Astronomy

What are the most popular galaxies for which we have images?

What are the most popular galaxies for which we have images?


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The only galaxies I can think of (not being an astronomer) are Andromeda and Milky Way. There are 51 near galaxies, but they all pretty much say "satellite of Milky way" or "satellite of Andromeda". There are 100k+ galaxies in the local supercluster, and that page seems to have a better list:

  • Corvus
  • Coma Berenices
  • Ursa Major
  • Virgo
  • Sculptor
  • etc.

If you had to rank them in order of prominence in the scientific community or in popular science, wondering what the top 10 or 20 galaxies would be (for which we have photos).

I am trying to come up with a list of images for educational purposes that are potentially somewhat familiar to laymen audiences, or which would be useful to introduce to laymen audiences.


Any such list is going to be terribly subjective. Since I'm an astronomer who studies galaxies, I'll go ahead and throw out a subjective list of the more famous, photogenic, and/or scientifically well-studied galaxies. The first six are in the Local Group (LMC and SMC are satellites of the Milky Way, M32 is a satellite of Andromeda).

  • Milky Way
  • Andromeda (M31)
  • Large Magellanic Cloud
  • Small Magellanic Cloud
  • Triangulum (M33)
  • M32
  • Sombrero (M104)
  • Pinwheel (M101)
  • Whirlpool (M51a)
  • M64 (Black Eye)
  • M74 (NGC 628)
  • M81
  • M82 (Cigar)
  • M87
  • M100
  • NGC 891
  • NGC 1068 (M77)
  • NGC 1300
  • NGC 1365
  • Centaurus A
  • Cygnus A

Comparing Milky Way and other Galaxies

We learned how you can compare the Milky Way Galaxy to other Galaxies. We learned about the measurements of distances and the best measures of large distances are variable stars. We also looked at Cepheid Meterstick. We also looked at images of barred spiral galaxies. We also looked at the different ways stars orbit. We also learned about star formation in spiral arms.

We engaged with the material by looking at “Galaxy Classification” on page 139-142. During this tutorial we looked at different galaxies and described characteristics.

The article I found is “What Are Elliptical Galaxies?” on space.com.

The article talked about elliptical galaxies and how they are the most abundant type of galaxy. This article discussed Cygus A one of the most popular galaxies. This galaxy is 600 million light year away. The article discussed the most popular galaxy. The article also said how they have detected more spirals than elliptical. The article also talked about the history.

This article was cool to read. I learned a lot of cool new facts and it also talked about facts I learned in class. I think it is really cool that we know so much about galaxies without leaving.


10 Most Fascinating Galaxies of our Universe

The Sombrero Galaxy (also known as M104 or NGC 4594) is an unbarred spiral galaxy in the constellation Virgo. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk. The dark dust lane and the bulge give this galaxy the appearance of a sombrero. The galaxy has an apparent magnitude of +9.0, making it easily visible with amateur telescopes. The large bulge, the central supermassive black hole, and the dust lane all attract the attention of professional astronomers.

2 Black Eye Galaxy

A spiral galaxy in the Coma Berenices constellation, Messier 64, the famous “Black Eye” galaxy or the “Sleeping Beauty galaxy,” has a spectacular dark band of absorbing dust in front of the galaxy’s bright nucleus. It is well known among amateur astronomers because of its appearance in small telescopes.

3 2MASX J00482185-2507365 occulting pair

The 2MASX J00482185-2507365 occulting pair is a pair of overlapping spiral galaxies found in the vicinity of NGC 253, the Sculptor Galaxy. Both galaxies are more distant than NGC 253, with the background galaxy, 2MASX J00482185-2507365, lying at redshift z=0.06, and the foreground galaxy lying between NGC 253 and the background galaxy (0.0008 < z < 0.06). This pair of galaxies illuminates the distribution of galactic dust beyond the visible arms of a spiral galaxy. The heretofore unexpected extent of dust beyond the starry limits of the arms, shows new areas for extragalactic astronomical study. The dusty arms extend 6 times the radii of the starry arms of the galaxy, and is shown silhouetted in HST images against the central and core sections of the background galaxy.

