is more whimsical than profound. It may not add very much to our knowledge of physics. But I am fond of it.

A revolving Wimshurst machine, connected to two horizontal metal plates, produces an ever-changing charge on the plates, and thus a changing electric field in the space between them.

Between the plates are placed two lightweight figures made of pith, a cork-like substance. These mannequins are tiny, but they are elegantly dressed in fine 19th-century style.

When the machine is cranked, the puppets respond to the changing electric field between the plates by dancing. They hop up and down, alternately attracted and repelled by the nearby plates.

Any other small, light insulating objects would have served to illustrate this effect. But I think it's charming to watch characters dressed for a ball do the dancing.

Wimshurst machines have many uses, and have played a supporting role in several Cabinet videos we have previously featured. I imagine that typically, in a classroom lecture, this simple demonstration would be one of several electrostatic experiments the lecturer would show.

The Foundation for Science and Technics, or Fondazione Scienza e Tecnica, of Florence, Italy, has made available many videos exploring the Cabinet of Physics, a large collection of antique scientific demonstration instruments.  The Foundation's homepage may be found here, and its Youtube channel, florencefst, here.

Across the Universe: Clouds from Both Sides

This column first ran in The Tablet in August 2010

Saturday, seventeen hours from California, my friend Dan and I land in Australia. We’re looking forward to a week of observing southern stars, researching our latest book, a guide for amateur astronomers.

Not an astronomer's dream... clouds of Australia

Not an astronomer's dream... clouds of Australia

Brother Ian meets us at the airport and leads us to the Jesuit winery and retreat house at Sevenhill, two hours north of Adelaide. Even jet-lag and a partly cloudy sky can’t stop us from pulling out our telescopes that night and peeking at Rigel Kentaurus, our Sun’s nearest neighbor, and Acrux, the brightest star of the Southern Cross. Both are double stars, first split by Jesuit missionaries in the 17th century.  After half an hour, the sky clouds over completely. But not to worry, we have the whole week before us.

(A heat wave across North America threatens the lives of the poor and elderly.)

Sunday, Ian shows us around the vineyards and the tells us the history of the 19th century Jesuit mission. We see photos of the Austrian Jesuits who came with dreams of a seminary and university that never materialized (soon after they arrived, most of the locals left for the gold fields further east); photos of the stern bishop under whom they worked; and the place where [then] soon-to-be-canonized Mother Mary MacKillop stayed when she came through, about the time that said bishop excommunicated her. Cloudy. We watch a DVD of Little Miss Sunshine.

Monday we go shopping for chocolate and Coca Cola in the little village of Clare. Sunset reveals a brilliant clear sky, and out come the telescopes. I get to see the glorious nebula around Eta Carina slowly fade from sight as the clouds roll back in. However, the forecast promises clearing on Wednesday.

(Massive floods hit Pakistan.)

Tuesday, Ian gives us a tour of the surrounding countryside. Amid odd trees and strange birds we look across the Clare valley and south over the rich agricultural region towards Adelaide. A signpost at one of the lookouts has an arrow indicating “New York, 19,000 km”. Dan, a New Yorker, sighs. “You could go in the opposite direction for 21,000 km,” I helpfully point out. Cloudy night. The forecast now: clear skies will arrive on Thursday, then storms on Saturday.

Wednesday is pouring rain. I start reading a thick and dreadful fantasy novel I bought in Clare. Dan and I take turns getting up during the night, hoping for a clearing that never comes.

Thursday. Cloudy. See four kangaroos. We stay up hoping for a break in the clouds, and watch the directors’ commentary track of Little Miss Sunshine. We give up at 4:30 am. Three days left. How could God be so cruel as to let me come all this way, just to be frustrated? Why does He hate me?

(Bad weather in China leads to devastating landslides.)

