The Star of Bethlehem

The MagiFor centuries astronomers have speculated about the famous Star of Bethlehem, which the three Magi (the three wise men/the three kings) followed to the place of Christ’s birth.  Of course, the star may defy scientific explanation altogether, and be viewed as a miracle.  Nevertheless, various astronomical theories have been proposed, including that the star may have been a comet, or a supernova (an exploding star), or a “planetary conjunction” (a gathering of planets in one part of the sky).  In this column, we’ll examine two of today’s most popular theories, both of which hold that the planet Jupiter played a key role.

First, though, it’s useful to recall what the Bible says about the most famous star in history:

After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, “Where is the one who has been born king of the Jews? We saw his star when it rose and have come to worship him.” Continue reading

A Stormy Meteor Shower This Weekend!


Time-lapse photo of a meteor shower. The shooting stars seem to fly out of a particular area of space.

The best display of shooting stars this year occurs over the next few nights, peaking over the night of Saturday and Sunday, December 13 and 14.  This display is called the “Geminid meteor shower”:

  • Shooting stars are meteors — small pieces of dust in space that quickly burn up in Earth’s atmosphere.  The dust particles for the Geminid meteor shower (or “the Geminids” for short) are leftover bits of an asteroid called3200 Phaethon” that flies very near the Sun every 1.4 years.  As the Earth orbits the Sun, every year at about this time we pass through the dust left behind by this asteroid’s many visits to our neck of the galactic woods.
  • It’s called the “Geminids” because the shooting stars in this meteor shower all appear to fly toward us from the Name A Star Live constellation Gemini.  The two brightest stars of Gemini, Castor and Pollux, are referred to as “the Twins” as they were famous brothers in classical mythology.
Shooting Star
A shooting star (in slow motion!). Image Credit: NASA

So if you’re looking for something romantic to do this coming weekend, consider going outside under the night sky with your significant other, and make some wishes upon every shooting star you see!  No telescope or binoculars needed: Just bring along a lawn chair or long towel on which to lie down.  You might want to bring along some food and drink and, depending on where you live in the world, either some mosquito repellant or warm clothing. Then, just look up.  You should see more shooting stars than you normally would on any night of the year.  Under perfect conditions — a clear sky, far from city lights, and viewing during the two or three hours right before sunrise the morning of December 13 — you might see as many as 80 shooting stars per hour.  But you can still see an above average number of shooting stars no matter what time of the night you look.

Hubble Helps Find Smallest Known Galaxy Containing a Supermassive Black Hole


Artist’s View of M60-UCD1 Black Hole, located in the Name A Star Live constellation Virgo
Image Credit: NASA, ESA, STScI-RCC14-41a

Astronomers using data from NASA’s Hubble Space Telescope and ground observation have found an unlikely object in an improbable place — a monster black hole lurking inside one of the tiniest galaxies ever known.

The black hole is five times the mass of the one at the center of our Milky Way galaxy. It is inside one of the densest galaxies known to date — the M60-UCD1 dwarf galaxy that crams 140 million stars within a diameter of about 300 light-years, which is only 1/500th of our galaxy’s diameter.  M60-UCD1 is located in the Name A Star Live constellation Virgo.

If you lived inside this dwarf galaxy, the night sky would dazzle with at least 1 million stars visible to the naked eye. Our nighttime sky as seen from Earth’s surface shows 4,000 stars.

The finding implies there are many other compact galaxies in the universe that contain supermassive black holes. The observation also suggests dwarf galaxies may actually be the stripped remnants of larger galaxies that were torn apart during collisions with other galaxies rather than small islands of stars born in isolation.

“We don’t know of any other way you could make a black hole so big in an object this small,” said University of Utah astronomer Anil Seth, lead author of an international study of the dwarf galaxy published in Thursday’s issue of the journal Nature.