4 The Whirlpool Galaxy

Also known as Messier 51a, M51a, or NGC 5194, the Whirlpool Galaxy is an interacting grand-design spiral galaxy located at a distance of approximately 23 million light-years in the constellation Canes Venatici. It is one of the most famous spiral galaxies in the sky. The galaxy and its companion (NGC 5195) are easily observed by amateur astronomers, and the two galaxies may even be seen with binoculars. The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understanding of galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.

5 Grand spiral galaxy

Also known as NGC 123, this fascinating galaxy is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms rotating about the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas, together wielding such high mass that they dominate the dynamics of the inner galaxy. Invisible are even greater amounts of matter in a form we don’t yet know – pervasive dark matter needed to explain the motions of the visible in the outer galaxy.

6 Supernova 1987A

Two decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years: a doomed star, called Supernova 1987A.This image shows the entire region around the supernova. The most prominent feature in the image is a ring with dozens of bright spots. A shock wave of material unleashed by the stellar blast is slamming into regions along the ring’s inner regions, heating them up, and causing them to glow. The ring, about a light-year across, was probably shed by the star about 20,000 years before it exploded.In the next few years, the entire ring will be ablaze as it absorbs the full force of the crash. The glowing ring is expected to become bright enough to illuminate the star’s surroundings, providing astronomers with new information on how the star expelled material before the explosion.The image was taken in December 2006 with Hubble’s Advanced Camera for Surveys. (Credit: NASA, ESA, and R. Kirshner Harvard-Smithsonian Center for Astrophysics)

7 Galaxy NGC 1512

A barred spiral galaxy located some 30 million light years away toward the constellation Horologium, Galaxy NGC 1512 is bright enough to be seen with amateur telescopes. The galaxy is some 70,000 light years across, which is nearly as large as our own Milky Way galaxy. The core of the galaxy is remarkable for its “circumnuclear” starburst ring, which is an amazing circle of young star clusters that spans some 2400 light years across. Galaxy “starbursts” are episodes of vigorous formation of new stars and are found in various galaxy environments.

8 Galaxy NGC 3370

A dusty spiral galaxy located some 98 million light years away toward the constellation Leo, the center of NGC 3370 shows well delineated dust lanes and an uncommonly ill-defined nucleus. This view of NGC 3370 was obtained by the Hubble Space Telescope using the Advanced Camera for surveys and is sharp enough to identify individual Cepheid variable stars in the galaxy. Cepheid variable stars are used to establish extragalactic distances. In 1994, a Type Ia sypernova exploded in NGC 3370.(Credit: NASA, The Hubble Heritage Team and A. Riess STScI)

9 M81

The big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth. This superbly detailed view reveals its bright nucleus, grand spiral arms and sweeping cosmic dust lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane runs straight through the disk, below and right of the galactic center, contrary to M81’s other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 (aka NGC 3031) has yielded one of the best determined distances for an external galaxy — 11.8 million light-years.

10 Hoag’s Object

A non-typical galaxy of the type known as a ring galaxy, the appearance of Hoag’s Object has interested amateur astronomers as much as its uncommon structure has fascinated professionals. Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark. How Hoag’s Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include a galaxy collision billions of years ago and perturbative gravitational interactions involving an unusually shaped core. The above photo taken by the Hubble Space Telescope in July 2001 reveals unprecedented details of Hoag’s Object and may yield a better understanding. Hoag’s Object spans about 100,000 light years and lies about 600 million light years away toward the constellation of Serpens. Coincidentally, visible in the gap is yet another ring galaxy that likely lies far in the distance.


What are the most popular galaxies for which we have images? - Astronomy

I think the Hubble Ultra Deep Field photo is amazing . the implied numbers of galaxies and stars are mind-boggling, and hence my question.

The field of the HUDF is said to be about 1/10 the diameter of a full moon. To put the possibilities in perspective of a number that might be a little more comprehensible, how many photos that size (1/10 the Moon's diameter) would it take to cover the entire sphere of the sky?

