Posted on by Fraser Cain

Solar System Pictures

Diagram of the Solar System. Image credit: NASA

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This is a a diagram of the Solar System. It was released shortly before the International Astronomical Union made its final decision about whether Pluto should be a planet or not. In the end, they decided that Pluto is not a planet. But for a few days, it was possible that there would be 11 planets in the Solar System, including Pluto, Eris and the asteroid Ceres. This image of the Solar System shows them all with the Sun.

Pictures of all the objects in the Solar System. Image credit: NASA/JPL
Pictures of all the objects in the Solar System. Image credit: NASA/JPL

This is a montage photo of the Solar System, with a picture of a Sun and all the planets, as well as all the moons in the Solar System. This lets you see just how many objects there really are in the Solar System.

Montage of the Solar System. image credit: NASA/JPL
Montage of the Solar System. image credit: NASA/JPL

This is another montage of the planets, dwarf planets, comets and asteroids in the Solar System. It’s one of the older Solar System pictures that we’ve seen.

Planets in the Solar System. Image credit: NASA/JPL/IAU
Planets in the Solar System. Image credit: NASA/JPL/IAU

Here’s a Solar System image with all the planets correctly categorized. In this, we can see a picture of Pluto, Ceres and Eris are correctly designated as dwarf planets.

Want more images of planets? Here are some pictures of Mars, pictures of Venus, pictures of Saturn, pictures of Pluto, and pictures of Jupiter. Here’s an article about a 3D Solar System.

One of the best resources for photographs of the Solar System is NASA’s Planetary Photojournal. You can also check out Hubble’s photographs of the Solar System.

We have recorded a whole series of podcasts about the Solar System at Astronomy Cast. Check them out here.

Posted on by Fraser Cain

Diagram of the Solar System

Diagram of the Solar System. Image credit: NASA

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This image contains all of the largest objects in the Solar System. You can print this diagram of the Solar System, as well as this handy list of all the planets.

The Sun – The central star in the Solar System

Mercury – The first planet in the Solar System. It’s also the smallest planet in the Solar System. Mercury takes just 88 days to complete an orbit around the Sun.

Venus – The second planet from the Sun. In many ways, Venus is a twin to our own Earth. It has nearly the same size and mass as Earth, but the thick atmosphere on Venus makes surface temperatures hot enough to melt lead. Venus is also unusual because it rotates backwards to all the other planets.

Earth – Our home planet, the third planet from the Sun. Earth is the only planet in the Solar System known to support life. This is because we are at just the right distance from the Sun so that our planet doesn’t get too hot or too cold. We also have one moon – the Moon.

Mars – Mars is the fourth planet from the Sun, and is much smaller and colder than the Earth. Temperatures on Mars can rise to 20-degrees C, but dip down to -140-degrees C in the northern winters. Mars is thought to be the best candidate for life elsewhere in the Solar System. Mars has two small, asteroid-shaped moons: Phobos and Deimos.

Ceres – Ceres is the first dwarf planet in the Solar System, and the largest member of the asteroid belt.

Jupiter – Jupiter is the 5th planet from the Sun, and the largest planet in the Solar System. Jupiter has as much mass as 2.5 times all the rest of the planets combined – almost all of this mass is hydrogen and helium; although, scientists think it has a solid core. Jupiter has at least 63 moons.

Saturn – Saturn is the 6th planet from the Sun, and is well known for its beautiful system of icy rings. Saturn is almost as large as Jupiter, but it has a fraction of Jupiter’s mass, so it has a very low density. Saturn would float if you could find a tub of water large enough. Saturn has 60 moons at last count.

Uranus – Uranus is the 7th planet from the Sun, and the first planet discovered in modern times; although, it’s just possible to see with the unaided eye. Uranus has a total of 27 named moons.

Neptune – Neptune is the 8th and final planet in the Solar System. Neptune was only discovered in 1846. It has a total of 13 known moons.

Pluto – Pluto isn’t a planet any more. Now it’s just a dwarf planet. Pluto has one large moon, called Charon, and then two smaller moons.

Eris – The next dwarf planet in the Solar System is Eris, which was only discovered back in 2003. In fact, it was because of Eris that astronomers decided to reclassify Pluto as a dwarf planet.