Seth’s team of astronomers used the Hubble Space Telescope and the Gemini North 8-meter optical and infrared telescope on Hawaii’s Mauna Kea to observe M60-UCD1 and measure the black hole’s mass. The sharp Hubble images provide information about the galaxy’s diameter and stellar density. Gemini measures the stellar motions as affected by the black hole’s pull. These data are used to calculate the mass of the black hole.

Black holes are gravitationally collapsed, ultra-compact objects that have a gravitational pull so strong that even light cannot escape. Supermassive black holes — those with the mass of at least one million stars like our sun — are thought to be at the centers of many galaxies.

The black hole at the center of our Milky Way galaxy has the mass of four million suns. As heavy as that is, it is less than 0.01 percent of the Milky Way’s total mass. By comparison, the supermassive black hole at the center of M60-UCD1, which has the mass of 21 million suns, is a stunning 15 percent of the small galaxy’s total mass.

“That is pretty amazing, given that the Milky Way is 500 times larger and more than 1,000 times heavier than the dwarf galaxy M60-UCD1,” Seth said.
One explanation is that M60-UCD1 was once a large galaxy containing 10 billion stars, but then it passed very close to the center of an even larger galaxy, M60, and in that process all the stars and dark matter in the outer part of the galaxy were torn away and became part of M60.

The team believes that M60-UCD1 may eventually be pulled to fully merge with M60, which has its own monster black hole that weighs a whopping 4.5 billion solar masses, or more than 1,000 times bigger than the black hole in our galaxy. When that happens, the black holes in both galaxies also likely will merge. Both galaxies are 50 million light-years away.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

For images and more information about Hubble, visit:


Small Asteroid to Safely Pass Close to Earth Sunday

Asteroid trajectory

This graphic depicts the passage of asteroid 2014 RC past Earth on September 7, 2014. At time of closest approach, the space rock will be about one-tenth the distance from Earth to the moon. Times indicated on the graphic are Universal Time. Image credit: NASA/JPL-Caltech

A small asteroid, designated 2014 RC, will safely pass very close to Earth on Sunday, Sept. 7, 2014. At the time of closest approach, based on current calculations to be about 2:18 p.m. EDT (1:18 p.m. CDT / 18:18 GMT), the asteroid will be roughly over New Zealand. From its reflected brightness, astronomers estimate that the asteroid is about 60 feet (20 meters) in size.

Asteroid 2014 RC was initially discovered on the night of August 31 by the Catalina Sky Survey near Tucson, Arizona, and independently detected the next night by the Pan-STARRS 1 telescope, located on the summit of Haleakala on Maui, Hawaii. Both reported their observations to the Minor Planet Center in Cambridge, Massachusetts. Additional follow-up observations by the Catalina Sky Survey and the University of Hawaii 88-inch (2.2-meter) telescope on Mauna Kea confirmed the orbit of 2014 RC.

At the time of closest approach, 2014 RC will be approximately one-tenth the distance from the center of Earth to the moon, or about 25,000 miles (40,000 kilometers). The asteroid’s apparent magnitude — a measure of how bright an object in the night sky appears to be — at that time will be about 11.5, rendering it unobservable to the unaided eye. However, amateur astronomers with small telescopes might glimpse the fast-moving appearance of this near-Earth asteroid.

The asteroid will pass below Earth and the geosynchronous ring of communications and weather satellites orbiting about 22,000 miles (36,000 kilometers) above our planet’s surface. While this celestial object does not appear to pose any threat to Earth or satellites, its close approach creates a unique opportunity for researchers to observe and learn more about asteroids.

While 2014 RC will not impact Earth, its orbit will bring it back to our planet’s neighborhood in the future. The asteroid’s future motion will be closely monitored, but no future threatening Earth encounters have been identified.

For a heliocentric view of the orbit of asteroid 2014 RC with respect to Earth and other planets, visit:

New Hubble image of a beautiful, spiral galaxy!