The answer to this question relies on something called angular size, which shows up all over in astronomy. In astronomy, it often happens that you are looking at a picture of something and you don't know how far away it is, so you can't say accurately how big it really is. However, you know how big it looks. If you measure the angle between two lines that stretch from your eye out to both edges of the thing you're looking at, that is the object's angular size.

Angular size is given in units of degrees, arcminutes and arcseconds. Most of us are used to measuring angles in degrees: there are 360 degrees in a circle, the angles of a triangle add up to 180 degrees, etc. Minutes and seconds are just smaller units of angle. There are 60 arcminutes in a degree, and 60 arcseconds in one arcminute.

To measure the area of something on the sky, we use square degrees, square arcminutes, etc. These are more complicated than normal "square" units that we're used to (such as square inches or square miles). Square arcminutes have to account for the fact that when we deal with angular size, it is as if everything has been projected onto the surface of a sphere, so there is some curvature. It turns out that the sphere of the sky is 41,253 square degrees. This corresponds to 148,510,800 square arcminutes.

According to the Space Telescope Science Institute, the Hubble Ultra Deep Field has an angular size of 11.5 square arcminutes. That means that it would take 12,913,983 Deep Field images to cover the entire sphere of the sky!

Just for fun, let's calculate roughly how many stars that implies in the observable universe: The ultra deep field image has about 10,000 galaxies in it. If we assume that each galaxy has 100,000,000,000 (100 billion) stars, then the approximate number of stars in the visible universe is absolutely staggering: 123,000,000,000,000,000,000

123 quintillion stars! That's 123 billion billion. 123 million million million.

It is easy to get lost in these mind-boggling numbers. They are so overwhelmingly huge that the human mind cannot rationalize them. But at the very least, we can get a sense of things. The Ultra Deep Field shows us just how big the universe is and how small and fragile we all are.

About the Author

Ryan Anderson

Ryan is a research fellow at USGS in Flagstaff, AZ and is a member of the Curiosity ChemCam team. He also loves explaining all aspects of astronomy. Check out his blog!


When asteroids photobomb galaxies

Those streaks are asteroid trails, caught in front of the distant galaxies in the Abell 370 galaxy cluster. The effect of parallax causes the asteroid trails to appear curved. Click here for high-res version. Image via ESA.

Asteroids are common in our solar system, and astronomers find new ones frequently. The first two images on this page, though, show how astronomers have found asteroids while looking for something else, in this case galaxy clusters billions of light-years away. They came across the asteroids by chance. You could say that the asteroids photobombed the galaxy photoshoot!

You can help astronomers find asteroids in this way, too. More about that newly launched Zooniverse project below.

Asteroids – or actually asteroid “trails,” created as the asteroids move in their orbits, closer to us than the stars and galaxies beyond – are seen in the first two images on this page. The images were released by the European Space Agency (ESA) on June 24 and 25, 2019, in conjunction with the annual Asteroid Day festivities in the days leading up to and on June 30.

The trails are created by the movement of the asteroids, as seen in multiple exposures taken by the Hubble Space Telescope. Those multiple exposures can then be combined to create a single image, such as those you see above and below. The images were taken as part of the Frontier Fields program, which aims to use the Hubble Space Telescope to its maximum capabilities.

The astronomers were observing huge galaxy clusters, containing thousands of galaxies as well as hot gas and dark matter. The asteroids were found accidentally. And now you can participate in a project that aims to find them, intentionally. Keep reading.

Asteroids are members of our solar system. Because they’re relatively close to us, we see them move apart from the more distant background of space. This image from the Hubble Space Telescope shows the distant galaxy cluster Abell 370. There are also 20 asteroid trails in this image, resulting from 7 individual asteroids, 5 of which had never been seen before because they were too faint. The curved or S-shaped trails stand out sharply against the background of galaxies. Click here for high-res version. Image via ESA.

How you can help astronomers find asteroids. This month, astronomers launched a new citizen-science project called the Hubble Asteroid Hunter, part of the larger Zooniverse project. Astronomers, planetary scientists and software engineers at ESA and other institutions initiated Hubble Asteroid Hunter. Here’s what ESA said when it announced the new project on June 24:

… a team of astronomers, planetary scientists and software engineers based at ESA and other research institutes has launched a new citizen science project: the Hubble Asteroid Hunter. The project was developed as part of the Zooniverse – the world’s largest and most popular platform for people-powered research.