I hope you find this diagram of the Solar System helpful.

Reference:
NASA Solar System Exploration Guide

Posted on by Nancy Atkinson

Ancient Galactic Magnetic Fields Stronger than Expected

Spiral galaxy M 51 with magnetic field data. Credit: MPIfR Bonn

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The origin of magnetic fields in our universe is a mystery. But magnetic fields are a key part of the interstellar medium and scientists are finding they may play a major role in galactic formation, such as helping to form the spiral arms of galaxies. Until recently, however scientists believed the strength of galactic magnetic fields increased over time as galaxies matured, and in the early universe, these magnetic fields were initially very weak. But, recently a team of scientists looking back to probe the ancient universe as it existed 8 to 9 billion years ago has found that the magnetic fields of ancient galaxies were just as strong as they are today, prompting a rethinking of how our galaxy and others may have formed.

Using the European Southern Observatory’s 8-meter telescope located in Chile, a team of scientists from the Los Alamos National Laboratory and the Swiss Federal Institute of Technology studied 70 galaxies similar to the Milky Way at optical wavelengths. They combined their data with 25 years of radio wave observations of magnetic fields that measured how far the radio waves were pulled toward the red end of the spectrum, known as “redshift” using Faraday rotation measures.

Serving as a looking glass into the past, the powerful telescope at the European Southern Observatory, adding to the radio rotation measures, allowed the scientists to observe surprisingly high magnetic fields between 8 billion and 9 billion years ago in the 70 galaxies studied. That means that several billion years before the existence of our own sun, and within only a few billion years of the Big Bang, ancient galaxies were exerting the tug of these strong magnetic fields.

“It was thought that, looking back in the past, earlier galaxies would not have generated much magnetic field,” said Philipp Kronberg of LANL. “The results of this study show that the magnetic fields within Milky Way-like galaxies have been every bit as strong over the last two-thirds of the Universe’s age as they are now-and possibly even stronger then.”

Astronomers had thought a mechanism called a dynamo, which transfers mechanical energy into magnetic energy was responsible for galactic magnetic fields. In that case, with the right configuration gas flow could generate a higher magnetic field from a weaker seed field. (Again, we have yet to understand how galactic magnetic fields originally form.) But this new research suggests that the magnetic fields in galaxies did not arise due to a slow, large-scale dynamo effect, which would have taken 5 billion to 10 billion years to reach their current measured levels.

“There must be some other explanation for a much quicker and earlier amplification of galactic magnetic fields,” Kronberg said. “From the time when the first stars and galaxies formed, their magnetic fields have probably have been amplified by very fast dynamos. One good possibility is that it happened in the explosive outflows that were driven by supernovae, and possibly even black holes in the very earliest generations of galaxies.”

This realization brings a new focus on the broader question of how galaxies form. Instead of the commonly held view that magnetic fields have little relevance to the genesis of new galaxies, it now appears that they are indeed important players. If so, strong magnetic fields a long time ago are one of the essential ingredients that explain the very existence of our galaxy and others like it.

Original News Source: Los Alamos National Lab

Posted on by Ian O'Neill

Polaris Brightness Variations are Revived, Astronomers Mystified

Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. Polaris itself is a Cepheid type variable star. Artists impression. Credit: NASA
Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. Polaris itself is a Cepheid type variable star. Artists impression. Credit: NASA

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Polaris is a well known Cepheid variable, but its periodic brightness variations have been steadily decreasing in amplitude for the last hundred years. Around the beginning of the 20th Century, Polaris’ brightness fluctuated every four days by 10%. Only ten years ago this variation had dropped to 2%, leading astronomers to believe this steady decline in the variability of the star was about to end. That was until recent observations uncovered an increase in variability to 4%. Polaris is an odd star in that it is a Cephid variable with a declining variability, and now astronomers are baffled as to why the brightness fluctuation has been revived…

Polaris (a.k.a. the North Star or Pole Star) has helped mankind navigate the globe since ancient times. Always positioned around the North Polar axis of the Earth, Polaris has also provided material for literature, poetry and religion. In astronomical terms it is also significant as it is a Cepheid variable with a regular variation in brightness, although it is the only Cepheid variable known that has been decreasing in brightness for the last several decades. But to complicate matters even further, this Type 1a supergiant (approximately 4-5 solar masses and 30 solar radii) appears to have been rejuvenated, and the vibrations have increased, varying in brightness by 4 %.