Friday morning, the blue skies so long forecast are finally here. Local farmers tell us the clouds lifted at 5 am. It stays sunny, until evening. The internet cloud-cover map says that Sevenhill is perfectly clear; our eyes say, perfectly awful. Around 10 pm, we spot stars through a hole in the muck. It lasts just long enough for me to find and split a faint double star in Centaurus before the inevitable clouds return.

Saturday, the weatherman is finally vindicated: as predicted, it storms. That evening the 150 year old church, hand crafted by Jesuit brothers and still not finished, is filled with the local farmers and their families. In the pew behind us is a family of twelve, including four pairs of twins. Among the parish announcements at the end of Mass, Father Pippin comments: “We’ve been blessed this past week with the rain we so desperately need. You can thank the two American astronomers among us...”

The cloud-covered church of Sevenhill

The cloud-covered church of Sevenhill

[We eventually got back to Australia in December and had one good night of observing, enough to complete the Southern sections for our book, Turn Left at Orion. And in the end of August 2016 I'll be returning to Sevenhill for my annual retreat. There's a telescope at the retreat house we left behind after our last visit...]

Also in Across the Universe

  1. Across the Universe: What’s in a Name?
  2. Across the Universe: Fools from the East
  3. Across the Universe: Hunches
  4. Across the Universe: Desert or a dessert?
  5. Across the Universe: Stardust messages
  6. Across the Universe: The best way to travel
  7. Across the Universe: Original Proof
  8. Across the Universe: Pearls among Swine
  9. Across the Universe: One Fix Leads to Another
  10. Across the Universe: Limits to Understanding
  11. Across the Universe: Words, Words, Worlds: Have We Found Planet X?
  12. Across the Universe: The Glory of a Giant
  13. Across the Universe: Fire and Ice
  14. Across the Universe: Science as Story
  15. Across the Universe: Recognition
  16. Across the Universe: Tending Towards Paganism
  17. Across the Universe: The Ethics of Extraterrestrials
  18. Across the Universe: Orbiting a New Sun
  19. Across the Universe: Seeing the Light
  20. Across the Universe: DIY Religion
  21. Across the Universe: Truth, Beauty, and a Good Lawyer
  22. Across the Universe: Techie Dreams
  23. Across the Universe: By Paper, to the Stars
  24. Across the Universe: Transit of Venus
  25. Across the Universe: Ordinary Time
  26. Across the Universe: Deep Impact
  27. Across the Universe: New Worlds
  28. Across the Universe: Tom Swift and his Helium Pycnometer
  29. Across the Universe: Tradition… and Pluto
  30. Across the Universe: Bucks or Buck Rogers?
  31. Across the Universe: Key to the Sea and Sky
  32. Across the Universe: Off The Beach
  33. Across the Universe: All of the Above
  34. From the Tablet: Tales of Earthlings
  35. Across the Universe: Heavenly peace?
  36. Across the Universe: Help My Unbelief
  37. Across the Universe: Stories of Another World
  38. Across the Universe: Planetary Counsels
  39. Across the Universe: Words that Change Reality
  40. Across the Universe: New Heavens, New Earth
  41. Across the Universe: Souvenirs from Space
  42. Across the Universe: For the love of the stars…
  43. Across the Universe: Spicy planet stories
  44. Across the Universe: Asking the right questions
  45. Across the Universe: Everything You Know Is Wrong
  46. Across the Universe: Errata
  47. Across the Universe: Clouds of Unknowing
  48. Across the Universe: Being Asked the Right Questions
  49. Across the Universe: Recognizing the Star
  50. Across the Universe: Heavenly Visitors
  51. Across the Universe: Christmas Presence
  52. Across the Universe: When Reason Itself Becomes Flesh
  53. Across the Universe: Spinning our Hopes
  54. Across the Universe: Relish the Red Planet
  55. Across the Universe: Obedience
  56. Across the Universe: Traveling Light
  57. Across the Universe: The Still Voice in the Chaos
  58. Across the Universe: Europa
  59. Across the Universe: Defamiliarization
  60. Across the Universe: Forbidden Transitions
  61. Across the Universe: Genre and Truth
  62. Across the Universe: False Economies
  63. Across the Universe: Reflections on a Mirror
  64. Across the Universe: Japan
  65. From the Tablet: Why is Easter So Early This Year?
  66. Across the Universe: Oops!
  67. Across the Universe: Dramatic Science
  68. Across the Universe: Me and My Shadows
  69. Across the Universe: Touch the Sky
  70. Across the Universe: Treasure from Heaven
  71. Across the Universe: Gift of Tongues
  72. Across the Universe: Maverick Genius
  73. Across the Universe: Awareness
  74. Across the Universe: Friends in high places
  75. Across the Universe: A Moving Experience
  76. Across the Universe: Grain of truth
  77. Across the Universe: Clerical Work
  78. Across the Universe: Teaching new stars
  79. Across the Universe: Science for the Masses
  80. Across the Universe: Changelings
  81. Across the Universe: Three Lunatic Answers
  82. Across the Universe: Dawn of My Belief
  83. Across the Universe: Martian Sunrise
  84. Across the Universe: Under the Southern Cross
  85. Across the Universe: Clouds from Both Sides