The new project features a collection of archival Hubble images where calculations indicate that an asteroid might have been crossing the field of view at the time of the observation. Everyone can participate! By identifying the asteroids potentially present in these images and marking the exact position of their trails, you too can help the team improve the asteroid orbit determination and better characterize these objects. Precise knowledge of the orbit is particularly important for so-called near-Earth asteroids, those potentially flying close to our planet.

ESA said the citizen-science project particularly useful for finding near-Earth asteroids, those that could pose a possible risk to our planet. Astronomers are always on the lookout for those, since an impact from one could be catastrophic.

Astronomers know of hundreds of thousands of asteroids in our solar system. The current count is 796,059, according to NASA. Yet we also know there are still many more asteroids waiting to be discovered.

And you can help. Click here to go to Hubble Asteroid Hunter.

You can participate in projects like Hubble Asteroid Hunter. Click here to learn how. The goal is to find new asteroids in archived images, including near-Earth asteroids that could potentially pose a threat. Image via DepositPhotos/Popular Science.

Bottom line: Although they weren’t specifically looking for them at the time, astronomers found some bonus asteroids while taking deep-space images of distant galaxy clusters. You can participate in a similar project via Hubble Asteroid Hunter.


6 Centaurus A

To the untrained eye, it might be difficult to distinguish Centaurus A as anything remarkable, but when you take a closer look, there&rsquos something peculiar going on here. Centaurus A is large by galaxy standards, and large galaxies often come in one of two flavors: spiral and elliptical. But when astronomers took a look at this galaxy using radio imaging to peer through the veil of dust, they revealed a spiral hidden underneath. This is quite odd, since galaxies are generally one or the other. It is the only elliptical galaxy we&rsquove ever found that has spiral arms. The theory is that Centaurus A absorbed a spiral galaxy some millions of years ago, but such mergers don&rsquot often&mdashor ever, really&mdashleave the spiral arms intact, so we have no clue what is happening here.


Help astronomers find 'baby' galaxies that give birth to new stars

A new citizen science project, led by astronomers at the University of Minnesota, is asking volunteers to help them with web classifications of galaxy spectra to find "baby" galaxies that are giving birth to new stars.

The project, named Galaxy Nurseries, marks the 100th project and 10-year anniversary of Zooniverse, the world's largest and most popular people-powered research platform.

"To celebrate the 100th project of Zooniverse, we are issuing a special challenge to the public to help us complete this new project in just 100 hours," said Claudia Scarlata, lead researcher on the Galaxy Nurseries project and University of Minnesota physics and astronomy associate professor. "Without help from the public, this project could have taken our team a year to complete the 40 classifications for each object."

The Zooniverse online platform runs on support from volunteers, which now number in the hundreds of thousands worldwide. These volunteers act as armchair scientists, helping the team with their online research from the comfort of their own homes.

Funded by NASA and the National Science Foundation (NSF), the main goal of this new Galaxy Nurseries project is to discover thousands of new baby galaxies in the distant Universe using the light they emitted when the Universe was only half of its current age. Accurately measuring the distances to these galaxies is crucial, but this is not an easy task. To measure distances, images are not sufficient, and researchers need to analyze galaxy spectra.

A spectrum is produced by decomposing the light that enters a telescope camera into its many different colors (or wavelengths). This is similar to the way that water droplets split white light into the beautiful colors of a rainbow after a storm.

The horizontal rainbows above show the spectra for the two objects on the left. The beautiful spiral galaxy at the center of the image is seen at it was 4 billion years ago. Researchers can say this because they see an emission line from hydrogen in its spectrum (indicated with an arrow). This emission line allows them to measure the galaxy’s distance. Credit: University of Minnesota

This project uses the Wide Field Camera 3 carried by the Hubble Space Telescope to capture both images and spectra of hundreds of regions in the sky. The data allows researchers to find new galaxies (from the images) and simultaneously measure their distances (using the spectra).