This discovery comes after observations made by Hans Bruntt from the University of Sydney and his international collaboration. Dr Alan Penny, co-investigator from the University of St. Andrews, UK, will present the team’s findings at his university’s “Cool Stars 15” conference this week.

In reality, the astronomers had focused their attention on Polaris in the hope to catch the point at which its variations ceased completely, only to find they had increased. “It was only through an innovative use of two small relatively unknown telescopes in space and a telescope in Arizona that we were able to discover and follow this star’s recovery so accurately,” Penny said. He was using the SMEI space camera, usually applied for solar-terrestrial observations of the solar wind, but he used it to accurately survey the night sky for Cepheid variables. At the same time, Bruntt was using a small telescope attached to NASA’s retired infra-red space telescope (WIRE) set up to study Polaris for a short period. When Penny noticed the strange recovery of Polaris in his SMIE data, it was compared with Bruntt’s WIRE data. It was therefore confirmed that Polaris’ vibrations had been revived.

H. Bruntt et al. 2008
Decrease over 100 years of amplitude of 4-day light variation of Polaris and of the increase since 2000. Credit: H. Bruntt et al. 2008

Backing up Penny and Bruntt, Professor Joel Eaton (Tennessee State University), who was using the AST automated spectroscopic telescope located in Arizona, noticed variations in the plasma velocity on the surface of Polaris. These measurements showed the brightness variations were correlated with expansion and contraction effects through the body of the star.

These observations are both exciting and perplexing. Although the variations observed in Cepheid variables are poorly understood, the vast majority of these “standard candles” do not change in brightness, let alone revive themselves. It would appear Polaris is undergoing a change that isn’t predicted by the standard model for stellar evolution, so the team of astronomers will be quick to follow up these observations with some theory as to what is causing the changes inside Polaris…

Sources: Physorg, arXiv

Posted on by Fraser Cain

Model of the Solar System

Everyone seemed to enjoy the answer to my daughter’s question, “what’s the biggest star?”, so I thought I’d give you another insight into space science at the Cain household. A couple of months ago, we built a scaled map of the Solar System. I thought I’d share my process and resources with you, and throw in a few cute pictures of the kids. So come on, let’s build a solar system scale model in your neighborhood. And for those who might be interested, we also put up links of amazing Solar System collectibles from Amazon.com. Your kids will surely enjoy them!

This project happened when I casually mentioned to Chloe that it might be fun to build a scale model of the solar system. You know, some day, when we had time. Chloe and Logan thought it was a great idea, and even though there was half a metre of snow on the ground, it had to happen… right now!

We decided that we wanted to put the Sun in Chloe’s room, and then put all the planets to scale, so that we could walk to Chloe’s school (about a kilometer away), and have all the planets fit nicely – we even included Pluto (which will always be a planet in our hearts).


I found a great calculator that lets you calculate various scale model versions of the Solar System. You put in the size for the Sun and then it calculates both the diameters of the scale model versions of the planets, as well as the scale distances.

Solar System Model

We were really fortunate. A version of the Solar System scale model that fit within the distance from our house to Chloe’s school allowed for a Sun that could be cut out of a single sheet of printer paper. I used a protractor to measure out the circle for the Sun, and then cut it out. While the kids were colouring it yellow, I made tiny versions of all planets.

Here are the sizes:

Object Size (mm) Size(in)
Sun 200 7.8
Mercury 0.6 0.0275
Venus 1.7 0.0684
Earth 1.8 0.072
Mars 0.9 0.0382
Jupiter 20 0.7892
Saturn 16.7 0.6586
Uranus 6.7 0.2655
Neptune 6.5 0.257
Pluto 0.3 0.012

Then we put our mock planets out into their proper orbits using clear sticky tape. With the Sun just inside Chloe’s room, Mercury was at the top of the stairs. Venus was just outside our front door. Earth at the end of our sidewalk. Mars is on a parking sign across the street from our front door. Jupiter is part way down the next block, stuck to a tree. Saturn is on another tree further down that same block. Neptune is on a parking sign 2 blocks further. Uranus is on a fire hydrant. And finally, tiny Pluto was affixed to a power pole just in front of Chloe’s school.

