Featured Archives

March 15, 2016March 18, 2016 by Evan Gough

90 Years Ago Goddard’s Liquid-Fuelled Rocket Launched Spaceflight

Dr. Robert H. Goddard and a liquid oxygen-gasoline rocket in the frame from which it was fired on March 16, 1926, at Auburn, Massachusetts. Image: NASA/Clark University Robert H. Goddard Archive

The invention of the rocket changed space science forever. The Universe could only be inspected from the surface of the Earth, with all that atmosphere in the way, until rockets were invented. And as far as the modern age of rocketry goes, it all started 90 years ago with Robert Goddard’s liquid-fuelled rocket.

Goddard was a dreamer. He envisioned rocket-powered spacecraft plying the solar system. Obviously, he passed away before interplanetary travel materialized, but his work on rocketry certainly laid the groundwork for that eventual achievement. The Goddard Space Flight Center is named after him, and it’s doubtful that any engineering or technology student in the world doesn’t know who he is.

Goddard’s first liquid-fuelled rocket was modest by today’s standards, of course. But he had to solve several technical challenges to achieve it, and his ability to solve these challenges led to not only this first flight, but to a total of 34 rocket flights in 15 years, from 1926 to 1941. His rockets reached the altitude of 2.6 km (1.6 miles) and speeds of 885 km/h (550 mph.) He also patented 214 inventions.

Goddard is considered the father of modern rocket science, but he is actually one of three men who are considered the main contributors to modern rocketry. Russian Konstantin Tsiolkovsky (1858-1935) and German Hermann Oberth (1894-1989) are the other founding fathers of modern rocketry.

Goddard didn’t invent rocketry, of course. The Chinese used rockets as far back as the 13th century, and rockets made appearances throughout history as weapons and fireworks. But Goddard’s success at liquid-fuelled rocketry, and the capabilities that came with it, is when rocketry really got off the ground. (Sorry.)

Nowadays, Goddard is understood to be a driven and highly-intelligent person, the type of person who is responsible for advancing science and technology. But back in his time, before he had successful flights, he and his ideas were ridiculed. Check out this criticism from the New York Times, January 13th, 1920:

“That Professor Goddard, with his ‘chair’ in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react — to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.”

Stinging words, to be sure, but people who know anything about the history of science are familiar with this kind of condemnation of brilliant people, coming from those who lack vision.

Now of course, we have huge rockets. Great thundering beasts that lift enormous loads out of Earth’s gravity well. And we’re so accustomed to rocket launches now that they barely make news. But I always get a kick out of imagining what people like Goddard would feel if they were able to view a launch of one of today’s behemoths, like the Ariane 5. I’m sure his chest would swelled with pride, and he would be amazed at what people have accomplished.

But his vindication wouldn’t just come from the huge leaps we’ve made in rocket technology, and the huge rockets we now routinely launch. It would also come from this retraction, delivered decades too late but with class, by the New York Times, on July 17 1969, the day after Apollo 11 launched:

Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.

March 15, 2016March 18, 2016 by Evan Gough

Eat Your Heart Out Pluto

Sublimation of methane ice (shown in purple in the right inset) to methane gas may be eroding the cliffs of Piri Rupes. This process is creating what looks like a bite mark in Pluto's surface, and leaving the Piri Planitia in their wake. (All names for the geographical features on Pluto are still informal.) Image: NASA/JHUAPL/SwRI

Images from the New Horizons spacecraft show a bite-mark shaped feature on the surface of Pluto. Scientists think that the feature is caused by the sublimation of methane ice, causing cliffs to erode and leaving a flat plain in their place. The images were captured just prior to New Horizon’s closest approach to Pluto on July 14th, 2015.

In the image above, which is of Pluto’s western hemisphere, three main features are shown. The first is Vega Terra, which as a raised plateau area. The second is the Piri Planitia, which is a flatter and lower area of plains. Piri Planitia shows an absence of craters, meaning it is geologically younger. Dividing Terra and Planitia are the Piri Rupes, the cliffs which have the bite-mark shaped feature that caught the interest of scientist.

The colored image on the right shows methane-rich areas in purple. Scientists think that as the methane ice of Piri Rupes is sublimated away into the atmosphere, the cliffs are removed and the flat plains of Piri Planitia take their place. The image also shows some methane mesas which have not sublimated away yet.

This image shows the location on Pluto where the sublimation of methane is leaving a bite-mark shape, and changing the surface of Pluto. Image: NASA/JHUAPL/SwRI

New Horizons’ data also shows that Piri Planitia has a higher content of water ice, which is shown in blue. Because of the frigid temperature on Pluto, it’s thought that this water ice is like bedrock. It is immobile, and as the methane ice is sublimated away, the water ice bedrock of Piri Planitia is left exposed.