Researchers find galaxies by identifying features called "emission lines" in galaxy spectra. Emission lines appear as peaks in the spectrum and are produced when the presence of certain atomic elements in a galaxy (for example oxygen, or hydrogen), cause it to emit light much more strongly at a specific wavelength.

"The real trick is finding the emission line features in the galaxy spectra," Scarlata said. "Like many modern scientific experiments, we have written computer code that tries to identify these lines for us, but because our automatic line finder is only a machine, the code produces many bogus detections. It turns out that the visual processing power and critical thinking of people is much better than a computer in this case."

With help from Zooniverse volunteers, the researchers can eliminate the false positives and find galaxies that are some of the youngest and smallest that have ever been discovered.

Citizen scientists receive a tutorial on the Zooniverse platform before beginning their work. Together, the citizen scientists will examine more than 10,000 images from the Hubble Space Telescope. If citizen scientists are unsure about their classifications, the platform includes a discussion forum feature where they can talk with other citizen scientists.

"These classifications from citizen scientists will also be used to create a next-generation galaxy and line detection algorithm that is much less susceptible to being fooled and generating spurious detections," Scarlata said. "The work of all of these citizen scientists will be very valuable for the new NASA missions launched in the next decade."

Researchers find galaxies by identifying features called “emission lines” in galaxy spectra. Credit: University of Minnesota

To begin classifying images for the Galaxy Nurseries project, visit the Zooniverse website.

Zooniverse co-founder and University of Minnesota physics and astronomy associate professor Lucy Fortson said this new project highlights the great work of Zooniverse and citizen science.

"Over the past 10 years, the volunteers on Zooniverse have enabled a tremendous amount of science to be accomplished, including more than 100 peer reviewed papers," Fortson said. "But what amazes me the most is the dedication of our volunteer community. As we launch our 100th project, it is a real message of hope that so many people are interested in participating in the process of science."

Although it began as an astronomy platform, Zooniverse now features a number of international projects, covering fields ranging from humanities and biology, to the hugely popular ecology initiative, Penguin Watch.

Zooniverse is led by the University of Oxford and Chicago's Adler Planetarium in close collaboration with the member institutions of the Citizen Science Alliance, with particular leadership from the University of Minnesota-Twin Cities and the University of Portsmouth.

"Over the past 10 years, the volunteers on Zooniverse have enabled a tremendous amount of science to be accomplished, including more than 100 peer reviewed papers," Fortson said. "But what amazes me the most is the dedication of our volunteer community. As we launch our 100th project, it is a real message of hope that so many people are interested in participating in the process of science."

Although it began as an astronomy platform, Zooniverse now features a number of international projects, covering fields ranging from humanities and biology, to the hugely popular ecology initiative, Penguin Watch.


The Top 10 Telescopes of All Time

Humans have been looking to the heavens for as long as we have had stories to tell about them. But the way we look up has come quite far in the past 400 years, since Galileo Galilei first pointed a spyglass to the sky.

In honor of the 400th anniversary of the telescope, Popular Science looks back on the top 10 observatories on Earth and beyond.

Gemini Observatory

Two eyes are better than one. The Gemini Observatory’s twin optical/infrared telescopes are an ocean apart, yet together they can access the entire sky. Gemini South is located at almost 9,000 feet in the Chilean Andes Gemini North (pictured) sits atop the dormant volcano Mauna Kea, home to an international community of telescopes peering at the night skies through Hawaii’s excellent atmosphere. Seven countries own Gemini, whose scientists make it a point to keep the telescope’s technology fresh — the observatories even have a “sputtering chamber” that applies silver coatings on the Gemini mirrors to increase their infrared capabilities.