If you want to get really clever, you can even put in tiny moons. For example, you could put in the moons of Pluto: Charon, Nix and Hydra.

Here are the kids with Mars. Look closer, it’s there.

Here are all the distances:

Object Distance (m) Distance (feet)
Sun 0 0
Mercury 8 27
Venus 15 51
Earth 21 71
Mars 32 107
Jupiter 111 367
Saturn 205 673
Uranus 412 1353
Neptune 647 2121
Pluto 850 2787

I was fairly careful measuring distances for the inner planets. But then I just made a rough estimate of my stride length, and used that to mark off the longer distances. Here’s a link to a stride length calculator.

It’s scary to think that a version of Alpha Centauri at this scale would still be 5804.4 km (3606.7 miles) away. That would require a road trip across Canada.

And, now, every day that I walk Chloe to school, we follow the route of our miniature Solar System, and think about just how big the place really is. Even though it’s been a few months since we made our model, most of the planets are still there (we lost Saturn a few weeks back, but we’ll replace it).

Have you built a Solar System scale model for a school project? Let me know how it went and send pictures. Maybe I’ll do a follow up with some more astronomy project ideas.

For extra credit, get your kids to model some of the recently discovered extrasolar planets. Here’s a page that lists their sizes and distances from their parent stars. With so many hot jupiters out there, you could fill a wall with scale versions.

If your kids want to learn more about the Solar System, listen to Astronomy Cast. We did a special tour through each of the planets in the Solar System. Start your tour here with Mercury, then Venus, Earth, Mars, the Asteroid Belt, Jupiter, Jupiter’s Moons, Saturn, Saturn’s Moons, Uranus, Neptune, Pluto, and then the outer reaches of the Solar System.

Posted on by Fraser Cain

What is the Solar System?

Pluto and the rest of the Solar System. Image credit: NASA

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The Solar System consists of the Sun, and everything bound to it by gravity. This includes the 8 planets and their moons, the asteroids, the dwarf planets, all the Kuiper belt objects, the meteoroids, comets and interplanetary dust. Since the gravitational effects of the Sun are thought to reach out almost 2 light-years away – almost half the distance to the next star – there could be any number of objects out there, as part of the Solar System.

There are separate regions in the Solar System. First, there’s the Sun, of course. Then there are the inner terrestrial planets: Mercury, Venus, Earth, and Mars. Then comes the asteroid belt; although, not all the asteroids are located in this region. The largest dwarf planet, Ceres, is located in the asteroid belt. Then come the outer gas giants: Jupiter, Saturn, Uranus, and Neptune. Then comes the Kuiper Belt, which includes 3 more dwarf planets: Pluto, Makemake, and Eris. Beyond the Kuiper Belt is thought to be the Oort Cloud, which could extend out to a distance of 100,000 astronomical units (1 AU is the distance from the Sun to the Earth).

Between the planets are smaller objects which never formed a planet or moon. This can range from microscopic dust, up to asteroids hundreds of kilometers across. Beyond the orbit of Neptune, much of this material is icy.

The solar wind emanating from the Sun blasts through the Solar System, interacting with the planets, and pushing material out into interstellar space. The region where this solar wind blows is called the heliosphere, and where it stops is called the heliopause.

The immediate neighborhood around the Solar System is known as the Local Interstellar Cloud. It has high-temperature plasma that suggests that there were nearby supernovae.

The closest star to the Solar System is the triple star system Alpha Centauri.

Are you wondering how many planets there are in the Solar System, or what is the biggest planet in the Solar System?

One of the best pages about the Solar System is the Nine Planets, and Kids Astronomy has more info for kids.

We have recorded a whole series of podcasts about the Solar System at Astronomy Cast. Check them out here.