PGC 54493

This new NASA/ESA Hubble Space Telescope image shows a beautiful spiral galaxy known as PGC 54493, located in the constellation of Serpens (The Serpent). This galaxy is part of a galaxy cluster that has been studied by astronomers exploring an intriguing phenomenon known as weak gravitational lensing.

This effect, caused by the uneven distribution of matter (including dark matter) throughout the universe, has been explored via surveys such as the Hubble Medium Deep Survey. Dark matter is one of the great mysteries in cosmology. It behaves very differently from ordinary matter as it does not emit or absorb light or other forms of electromagnetic energy — hence the term “dark.”

Even though we cannot observe dark matter directly, we know it exists. One prominent piece of evidence for the existence of this mysterious matter is known as the “galaxy rotation problem.” Galaxies rotate at such speeds and in such a way that ordinary matter alone — the stuff we see — would not be able to hold them together. The amount of mass that is “missing” visibly is dark matter, which is thought to make up some 27 percent of the total contents of the Universe, with dark energy and normal matter making up the rest. PGC 55493 has been studied in connection with an effect known as cosmic shearing. This is a weak gravitational lensing effect that creates tiny distortions in images of distant galaxies.

Credit: European Space Agency, ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

A Beautiful Cluster of Stars!

IC 4499

This new NASA/ESA Hubble Space Telescope image shows the globular cluster IC 4499.

Globular clusters are big balls of old stars that orbit around their host galaxy. It has long been believed that all the stars within a globular cluster form at the about same time, a property which can be used to determine the cluster’s age. For more massive globulars however, detailed observations have shown that this is not entirely true — there is evidence that they instead consist of multiple populations of stars born at different times. One of the driving forces behind this behavior is thought to be gravity: more massive globulars manage to grab more gas and dust, which can then be transformed into new stars.

IC 4499 is a somewhat special case. Its mass lies somewhere between low-mass globulars, which show a single generation build-up, and the more complex and massive globulars which can contain more than one generation of stars. By studying objects like IC 4499 astronomers can therefore explore how mass affects a cluster’s contents. Astronomers found no sign of multiple generations of stars in IC 4499 — supporting the idea that less massive clusters in general only consist of a single stellar generation.

Hubble observations of IC 4499 have also helped to pinpoint the cluster’s age: observations of this cluster from the 1990s suggested a puzzlingly young age when compared to other globular clusters within the Milky Way. However, since those first estimates new Hubble data been obtained, and it has been found to be much more likely that IC 4499 is actually roughly the same age as other Milky Way clusters at approximately 12 billion years old.

Credit: ESA/Hubble & NASA

Beautiful Space Imagery

Here are some beautiful space photos and videos that have been posted on the Internet recently. Enjoy!

Entitled “New England Nights,” this is an absolutely wonderful compilation of panoramas, timelapses, and still photos of the night sky in Maine and New Hampshire.

Apollo 11 astronaut

Apollo 11 astronaut Buzz Aldrin on the lunar surface

In tribute to the annual celebration of the Apollo 11 lunar landing, July 20, 1969, we’re posting this famous photo of Astronaut Buzz Aldrin.

Stunning Night Sky Images: Earth & Sky Photo Contest 2014!

NASA video of astronauts on the International Space Station getting in the World Cup spirit!

Kittens in Space!

Hubble Eyes Golden Rings of Star Formation

NGC 3081

Taking center stage in this new NASA/ESA Hubble Space Telescope image is a beautiful galaxy known as NGC 3081, set against an assortment of glittering galaxies in the distance. Located in the constellation of Hydra (The Sea Serpent), NGC 3081 is located over 86 million light-years from us. It is known as a type II Seyfert galaxy, characterized by its dazzling nucleus.

NGC 3081 is seen here nearly face-on. Compared to other spiral galaxies, it looks a little different. The galaxy’s barred spiral center is surrounded by a bright loop known as a resonance ring. This ring is full of bright clusters and bursts of new star formation, and frames the supermassive black hole thought to be lurking within NGC 3081 — which glows brightly as it hungrily gobbles up in-falling material.