European Southern Observatory

The observatory’s 3.5-meter scope, the dryly named New Technology Telescope, was the first telescope in the world to have a computer-controlled main mirror. Even amateur scopes now have that technology. The ESO’s suite of telescopes in Chile’s Atacama Desert also includes the Very Large Telescope array (pictured), Europe’s flagship observatory. The ESO is also home to Europe’s portion of the Atacama Large Millimeter/sub-Millimeter Array, known as ALMA, an intercontinental collaboration with North America, east Asia and Chile. ALMA will be the highest observatory on Earth and the world’s most advanced radio astronomy observatory. Which takes us to the next top observatory …

National Radio Astronomy Observatory (NRAO)

The observatory’s several sites include the Green Bank Telescope, the Very Large Array (pictured), the Very Large Baseline Array and the future U.S. portion of ALMA. Scientists have recently used data from Green Bank to search for the frequencies of molecules in interstellar space. The Very Large Array’s boring name belies its stupendous size: it consists of 27 radio antennas, each weighing 230 tons and reaching 82 feet in diameter. The array, in the desert south of Socorro, New Mexico, combines to give the resolution of a 22-mile-wide antenna. Some people might recognize it from the movie Contact.

Chandra/Spitzer Space Telescopes

NASA’s other famous Great Observatories (besides the Hubble Space Telescope) have provided glimpses into a universe we otherwise couldn’t see. The Chandra X-Ray Observatory’s elliptical orbit, which takes it far away from Earth, gives it a better view of the highest-energy regions of space, like the aftermath of supernovae. Images from Chandra have helped scientists better understand pulsars and nebulae. The Spitzer Space Telescope (pictured), an infrared instrument named for the father of the space telescope, Lyman Spitzer, gives scientists a glimpse of the universe’s cooler objects, including small stars and extrasolar planets. Both telescopes have made discoveries that would be impossible from Earth.

Corot/Kepler Space Telescopes

These scopes, one French, one American, are searching for other worlds in the Goldilocks zones of faraway solar systems — where the temperature is just right for liquid water. NASA’s Kepler telescope launched last month, and its dust cover was just removed this week so it can start making observations. Pictured is the final inspection of the honeycombed primary mirror of the Kepler telescope. Corot, or COnvection, ROtation and planetary Transits, is operated by the French and European space agencies. It has already made groundbreaking discoveries since its launch in December 2006, including the February 2009 announcement of a distant, tiny planet, less than twice the size of Earth, orbiting a Sun-like star once every 20 hours.

W. M. Keck Observatory

Keck’s twin 10-meter, 8-story, 300-ton telescopes are as famous for their design as their discoveries. Each primary mirror is composed of 36 hexagonal segments that work together as one single piece of glass — a revolutionary engineering feat that allows for massive mirrors. The Keck telescopes, perched on Mauna Kea, remain the world’s largest optical and infrared telescopes. They have helped scientists make some amazing discoveries: the presence of galaxies at the edge of the universe studying supernovas to determine the universe’s expansion rate the nature of gamma-ray bursts and, most recently, planets around other stars.

Mount Wilson Observatory

From the mule trains used to hoist the 60-inch mirror to the mountaintop to the cold nights Edwin Hubble spent rewriting our knowledge of the cosmos, Mount Wilson represents the evolution of the modern observatory, and one of the most important scientific places in history. George Ellery Hale’s 60-inch scope, which is no longer used for research, was used for studies of the spectral classification of stars, which forms the basis of modern astronomy. The 60-inch Hale telescope was the largest in the world 100 years ago, but within 10 years, it was replaced by a 100-inch scope next door. Using the 100-incher (pictured en route to the summit in 1917), Edwin Hubble discovered that the smudges of “nebulae” in the sky were actually distant galaxies that the universe is expanding and that the speed of that expansion is commensurate with a Big Bang creation. Mount Wilson was the premier observatory in the world for 40 years, until L.A.’s brightness led astronomers to look south, toward …