Posted on by Tammy Plotner

Observing Alert: Dwarf Nova VY Aquari Re-Brightens

VY Aquari (35" field)

[/caption]According to AAVSO Special Notice #114 prepared by Matthew Templeton and released just a few minutes ago, dwarf nova VY Aquari is now rebrightening and observers are asked to contribute their data. VY Aquari has been fairly quiet since its last superoutburst of 10.2 magnitude on June 30, 2008 and is on the rise again…

“Several observers have reported that the dwarf nova VY Aqr (RA 21 12 09.20 Dec 08 49 36.5) has rebrightened since fading from its initial superoutburst. Although VY Aqr has been classified as a WZ Sge-type dwarf nova, previous superoutburst rebrightenings have not been well-observed. Continued monitoring of VY Aqr for the next several weeks is strongly encouraged. Both visual and CCD time-series observations are needed, the former to track the overall light curve, and the latter to study superhumps and short-term variability. Both positive and fainter-than estimates are valuable, so please continue to monitor VY Aqr if and when it becomes faint again — it may undergo further rebrightenings during this outburst.”

AAVSO Locator Chart
AAVSO Locator Chart
According to Sky & Telescope, a dwarf nova is a type of cataclysmic variable, consisting of a close binary star system in which one of the components is a white dwarf, which accretes matter from its companion. They are similar to classical novae in that the white dwarf is involved in periodic outbursts, but the mechanisms are different: classical novae result from the fusion and detonation of accreted hydrogen, while current theory suggests that dwarf novae result from instability in the accretion disk, when gas in the disk reaches a critical temperature that causes a change in viscosity, resulting in a collapse onto the white dwarf that releases large amounts of gravitational potential energy.

Dwarf novae are distinct from classical novae in other ways; their luminosity is lower, and they are typically recurrent on a scale from days to decades. The luminosity of the outburst increases with the recurrence interval as well as the orbital period; recent research with the Hubble space telescope suggests that the latter relationship could make dwarf novae useful standard candles for measuring cosmic distances.

Thanks to recent studies by R. E. Mennickent (et al): “The tomograms reveal complex emission structures that can be identified with the accretion disc, the bright spot and, in the case of VY Aqr, the secondary star. For the first time, the white dwarf is detected unambiguously in the spectrum of VY Aqr.”

Why not check it out yourself? If you have a GoTo telescope, set it on the coordinates listed above and compare what you see with the wide angle chart (courtesy of AAVSO), then up the magnification and compare the field with the Palomar Sky Survey plate image during minima. We’d love to hear about your experience!

Posted on by Tammy Plotner

The “Jewel Box” by Don Goldman

Jewel Box by Don Goldman

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Since it was first observed in a half inch diameter spy glass by Abbe Nicholas Louis de Lacaille during his visit to South Africa in 1751-2, the Kappa Crucis star cluster (NGC 4755) has intrigued and and confounded astronomers since. Today let’s open John Herschel’s ‘casket of variously coloured precious stones’ and take a closer look at the “Jewel Box”…

Situated about 7500 light years away near a vast, dark cosmic dust cloud known as the “Coal Sack”, the Kappa Crucis star cluster has a Bayer designation even though it is a cluster instead of an individual star. Just one look at this colorful array is to understand how it came to be known as the Jewel Box. Sprinkled across 20 light years of space and maybe perhaps only 7.1 million years old, it is home to red, white and blue giant stars alike. If its brightest star were at the center of our own solar system, it would shine 83,000 times brighter than Sol!

The bright orange star is Kappa Crucis, a standout amongst its hot, vivid blue members. A very young star gone into its red supergiant stage? During mid-1862 a man named Francis Abbott began studying the Jewel Box and his observing notes say; “Certain changes that are apparently taking place in the number, position, and colour of its component stars.” This was some pretty radical thinking since he was going up against the notes of the likes of John Herschel and George Airy. But, as so often is the case, sometimes one astronomer can spot what another one can’t and some 10 years later H.C. Russell took Abbott’s notes to heart – measuring and cataloging 130 of the cluster’s stars. Despite extreme criticism, another observer named R.T. Innes also claimed color change as noted in the classic work “Celestial Objects for Common Telescopes”.