View the entire series

Summer Stars (iv)

This is the last in a series of four posts on the stars of the summer night sky: bright stars like Vega and Arcturus; middling stars like Polaris (the North Star) and Mizar (the star in the “bend” of the Big Dipper’s handle); and faint stars like Rho Leo and the companion of Mizar, Alcor.  These posts have asked what it is we see when we look at the summer stars.  They have questioned the idea that the sun is a star, and have asked if the stars are suns.  And they have asked how we even know anything about the stars at all.


We have learned how we know what the stars are, and using that knowledge we have seen that while the sun is certainly a star, the summer stars themselves vary wildly in size and in power or luminosity.  Among such incredible stellar diversity are many bodies that are very different from the sun.  But all this knowledge about the stars came from just three measurements:

  • An annual motion of a star (parallax).
  • The magnitude of that star.
  • The color of that star.

We do not measure the size of a star like we might measure the size of a window with a ruler.  We do not measure the distance to a star like we might measure the distance to a friend’s house with our car’s odometer.  We do not measure the power output of a star like an engineer might measure the output of a new kind of light bulb.  We have never been to a star to make such direct measurements, and we are not likely to go to one in the near future.  Rather, we measure movement, magnitude, and color, and from these things we reason mathematically to determine the star’s size, distance, temperature, and luminosity.  HotIronWe reason by analogy—the light of stars matches the light given off by a dense, incandescent object like a piece of hot iron.  We suppose that stars and incandescent iron behave in the same basic ways: the luminosity of an iron ball increases as the square of its radius and the fourth power of its temperature, thus so does the luminosity of a star.  In short, we suppose that the heavens and the Earth are under the same rule.

If we are wrong about the specific supposition that stars and glowing iron have something in common, we may be very wrong about the sizes and luminosities of stars now, but we can hope to figure things out better in the future.  And we can imagine why there might be limits to this sort of supposition.  For example, my fellow blogger Brenda Frye has noted that there is a limit to how massive a star can be, and that limit is only about 150 times the mass of the sun.  But Antares takes up much, much more than 150 times the volume of the sun.  Antares must be a lot less dense than the sun.  How much less dense can Antares be before it stops being a “dense, incandescent body,” and the analogy to iron breaks down, throwing off our mathematical reasoning?  On the other hand, if we are wrong about the general supposition that the heavens and the Earth are under the same rule, so that in fact maybe the stars are controlled by magic Elves who choose the coloring and brightness and motion of the stars for their own inscrutable Elvish reasons, that would do more than throw off our reasoning a bit.  That would mean that we could never hope to know anything about the stars other than their motion, their magnitude, and their color.  That would really stink.