Palomar Observatory

Palomar’s 200-inch Hale telescope helped revolutionize modern astronomy — and modern baking. Mirror makers spent nearly $1 million — in 1934 dollars — and still couldn’t make a big enough quartz mirror. George Ellery Hale, who shepherded Palomar’s creation as he had Mt. Wilson’s, approached Corning Glass Works of upstate New York and asked for a 200-inch mirror made of a new glass blend called Pyrex. Changes in temperature make Pyrex expand and contract less than regular glass, so a Pyrex mirror is less prone to distortion problems, which had plagued Hale’s 100-inch scope on Mt. Wilson. After World War II-related delays, first light came Jan. 26, 1949. Edwin Hubble was the first to peer through the looking glass. A year later, a companion 48-inch scope began the first Palomar Observatory Sky Survey, which mapped the entire northern sky. The catalog would later become the basis for the Guide-Star Catalog used by the Hubble Space Telescope. After three quarters of a century, Palomar is still making new discoveries. In 2007, scientists announced a new “adaptive optics” system to sharpen pictures taken from Palomar. The resolution exceeds the Hubble Space Telescope’s by a factor of two.

Galileo’s Telescope

Galileo Galilei didn’t invent the telescope he probably wasn’t even the first person to point a spyglass skyward. But his powerful telescope design allowed him to see farther than anyone had before — or at least anyone who had published his findings. His discoveries shook the foundations of Europe, earning him the title “Father of Modern Science.” With his 1609 telescope, he examined the moon, discovered four of Jupiter’s moons, watched a supernova, discovered sunspots and verified the phases of Venus. He was also convicted of heresy for advocating a heliocentric view of the universe. One of Galileo’s two remaining telescopes went on display this month for its first and only exhibition outside Italy, at the Franklin Institute in Philadelphia.

Most Popular Astronomy Topics?

If I were to give a presentation on the three most popular, or publicly discussed,subjects in astronomy, what would those subjects be?

1. Black Holes?
2. Killer Asteroids?
3. Pluto (!)

My audience won't be technically-minded folks like us, but neighbors who are intelligent and curious as to what I do at night .

#2 StarStuff1

#3 Dave Mitsky

Comets and supernovae might be good topics.

#4 Skylook123

#5 jmandell

#6 pepit

#7 hokkaido53

#8 SusanY

My neighbours are also curious about what I do all night out there in the dark – and I find that a general overview of the birth, life and death of stars, including that of the Sun, is a jaw-dropper for them. The sheer scale of it all - time, temperatures, distance, size - boggles the mind. Plus it covers all the exciting stuff like supernovae, neutron stars, black holes, and by the time we get to the fact that every atom in our bodies was forged in the heart of a star, they are all agreeing that it’s not such a strange thing to spend all night out in the dark with your telescope!

The most satisfying thing for me is when I see the penny drop… they all know the Southern Cross and many have noticed that one of its stars is decidedly red, so when they find out why it’s red – that’s the penny-dropper because they realise that you can partake of all this incredible stellar evolution simply by looking up.

#9 MikeBOKC

#10 youngamateur42

#11 GeneT

#12 -Starfighter-

#13 csrlice12

The planets of the Solar system seem to fascinate everyone.
People also find topics about aliens interesting, but don't talk about the too crazy ideas (ancient aliens) .

#14 Matthew Ota

#15 penguinx64

2 cloud bands on Jupiter
Moon craters
Some sort of ring on Saturn
Orion nebula
Pleiades cluster

That's a pretty good night.

#16 hokkaido53

2 cloud bands on Jupiter
Moon craters
Some sort of ring on Saturn
Orion nebula
Pleiades cluster

That's a pretty good night.

Yes, it is. This summer, Saturn will be in view where I live, along with the Milky Way and all those globulars. Interesting things to show the neighbors after the barbecue.

#17 Ptarmigan

Everyone always seems to be pretty interested in Saturn. But I show some neighbors the Orion Nebula, and bright star clusters and they never cease to be amazed. The galaxies are a bit of a different story, not as much of a wow factor, unless at dark skies. Jupiter is always interesting, when I explain to them that the little pin points of light are the moons.

#18 csrlice12

#19 tedbnh

Just my opinion, but I think the list of most popular topics tends to be populated by items that the mainstream media finds "titillating". However from an educational standpoint for my neighbors, these topics tend to be dead-ends. It's hard to make "black holes" the thing that gets you interested in observational astronomy.

Go for the solar system. They can actually see all these things!

