Universe Today

November 1, 2007April 27, 2020 by Fraser Cain

Carnival of Space

If you run a space/astronomy related blog, and would like to get more awareness, participate in the Carnival of Space. Every week, a different webmaster or blogger hosts the carnival, showcasing articles written on the topic of space. It’s a great way to get to know the community, and to help your writing reach a wider audience. If you’d like to be a host for the carnival, please send email to [email protected]

Here’s an archive of all the past Carnivals:

November 1, 2007December 26, 2015 by Fraser Cain

Supermassive Black Holes Shape Their Galaxies

Astronomers are now understanding the connection between supermassive black holes and the galaxies they inhabit better and better. In fact, it now looks like the powerful winds that blow out of these monsters can have a significant effect on the galaxies they inhabit, helping determine their growth.

In a recent study, published in the journal Nature, a group of scientists from the Rochester Institute of Technology report on their study of the rotating winds the rise up above the accretion disks surrounding supermassive black holes in distant galaxies.

With millions of times the mass of the Sun, supermassive black holes pull strongly at the material in their host galaxy. Just like water going down a drain, this material backs up into a swirling accretion disk. The material heats up, and blazes with radiation visible clear across the Universe – this is a quasar.

Astronomers from RIT and the University of Hertfordshire in England studied one quasar, PG 1700+518, located about 3 billion light-years from Earth. They were able to detect winds of gas coming off the accretion disk for the first time, both moving vertically away from the disk, but also rotating at the same speed.

This helps solve the long-standing mystery of how the accretion disk rids itself of angular momentum. It turns out, this wind needs to happen. If gas wasn’t being removed this way, material would stop falling in, and the quasar would turn off as the supermassive black hole was starved for fuel.

This wind both helps manage the growth of the black hole, but it also regulates the evolution of the galaxy. As the wind moves out into more distant regions of the galaxy, it helps collapse pockets of cold hydrogen, leading to regions of star formation.

Original Source: RIT News Release

November 1, 2007December 26, 2015 by Fraser Cain

Colliding White Dwarfs Caused a Powerful Supernova

There are a few ways that stars can go kaboom, and each variant is different enough that astronomers can figure out what kind of object detonated as a supernova. But when a bizarre explosion was detected last year, it left astronomers puzzled. Now, it looks like SN 2006gz might have been caused by two white dwarfs colliding together.

Millions of years ago, there were two regular stars in a binary system, orbiting one another. Over time, one, and then the other ran out of hydrogen fuel, bulged up as red giants, and then settled down to live out their futures as slowly cooling white dwarfs. But instead of billions of years of quiet cooling, the two stars had decaying orbits. They spiraled inward, and finally collided, detonating as supernova 2006gz.

When SN 2006gz was first discovered last year, astronomers thought they were dealing with a type Ia event. This is where a white dwarf is in a binary system with another star. Like a vampire, the white dwarf feeds on material from the companion star until it reaches 1.4 times the mass of the Sun. This magic point, called the Chandrasekhar limit, is the upper limit of mass a white dwarf can have. And when that limit is reached, the white dwarf detonates as a supernova, visible for billions of light years.

The problem is that SN 2006gz seemed to be too bright. In other words, it must have gotten more mass than the Chandrasekhar limit before detonating. It also had the strongest spectral signature of unburned carbon ever seen.

And that was the key. Mathematical models suggested that colliding white dwarfs would generate this specific signature of unburned carbon. They also suggested that an explosion should contain evidence of compressed layers of silicon, created during the explosion and then compressed during the shockwave that rebounded from the surrounding layers of carbon and oxygen – this too was seen.

Thanks to good observations, SN 2006gz was relatively easy to recognize as a collision between white dwarfs. But this event might be more common in the Universe, and astronomers will need to go back and carefully analyze supernovae on record to see if they’ve been wrongly categorized.