Of course, study did not end there and it went into the early 1900s with Trumpler and then Harlow Shapley. The first significantly important astrophysical paper on this cluster appeared in 1958 and was published by Halton Arp and Cecil van Sant who were trying to find out more about galactic supergiant stars. “The three brightest stars are supergiants… and the red star, are all members of the cluster, then NGC 4755 must be somewhat like h and χ Persei… Since these types of clusters are rare, observational material sufficient to derive a colour-magnitude diagram was obtained.” However, as more stars were revealed and studied, the more confusing the designations became! The years progressed and NGC 4755 became even more understood – and better cataloged.

According to studies of helium, carbon, nitrogen and oxygen abundances done by G. Mathys (et al) “After consideration of the CN abundances in this sample, there is no clear evidence of internal mixing. Only three stars among the non-supergiants seem to show a nitrogen enhancement. Two of them have a fairly low projected equatorial velocity (admittedly, they may be rapid rotators seen pole-on); the third one is a definite fast rotator. In the lower gravity stars some kind of mixing has apparently occurred. The supergiants do not differ significantly from the other programme stars in their respective helium contents. The mean helium abundance for each cluster is close to the standard value, (He/H).”

Studying variable stars within open clusters is extremely important. They are clues as to distance and evolution! In young clusters like the Jewel box, the brighter stars should be variables and should be blue. They should also have started evolution away from main sequence, unlike the low mass stars who just quietly burn away their hydrogen. As we know, one of the principle variable types are the Beta Cepheid stars and studies done by Stankov (et al) show the detection of four new variable stars in NGC 4755. “We give frequency solutions as indicators of the time-scales and amplitudes of the pulsations. NGC 4755-116 is probably a B2 dwarf with a period of 4.2 d whose variability is caused by a spot or g-mode pulsation. NGC 4755-405 can be considered as a new β Cephei star with two pulsation frequencies. For NGC 4755-215 we found one frequency and for NGC 4755-316 three pulsation frequencies; we suggest that both are new slowly pulsating B stars of short period.” These variations may be caused by radial pulsations from an instable hydrogen core and even more studies are needed.

But is there more? Yes. Very recent studies done by C. Bonatto (et al) show the dynamical state of NGC 4755. “We explore the possibility that, at the cluster age, some main sequence and pre-main sequence stars still present infrared excesses related to dust envelopes and proto-planetary discs. The core is deficient in PMS stars, as compared with MS ones. NGC 4755 hosts binaries in the halo but they are scarce in the core. Compared to open clusters in different dynamical states studied with similar methods, NGC 4755 fits relations involving structural and dynamical parameters in the expected locus for its age and mass.”

Did NGC 4755 form from the same molecular cloud? Is it two overlapping clusters? Does the proximity of the Coal Sack influence its visual properties? No matter what the science is behind it, the light that you see now left about the same time the Great Pyramids of Egypt were being built. Let the words of Burnham ring the loudest: “…a brilliant and beautiful galactic duster ranking among the finest and most spectacular objects of the southern Milky Way… The cluster lies in a rich and remarkable region in the Heavens, well worth exploring with low power telescopes and instruments of the rich-field type.”

This week’s awesome image was done by Don Goldman and taken at Macedon Ranges Observatory. We thank you!

Posted on by Ian O'Neill

How do you Weigh a Supermassive Black Hole? Take its Temperature

A composite image of Chandra and Hubble Space Telescope observations of giant elliptical galaxy NGC 4649 (ASA/STScI/NASA/CXC/UCI/P. Humphrey et al.)

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Working out the mass of huge black holes, like the ones hiding in the centre of galactic nuclei, is no easy task and attempts are being made to find novel ways to weigh them. Using data from the Chandra X-ray Observatory, two scientists have confirmed a theory they conceived ten years ago, that the supermassive black holes in the centre of galaxies strongly influence the nature of the gases surrounding them. So, acting like a remote thermometer, Chandra is being used to probe deep into the neighbourhood of these exotic objects, gauging their masses very accurately…

The supermassive black hole at the centre of NGC 4649 is a monster. It is about 3.4 billion times the mass of the Sun and a thousand times bigger than the black hole at the centre of the Milky Way. This fact makes it an ideal candidate to test new methods of measuring the mass of black holes to see how the results correlate with traditional methods. With a high degree of accuracy, scientists have proven that a previously untested theory of weighing black holes works by using the Chandra X-ray telescope.