Prior to New Horizons’ arrival at Pluto, it was generally thought that not much was happening at Pluto. But as these images show, and as New Horizons keeps proving, Pluto is far from an inactive place, and there’s a lot to hold the interest of planetary scientists.

March 14, 2016March 18, 2016 by Evan Gough

The Milky Way Galaxy’s Dark Halo Of Star Formation

Dark matter is invisible. Based on the effect of gravitational lensing, a ring of dark matter has been inferred in this image of a galaxy cluster (CL0024+17) and has been represented in blue. Image: NASA/ESA.

Dark Matter is rightly called one of the greatest mysteries in the Universe. In fact, so mysterious is it, that we here in the opulent sky-scraper offices of Universe Today often joke that it should be called “Dark Mystery.” But that sounds like a cheesy History Channel show, and here at Universe Today we don’t like cheesy, so Dark Matter it remains.

Though we still don’t know what exactly Dark Matter is, we keep learning more about how it interacts with the rest of the Universe, and nibbling around at the edges of what it might be. But before we get into the latest news about Dark Matter, it’s worth stepping back a bit to remind ourselves of what is known about Dark Matter.

Evidence from cosmology shows that about 25% of the mass of the Universe is Dark Matter, also known as non-baryonic matter. Baryonic matter is ‘normal’ matter, which we are all familiar with. It’s made up of protons and neutrons, and it’s the matter that we interact with every day.

Cosmologists can’t see the 25% of matter that is Dark Matter, because it doesn’t interact with light. But they can see the effect it has on the large scale structure of the Universe, on the cosmic microwave background, and in the phenomenon of gravitational lensing. So they know it’s there.

Large galaxies like our own Milky Way are surrounded by what is called a halo of Dark Matter. These huge haloes are in turn surrounded by smaller sub-haloes of Dark Matter. These sub-haloes have enough gravitational force to form dwarf galaxies, like the Milky Way’s own Sagittarius and Canis Major dwarf galaxies. Then, these dwarf galaxies themselves have their own Dark Matter haloes, which at this scale are now much too small to contain gas or stars. Called dark satellites, these smaller haloes are of course invisible to telescopes, but theory states they should be there.

But proving that these dark satellites are even there requires some evidence of the effect they have on their host galaxies.

Now, thanks to Laura Sales, who is an assistant professor at the University of California, Riverside’s, Department of Physics and Astronomy, and her collaborators at the Kapteyn Astronomical Institute in the Netherlands, Tjitske Starkenberg and Amina Helmi, there is more evidence that these dark satellites are indeed there.

In their paper “Dark influences II: gas and star formation in minor mergers of dwarf galaxies with dark satellites,” from November 2015, they provide an analysis of theory-based computer simulations of the interaction between a dwarf galaxy and a dark satellite.

Their paper shows that when a dark satellite is at its closest point to a dwarf galaxy, the satellite’s gravitational influence compresses the gas in the dwarf. This causes a sustained period of star formation, called a starburst, that can last for billions of years.

NGC 5253 is one of the nearest of the known Blue Compact Dwarf (BCD) galaxies, and is located at a distance of about 12 million light-years from Earth in the southern constellation of Centaurus. It is experiencing a starburst of hot, young stars, which could be caused by dark satellites. Image: NASA/ESA/Hubble.

Their modelling suggests that dwarf galaxies should be exhibiting a higher rate of star formation than would otherwise be expected. And observation of dwarf galaxies reveals that that is indeed the case. Their modelling also suggests that when a dark satellite and a dwarf galaxy interact, the shape of the dwarf galaxy should change. And again, this is born out by the observation of isolated spheroidal dwarf galaxies, whose origin has so far been a mystery.

The exact nature of Dark Matter is still a mystery, and will probably remain a mystery for quite some time. But studies like this keep shining more light on Dark Matter, and I encourage readers who want more detail to read it.

March 14, 2016February 23, 2017 by Fraser Cain

What are the Different Kinds of Supernovae?

There are a few places in the Universe that defy comprehension. And supernovae have got to be the most extreme places you can imagine. We’re talking about a star with potentially dozens of times the size and mass of our own Sun that violently dies in a faction of a second.

Faster than it take me to say the word supernova, a complete star collapses in on itself, creating a black hole, forming the denser elements in the Universe, and then exploding outward with the energy of millions or even billions of stars.

But not in all cases. In fact, supernovae come in different flavours, starting from different kinds of stars, ending up with different kinds of explosions, and producing different kinds of remnants.