Keep this in mind when you look up at the summer stars, or when you hear about how far away a certain star is, or how large or powerful it might be.  It is cool, cool, cool to be able to look up at the summer sky and see the stars, and know something about what you are looking at, and to know how you know what you know, and to know why it is even possible to know what you know.  There is so much to see and think about in the stars of the summer sky.

Astronomy Picture of the Day

M100, a Spiral Galaxy - posted on the APOD in June 1995. Credit: NASA, Hubble Space Telescope

M100, a Spiral Galaxy - posted on the APOD on June 26, 1995. Credit: NASA, Hubble Space Telescope

Dr. Robert J. Nemiroff is co-creator of the award-winning Astronomy Picture of the Day (APOD) website. While visiting with friends in Michigan's scenic Keweenaw Peninsula, I stopped by the Michigan Tech campus, and spoke with Dr. Nemiroff in his office. Waves of nostalgia washed over me as I arrived at Physics Department in the early afternoon, Dr. Nemiroff was working on the 2017 APOD calendar as I was escorted into his office.

The APOD website debuted on June 16, 1995, when the Internet was a shiny new thing, and just starting to spread throughout and businesses and homes. The APOD predates Google - the earliest posts were made before the introduction of the HTML <center> tag. At that time, Dr. Nemiroff was rooming with Jerry Bonnell at NASA Goddard; they wanted a way to show the public the awesome imagery coming from earth-bound observatories, space telescopes, robotic probes, and the like. They asked NASA if they could do that via a website. NASA pretty much said: "We WANT the public to see this stuff." After finding out the requirements for image copyright and use, they started posting, stopping only briefly during the 2013 sequestration - even then, the APOD mirror sites continued unabated.

When I asked Dr. Nemiroff if he'd had any astronomy courses in school, he said that he had one session in junior-high/high school, and maybe one in elementary - which is typical of the response I get from nearly everyone I ask.

I asked him "How did you get into astronomy?" He told me he'd been interested since second grade; he remembers being able to recite the names of the planets faster than any of his classmates; I smiled, waved my left hand above my head, and pointed to myself. In grad school he had an 8 inch refractor telescope. I'm only a few months older than Dr. Nemiroff, so our childhoods were right in the middle of the Space Race, and I know the effect that had on me!

Dr. Nemiroff was surprised, with all the changes in technology, and the evolution of the Internet, that the APOD has not only remained, but has grown - spawning mirror sites, being translated into nearly two dozen languages, and never running out of interesting material to post. With the recent explosive growth of "Big Data" in astronomy, I doubt the APOD will ever run out!

Pillars of Star Creation

M16: The iconic Pillars of Star Creation. Credit: J. Hester, P. Scowen (ASU), HST, NASA

In 2015, Dr. Nemiroff and Dr. Bonnell were awarded the The Klumpke-Roberts Award for outstanding contributions to public understanding and appreciation of astronomy for their work on the Astronomy Picture of the Day.

On the way out, I stopped to browse his bookshelf filled with astronomy books and course textbooks (I may have drooled a little...)
"You want one?" He asked.
"What‽" I blurted.
"I get sent astronomy course textbooks all the time..." he said, rummaging around in a stack of material next the bookshelf. "Yea, here!" He said, handing me a large-format softcover course textbook, still in the see-thru mailer.
Far be it from me to refuse the offer of a free college-level astronomy textbook!

The Astronomy Picture of the Day is simply a fantastic website, and a great way for science teachers to start their student's day!

Dr. Nemiroff has a free online Astronomy 101 video lecture series:

New Rumors of a Potential Earth-like Exoplanet Could Get Major Attention… If It’s True.