Original Source: CfA News Release

November 1, 2007December 26, 2015 by Mark Mortimer

Book Review: Protostars and Planets V

Fabulous theories predict a dynamic, temporal universe. Assuming a special beginning and a robust continuance, we can imagine a transformation to the state we see today. But, we’ve every reason to believe that changes continue apace. We know stars disappear in cosmically vibrant explosions. We expect stars equally arise from dust fields. This is where the book Protostars and Planets V fits in. Within its covers, the editors Bo Reipurth, David Jewitt and Klaus Keil provide a rich and rewarding collection of papers about dust, star births and other exciting dynamics.

As noted in the book’s preface, a conference about early solar system formation seemed premature in the 1970s as no planets outside our solar system were known. Nevertheless, a conference and resulting publication showed the interest in this field. Since then, regular conferences with this theme have been held. The fifth in 2005 gave rise to this book. What makes this field more and more exciting is the continual discovery of planets orbiting other stars and their kin. Hence data can corroborate or stymie conjectures and true scientific progress takes place. The collection of papers in this text shows the strength and breadth that continues to make this field exciting and advancing.

Given the physical size of this book, partly due to its nearly thousand page count, there’s no surprise that lots lies within. Suffice to say that, as with most scientific fields, there’s broad amounts of data, analysis and modeling. The real data is somewhat sparse still yet, every new discovery or detection gets readily absorbed. The papers often have pointed reviews of data and then provide conjectures about the temporal processes and dynamics that gave rise to the observations. And, it seems all were completed by very talented and learned authors; 249 in total. These authors provide a rich and varied view and perspective, many of which will undoubtedly lead to surprises and advances.

With such a bright pool of writers and noting that this book results from a conference, the reader must be prepared to wade through without assistance. Equations are the norm rather than the exception. Given the dynamic nature of the subject, base physics involving density, temperature, pressure and photons are thrown about with the freedom that comes from every day usage. Yet, there’s no appearance of showmanship. Rather, the reports in this book demonstrate an eagerness and sincerity in the belief that the offerings are making a significant contribution to science.

Nevertheless, this is the proceedings from the fifth conference and within are allusions to a sixth. Thus, the reader needs to realize that the content represents ongoing work rather than a penultimate conclusion. Presumably we will continue to build and utilize better observatories and more capable computers. Hence, this book is an excellent snapshot of activity in 2005. But, there were referrals to new observations not yet fully analyzed but likely to skew the statistics. In consequence, the book’s contents would be great for a reader who wants to catch-up on this particular topic as there is no conclusion. Further, with authors’ names and indications of funding sources, a reader has got a ready way to follow-up. And, they could get help directing their own work, contemplate choices about how they could aid in the research or simply keep up to date.

Given the narrowness of the topic and the complexity of the presentation, the general reader or hobbyist will have a challenge cruising through the pages. But, there’s lots to discover for those so desiring. There’s dust columns that might indicate the size of dust fields, metrics that indicate if a planet is in the habitable zone and models that show the likelihood of accretion or disintegration. Just be prepared to have to wade through thick details full of charts, acronyms and specialist lingo. Much can be discerned, but the average reader will have to work at it; it’s not offered up on a plate.

The continual fly-by of comets shows everyone on Earth that our universe is rich in dynamics. Those with access to observatories and their resulting images know that the dynamism extends throughout space. The editors Bo Reipurth, David Jewitt and Klaus Keil provide papers in their book entitled Protostars and Planets V that show how such dynamism could lead to new stars out of a field of dust. Hence that wonderful expression, “We’re all made from star dust” is all the more apt!

November 1, 2007December 26, 2015 by Fraser Cain

Carnival of Space #27 – and an Announcement

I’m happy once again to be the host of the Carnival of Space, here at Universe Today. I also wanted to announce that I’m going to be taking over the reins of the carnival from the founder, Henry Cate, who’s getting a little spread too thin with everything he’s working on. A big thanks to Henry for putting the time to get things to this point, and I hope I’m able to live up to the high standards he created. If you have any questions, just drop me an email at [email protected].