1) Titan. You can show them how Cassini got to Saturn and then send the Huygens probe down to the surface of Titan. We have pics of the rivers of liquid methane, a movie of the surface taken by the probe as it swung down through the clouds. The river systems on Titan look just like those on Earth, but they contain liquid methane at -280 degrees F. As Carolyn Porco reminds us in her Ted talk, it's the only place mankind has actually touched in the outer solar system (except the odd comet).

2) Saturn. Cassini images and movies are fascinating beyond belief.

3) The Moon. Why does it show phases?

4) Jupiter. Show them Galileo's notebook where he sketched the locations of the moons for a month.

They only think they want to know about killer asteroids. You will convince them otherwise! :-)


Hubble sees most distant galaxies

The pictures were acquired by the HST's new Wide Field Camera 3 (WFC3).

This highly sensitive camera can see starlight from far-off objects - light that has been "stretched" by the expanding Universe.

Scientists who have analysed the new images say the galaxies they reveal could be the most distant yet observed.

Two UK-based teams of scientists published their analyses in the Monthly Notices of the Royal Astronomy Society.

WFC3 was added to Hubble as part of a upgrade and repair mission carried out by the space shuttle Atlantis earlier this year.

The camera is sensitive to infrared light, which has wavelengths about twice as long as visible light and cannot be detected by the human eye. It is described as "beyond red".

Dr Andrew Bunker, an astronomer from Oxford University, led one of the teams that studied the new pictures.

He explained that the camera had captured "light that started its life in the visible and has been stretched to longer wavelengths, so it is redder".

Some of the new images are from the region of sky known as the Hubble Ultra Deep Field.

Dr Bunker and his colleagues first analysed this five years ago using Hubble's Advanced Camera for Surveys (ACS).

"We're able to use this new data - taken at long wavelengths - and combine it with the existing data that was taken in the visible [spectrum]," he told BBC News.

"We make a colour image with the long wavelengths and the short wavelengths and look for a very distinctive signature."

That signature is based on colour. The redder an object appears, the more its light has been stretched, and the further away it is.

Capturing this stretched starlight gives astronomers a glimpse back in time to the early Universe.

Dr Daniel Stark, a postdoctoral researcher at the Institute of Astronomy in Cambridge, also worked with the teams reporting their work on Tuesday.

He said: "We can now look even further back in time, identifying galaxies when the Universe was only 5% of its current age - within one billion years of the Big Bang."

But Dr Bunker said that the exact distance to the galaxies was yet to be confirmed.

"The evidence on the basis of the images - the colours - is very strong," he told BBC News.

"These are some of the most distant, and perhaps the most galaxies distant yet seen."

But to confirm this, he said, astronomers would need to study the spectrum of light from each galaxy, to measure its "redshift". This is a measurement of how much the light from a distant object has been stretched.

Professor Jim Dunlop from the University of Edinburgh co-led a team with Dr Ross McLure, which also studied the Hubble data. He said: "These new observations are likely to be the most sensitive images Hubble will ever take."

The follow-up studies, he added, would be possible when Hubble's successor, the James Webb Space Telescope (JWST), was launched in 2014.

Dr Bunker described the JWST as the "next quantum leap in telescope technology".

"It has a greater collecting area and is optimised to work in the infrared," he explained.

"With JWST, we'll be able to take the spectra of many objects at once. This will be wonderful - instead of [analysing] the odd galaxy, we'll be able to build up meaningful samples and do real science."

In 2007, a group led by Professor Richard Ellis from the California Institute of Technology reported the discovery of light from galaxies at similar, and perhaps even longer, distances than the ones reported on Tuesday.

He and his team employed a technique called gravitational lensing, which uses of the gravity of relatively nearby objects to magnify the light coming from much more distant objects.

Dr Bunker, who has worked with Professor Ellis's team in the past, explained that the scientific community was still actively studying the Caltech team's "very exciting" results.

"The galaxies they looked at were really incredibly faint," he said.

"And they looked at the glow of gas, which is the very limit of what is feasible and difficult for the community to confirm."

He said that he expected Professor Ellis's results eventually to be confirmed and said that all the studies were "complementary".