Is there an Earth-like exoplanet in our galactic backyard? For those who stay on top of space news, you may have run across this rumor. The websites Universe Today, Discover Magazine, and are running a tantalizing speculation that the European Southern Observatory (ESO) will be announcing the discovery of a new, Earth-like exoplanet later this month. All three articles state that the planet to be announced is orbiting the star Proxima Centauri, which is a little over four light years away. The piece from Universe Today even speculates of a nanocraft that could reach this star within our lifetime. Needless to say, this has the potential of being some rather exciting news! Having written for The Catholic Astronomer now for over a year, I have learned to be quite cautious about these type of rumors. One of the reasons is that anyone can go online and find an amazing amount of astronomy rumors and speculations on any given day – most of … Continue reading

The Humble Stuff between the Galaxies

We normally study galaxies by looking directly at them. We admire the brilliant arms in spiral galaxies like the Milky Way, the giant football-shaped elliptical galaxies, or even the powerful jets emanating from galaxies with supermassive black holes at their centers, the so-called Active Galactic Nuclei (AGN). As dramatic as such images are, much can be gained also by looking at the impact of these spectacular light-producing objects on the material that sits between the galaxies. We know that hydrogen exists in large amounts in stars and in the galaxies that house the stars. Hydrogen also is the main material found in between the galaxies. Hydrogen, which is made up of one proton and one electron, has a property that it is opaque to UV radiation. A UV photon of light incident on a hydrogen atom will be absorbed. An effect of this absorption is that the electron will be freed or ‘ionized.’ This ionization leaves a signature in the … Continue reading

From the Cabinet of Physics: Yanking on the Hemispheres of Magdeburg

Here’s a classic experiment involving air pressure, one of the earliest demonstrations placed online by “Florencefst,” the Fondazione Scienza e Tecnica’s collection of scientific YouTube videos. The introduction is Italian; in English, it says “Hemispheres of Magdeburg,” and indicates that this demonstration apparatus dates from the first half of the nineteenth century. The top and bottom brass hemispheres are placed together. Next the bottom hemisphere, which incorporates a valve, is connected through a hose to a vacuum pump (which is not visible) and a mercury-filled pressure gauge (the glass device on the right). As the pump is operated, we see the level of mercury change, indicating that the pump is removing most of the air from within the hemispheres. The valve attached to the bottom hemisphere is closed. Now the vessel contains a vacuum.  Well, it would be more precise to say that the air pressure within the hemispheres is much lower than the air pressure in the room outside, … Continue reading

Across the Universe: Under the Southern Cross

This column first ran in The Tablet in August, 2009 Galaxies whirled before us, their curled spiral arms lit up like Christmas trees with bright infrared dots where young stars were being formed from interstellar clouds of gas and dust. Meanwhile, in their central bulges, streams of similar gas and dust were feeding the maws of  supermassive black holes, emitting high energy radiation in their death plunges. Looking at galaxies ever farther away in space, we could trace out ever further back in time the evolution of galactic clusters from filaments of matter shaped by energies we didn’t even know existed ten years ago, which we must merely label as “dark”. We saw the swirling convection of a collapsing stellar core as modeled by a computer that almost, but not quite, reproduced the explosion of a supernova bursting as bright as any one of those galaxies. Not quite reproduced; because our models aren’t quite right yet. We have not yet discovered, … Continue reading

Summer Stars (iii)

The summer night sky is full of stars—bright stars like Vega and Arcturus, middling stars like Polaris (the North Star) and Mizar (the star in the “bend” of the Big Dipper’s handle), and dim stars like Rho Leo (a faint star in the constellation of Leo, the lion) and Alcor (the faint companion of Mizar).  When we look at these stars, what are we seeing?  Astronomers say that the sun is a star.  Are the stars then suns?  How do we even know what these stars are?  In the posts from two weeks ago and from last week we laid the groundwork for answering these questions.  We looked at the stellar magnitude system and the things that affect a star’s magnitude.  Now let’s finally answer the questions. Let’s begin with Vega.  Vega is magnitude 0.0—one step brighter on the magnitude scale than the summer star Spica, which is magnitude 1.0.  Vega’s parallax is 0.130 arc seconds.  Reading off the parallax … Continue reading