Now, onto the carnival.

Space Files writes about a little known amateur-built satellite bound for Mars.

Have you ever wondered what the Milky Way would look like if you could get outside it? astropixie takes us on a tour out of the galaxy, step by step.

Maybe there isn’t any such thing as dark matter. Centauri Dreams looks at an alternative theory to Newtonian gravity that might just solve the problem.

Surfin English shows the tricks, tools and techniques you need to photograph the planets.

As the media focuses its attention on the troubles with torn solar arrays and stuck joints affecting the latest shuttle/ISS mission, Stuart Atkinson, is frustrated by the lack of attention paid to a very special and historic meeting that took place at the start of the mission.

Once it was thought that moons could not exist within the Roche Limit. Now there is evidence of moons and possibly other massive objects. Since Saturn’s Rings contain conditions similar to the Solar System’s formation, they may shed light on how our Earth was formed. From A Babe in the Universe.

And finally, from my own Universe Today, I humbly offer up this article about the search for the origins of the Tunguska impactor.

October 31, 2007January 24, 2021 by Fraser Cain

Astrosphere for October 31st, 2007

Happy Halloween everyone. First up, enjoy a triple view of Comet Holmes, captured by ngc3314.

Of course, Halloween is an excuse to write spooky flavoured press releases. Here’s one from NASA’s Cassini mission about the spooky sounds of the Saturnian system. And this chilling tale of a meteorite… IT Came From Vesta. Astronomy Picture of the Day focuses on the “Ghost Head Nebula“. Cosmic Log’s Alan Boyle looks at the science of spooks. And finally, Phil Plait has a terrifying image of, of… well, you’ll just have to see for yourself.

Thomas Marquart from Apparent Brightness suggests a trick you can use to pare down your RSS feeds to just get the ones you want. I actually do this to just focus on space-related news.

Have you noticed a bright star in the mornings? That’s not a star, that’s Venus.

Centauri Dreams reconsiders Gliese 581. It’s looking less and less Earthlike every day.

October 31, 2007December 26, 2015 by Fraser Cain

Three New Jupiter-Sized Planets Discovered

You know the science of planet hunting is getting mainstream when there’s very little fanfare for the discovery of 3 new extrasolar planets with the size of Jupiter. 3 new planets people! They’re named WASP-3, WASP-4, WASP-5, and were discovered by a European team of astronomers using observatories in South Africa and the Canary Islands.

The new planets were discovered using the SuperWASP instruments. These are high speed cameras affixed to two telescopes: SuperWASP-North at Roque de los Muchachos Observatory on the island of La Palma in the Canaries and SuperWASP-South at the South African Astronomical Observatory, South Africa. Both instruments are equipped with a detailed CCD camera array capable of monitoring up to 400,000 stars every minute.

They’re watching to see if any of those stars vary in brightness. If a star does get brighter and dimmer over a regular period, the astronomers can then determine if a planet is passing in front – an event known as a transit (or eclipse). Just by measuring the dimming, astronomers can then determine the size of the planet, and even some of its chemical constituents.

With this latest discovery, the three new planets all contain roughly the mass of Jupiter, but orbit much closer into their parent stars. They complete an orbit every 2 two days.

According to one of the discoverers, Dr Don Pollacco of Queenâ€™s Astrophysics Research Centre, “these are among the shortest orbital periods yet discovered. Being so close to their star, the surface temperatures of the planets will be more than 2000 C, so it is unlikely that life as we know it could survive there. However, the finding of Jupiter-mass planets around other stars supports the idea that there are also many Earth-sized planets waiting to be discovered as the technology employed by astronomers improves.â€?

Even a relatively tiny planet the size of the Earth should visibly dim the light from a star as it passes in front. This is an exciting technique that should just get better and better over time.

Original Source: University of St. Andrews News Release

October 31, 2007December 26, 2015 by Fraser Cain

Detailed Images of Comet Holmes

Late last week, the normally dim Comet 17P/Holmes suddenly blazed into view, increasing in brightness by a factor of a million. Before the eruption you needed a large telescope to see it, and now you can make it out with the unaided eye – even in the light-polluted city skies.