Until now, supermassive black hole masses have been measured by observing the motions of stars and gas deep inside galactic nuclei, now astronomers are using the gravitational influence of the black hole over the hot gas trapped around the singularity. As the gas is pulled slowly toward the black hole, it is compressed and heated. The bigger the black hole, the higher the peak temperature. Chandra has been used to measure the peak temperature of the gas right in the centre of NGC 4649 to find the derived mass is identical to the mass previously measured by traditional means.

Fabrizio Brighenti from the University of Bologna in Italy, and William Mathews from the University of California at Santa Cruz have been working on this research for the past decade. It is only now, with the availability of a telescope as powerful as Chandra that these observations have been possible.

“It was wonderful to finally see convincing evidence of the effects of the huge black hole that we expected. We were thrilled that our new technique worked just as well as the more traditional approach for weighing the black hole.” – Fabrizio Brighenti

The black hole inside NGC 4649 appears to be in a dormant state; it doesn’t seem to be pulling in material toward its event horizon very rapidly and it isn’t generating much light as it slowly grows. Therefore, using Chandra to indirectly measure its mass by sensing the peak temperature of surrounding matter is required to weigh it. In the early universe, huge black holes such as these will have generated dramatic displays of light. Now, in the local Universe, such black holes lead a more retiring life, making them difficult to observe. This prospect excites the lead scientist on the project, Philip Humphrey. “We can’t wait to apply our new method to other nearby galaxies harboring such inconspicuous black holes,” he said.

Source: Physorg.com

Posted on by Nancy Atkinson

Super-Sensitive, Ultra-Small Device Heightens Infrared Capabilities

Physics Prof. Michael Gershenson with laboratory equipment used to fabricate ultra-sensitive, nano-sized infrared light detector. Credit: Carl Blesch

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A tiny new circuit could make a big difference in the way astronomers can see infrared light. This newly developed nano-sized electronic device is 100 times smaller than the thickness of a human hair, and is sensitive to faint traces of light in the far-infrared spectrum, well beyond the colors humans see. Infrared light makes up 98% of the light emitted since the Big Bang. Better detection methods with this new device should provide insights into the earliest stages of star and galaxy formation almost 14 billion years ago.


“In the expanding universe, the earliest stars move away from us at a speed approaching the speed of light,” said Michael Gershenson, professor of physics at Rutgers and one of the lead investigators. “As a result, their light is strongly red-shifted when it reaches us, appearing infrared.”

But Earth’s thick atmosphere absorbs far-infrared light, and ground-based radio telescopes cannot detect the very faint light emitted by these far-away stars. So scientists are proposing a new generation of space telescopes to gather this light. But new and better detectors are needed to take the next step in infrared observing.

Currently bolometers are used, which detect infrared and submillimeter waves by measuring the heat generated when photons are absorbed.

“The device we built, which we call a hot-electron nanobolometer, is potentially 100 times more sensitive than existing bolometers,” Gershenson said. “It is also faster to react to the light that hits it.”
The new device is made of titanium and niobium metals. Its about 500 nanometers long and 100 nanometers wide and was made using techniques similar to those used in computer chip manufacturing. The device operates at very cold temperatures – about 459 degrees below zero Fahrenheit, or one-tenth of one degree above absolute zero on the Kelvin scale.

Photons striking the nanodetector heat electrons in the titanium section, which is thermally isolated from the environment by superconducting niobium leads. By detecting the infinitesimal amount of heat generated in the titanium section, one can measure the light energy absorbed by the detector. The device can detect as little as a single photon of far infrared light.

“With this single detector, we have demonstrated a proof of concept,” said Gershenson. “The final goal is to build and test an array of 100 by 100 photodetectors, which is a very difficult engineering job.”

Rutgers and the Jet Propulsion Laboratory are working together to build the new infrared detector.
Gershenson expects the detector technology to be useful for exploring the early universe when satellite-based far-infrared telescopes start flying 10 to 20 years from now. “That will make our new technology useful for examining stars and star clusters at the farthest reaches of the universe,” he said.

The team’s orginal paper can be found here.
Original News Source: Rutgers State University