These rings form in particular locations known as resonances, where gravitational effects throughout a galaxy cause gas to pile up and accumulate in certain positions. These can be caused by the presence of a “bar” within the galaxy, as with NGC 3081, or by interactions with other nearby objects. It is not unusual for rings like this to be seen in barred galaxies, as the bars are very effective at gathering gas into these resonance regions, causing pile-ups which lead to active and very well-organized star formation.

Hubble snapped this magnificent face-on image of the galaxy using the Wide Field Planetary Camera 2. This image is made up of a combination of ultraviolet, optical, and infrared observations, allowing distinctive features of the galaxy to be observed across a wide range of wavelengths.

Image credit: ESA/Hubble & NASA; acknowledgement: R. Buta (University of Alabama)
  Text credit: European Space Agency

Hubble Space Telescope’s New, Beautiful Deep Space Image!

Hubble Ultra Deep Field image

This is a composite image showing the visible and near infrared light spectrum collected from Hubble’s ACS and WFC3 instruments over a nine-year period. Image Credit: NASA/ESA

Astronomers using NASA’s Hubble Space Telescope have assembled a comprehensive picture of the evolving universe – among the most colorful deep space images ever captured by the 24-year-old telescope.

Researchers say the image, in new study called the Ultraviolet Coverage of the Hubble Ultra Deep Field, provides the missing link in star formation. The Hubble Ultra Deep Field 2014 image is a composite of separate exposures taken in 2003 to 2012 with Hubble’s Advanced Camera for Surveys and Wide Field Camera 3.

Astronomers previously studied the Hubble Ultra Deep Field (HUDF) in visible and near-infrared light in a series of images captured from 2003 to 2009. The HUDF shows a small section of space in the southern-hemisphere constellation Fornax. Now, using ultraviolet light, astronomers have combined the full range of colors available to Hubble, stretching all the way from ultraviolet to near-infrared light. The resulting image — made from 841 orbits of telescope viewing time — contains approximately 10,000 galaxies, extending back in time to within a few hundred million years of the big bang.

Prior to the Ultraviolet Coverage of the Hubble Ultra Deep Field study of the universe, astronomers were in a curious position. Missions such as NASA’s Galaxy Evolution Explorer (GALEX) observatory, which operated from 2003 to 2013, provided significant knowledge of star formation in nearby galaxies. Using Hubble’s near-infrared capability, researchers also studied star birth in the most distant galaxies, which appear to us in their most primitive stages due to the significant amount of time required for the light of distant stars to travel into a visible range. But for the period in between, when most of the stars in the universe were born — a distance extending from about 5 to 10 billion light-years — they did not have enough data.

“The lack of information from ultraviolet light made studying galaxies in the HUDF like trying to understand the history of families without knowing about the grade-school children,” said principal investigator Harry Teplitz of Caltech in Pasadena, California. “The addition of the ultraviolet fills in this missing range.”

Ultraviolet light comes from the hottest, largest and youngest stars. By observing at these wavelengths, researchers get a direct look at which galaxies are forming stars and where the stars are forming within those galaxies.

Studying the ultraviolet images of galaxies in this intermediate time period enables astronomers to understand how galaxies grew in size by forming small collections of very hot stars. Because Earth’s atmosphere filters most ultraviolet light, this work can only be accomplished with a space-based telescope.

“Ultraviolet surveys like this one using the unique capability of Hubble are incredibly important in planning for NASA’s James Webb Space Telescope,” said team member Dr. Rogier Windhorst of Arizona State University in Tempe. “Hubble provides an invaluable ultraviolet light dataset that researchers will need to combine with infrared data from Webb. This is the first really deep ultraviolet image to show the power of that combination.”

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

For Hubble Ultra Deep Field 2014 images and more information about Hubble, visit: and