There are now many amateur and professional astronomers turning their gaze towards the newly brightened comet.

Eric Allen has been capturing images for several days, and stitched them together into an animation that shows the expanding coma. Even cooler, he compares it to Jupiter visually, so you can see just how big and bright it has gotten.

UK astronomers tuned in with the powerful Isaac Newton Telescope in La Palma, showing the fuzzy coma. They also tucked in an image of the Earth in the bottom corner, for scale.

Astronomers from the University of Montreal captured this image that seems to show that the comet has an actual tail.

Probably the best image I’ve seen was captured by Mario Motta from the Amateur Telescope Makers in Boston. His image shows what clearly looks like a jet, blasting off one side of the comet.

Still want more images? Space Weather has this enormous photo gallery of images of Comet 17P/Holmes.

Over the next few days/weeks, I’m sure some even bigger telescopes will be joining the fray, so stay tuned.

October 31, 2007December 26, 2015 by Fraser Cain

Better View of the Damaged Panel

With all that fancy camera equipment, the NASA astronauts took more detailed images of the damaged solar panels on the International Space Station. These are the images NASA engineers will use to figure out what kind of risk the panel faces if it’s fully deployed, and what kinds of repairs could be done to minimize the damage. Oh, and the next spacewalk has been delayed to Friday.

Because of the damaged panel, managers at NASA decided to change up their plans for the next few days. Instead of their originally scheduled spacewalk, to demonstrate tile repair techniques, the astronauts will now be focusing on damage assessment and repair.

They’ve got to have another look at the malfunctioning rotary joint on the right-hand side of the station. The joint is currently parked because the mechanism was vibrating too much, and consuming energy. When astronaut Daniel Tani looked inside, he found evidence that the mechanism was grinding together, shedding tiny metal shavings. During the latest spacewalk, the astronauts looked at the right-hand side and found that it was working fine.

The tear in the solar array happened during the latest spacewalk on Tuesday. The astronauts had just completed the redeployment of the solar array to its new home, and were extending the panels. A portion of the panels were invisible in the glare of the Sun, so the astronauts didn’t notice its damage until it was too late.

The 80 cm tear in the array was probably caused when a guide wire snagged one of the hinges that allow the panels to fold up tight. As the panel was extended, one flap hooked onto this guide wire and tore along the fold.

NASA is now in a bit of a bind. Although they’re generating power now, they’ll work best when fully extended. There are also structural problems with having the array not fully extended. For the time being, both rotary joints have been locked shut, protecting the panels, but reducing the station’s ability to generate power.

Original Source: NASA News Release

October 30, 2007December 26, 2015 by Fraser Cain

Hubble Sees Beautiful Carnage

Ahh, another beautiful photograph captured by the Hubble Space Telescope. This time we’re looking at two big, beautiful spiral galaxies… tearing each other apart. The large, face-on spiral is NGC 3808, while its dueling partner is the smaller, edge-on NGC 3808A. And between the two is a long today tail of stars, gas and dust, transferring from one to the other.

The two galaxies are collectively known as Arp 87; just one of the hundreds of interacting galaxies seen by astronomers. It was cataloged by the famous Halton Arp in the 1960’s, who maintained his Atlas of Peculiar Galaxies. And this collision is plenty peculiar, thanks to Hubble’s optics and resolution of fine details.

A stream of gas, stars and dust is flowing from NGC 3808 to its companion, enveloping it in a starry embrace. Because the NGC 3808A is seen nearly edge-on, you can make out the twisting trail of stars wrapping around it. Both galaxies have been distorted by their gravitational interaction.

When galaxies interact, stars are born. And this is the case for Arp 87. The colour of the stars and the intensity of heated interstellar dust show that both galaxies are undergoing furious rates of star formation.

Original Source: Hubble News Release