There are two main types of supernovae, the Type I and the Type II. I know this sounds a little counter intuitive, but let’s start with the Type II first.

These are the supernovae produced when massive stars die. We’ve done a whole show about that process, so if you want to watch it now, you can click here.

Our eyes would never see the Crab Nebula as this Hubble image shows it. Image credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)

But here’s the shorter version.

Stars, as you know, convert hydrogen into fusion at their core. This reaction releases energy in the form of photons, and this light pressure pushes against the force of gravity trying to pull the star in on itself.

Our Sun, doesn’t have the mass to support fusion reactions with elements beyond hydrogen or helium. So once all the helium is used up, the fusion reactions stop and the Sun becomes a white dwarf and starts cooling down.

But if you have a star with 8-25 times the mass of the Sun, it can fuse heavier elements at its core. When it runs out of hydrogen, it switches to helium, and then carbon, neon, etc, all the way up the periodic table of elements. When it reaches iron, however, the fusion reaction takes more energy than it produces.

The outer layers of the star collapses inward in a fraction of a second, and then detonates as a Type II supernova. You’re left with an incredibly dense neutron star as a remnant.

But if the original star had more than about 25 times the mass of the Sun, the same core collapse happens. But the force of the material falling inward collapses the core into a black hole.

Extremely massive stars with more than 100 times the mass of the Sun just explode without a trace. In fact, shortly after the Big Bang, there were stars with hundreds, and maybe even thousands of times the mass of the Sun made of pure hydrogen and helium. These monsters would have lived very short lives, detonating with an incomprehensible amount of energy.

Artist's impression of a supernova — Artist’s impression of a supernova

Those are Type II. Type I are a little rarer, and are created when you have a very strange binary star situation.

One star in the pair is a white dwarf, the long dead remnant of a main sequence star like our Sun. The companion can be any other type of star, like a red giant, main sequence star, or even another white dwarf.

What matters is that they’re close enough that the white dwarf can steal matter from its partner, and build it up like a smothering blanket of potential explosiveness. When the stolen amount reaches 1.4 times the mass of the Sun, the white dwarf explodes as a supernova and completely vaporizes.

In a Type Ia supernova, a white dwarf (left) draws matter from a companion star until its mass hits a limit which leads to collapse and then explosion. Credit: NASA

Because of this 1.4 ratio, astronomers use Type Ia supernovae as “standard candles” to measure distances in the Universe. Since they know how much energy it detonated with, astronomers can calculate the distance to the explosion.

There are probably other, even more rare events that can trigger supernovae, and even more powerful hypernovae and gamma ray bursts. These probably involve collisions between stars, white dwarfs and even neutron stars.

As you’ve probably heard, physicists use particle accelerators to create more massive elements on the Periodic Table. Elements like ununseptium and ununtrium. It takes tremendous energy to create these elements in the first place, and they only last for a fraction of a second.

But in supernovae, these elements would be created, and many others. And we know there are no stable elements further up the periodic table because they’re not here today. A supernova is a far better matter cruncher than any particle accelerator we could ever imagine.

Next time you hear a story about a supernova, listen carefully for what kind of supernova it was: Type I or Type II. How much mass did the star have? That’ll help your imagination wrap your brain around this amazing event.

March 14, 2016March 18, 2016 by Bob King

Stunning Conjunction of Mars and Beta Scorpii This Week

Planets can sneak up on you. Especially the ones that don’t rise till you’re in bed. Take Mars for instance. It’s been ambling east along the morning zodiac all winter long; today it enters Scorpius, rising around 1:30 a.m. Not two days later, the planet will have a spectacularly close conjunction with Beta Scorpii, the topmost star in the scorpion’s head.

This close up of the head of Scorpius shows Mars' progress over the next three mornings. Positions are shown for 5:30 a.m. CDT. Diagram: Bob King, source: Stellarium — This close up of the head of Scorpius shows Mars’ progress over the next three mornings. Positions are shown for 5:30 a.m. CDT. Diagram: Bob King, source: Stellarium

Also known as Graffias, Beta shines at magnitude +2.6 next to the fiery, zero-magnitude Mars. With their striking color contrast, the two would make a superb ring setting: a tiny diamond nestled next to a plump garnet. They’ll be together for several mornings, their separation changing each day: 15 arc minutes on Tuesday (1/2 the diameter of the Full Moon); 9 arc minutes when closest on Wednesday and back out to 23 minutes on Thursday.

In a telescope, diminutive Mars pairs up with gorgeous Graffias. Diagram: Bob King , source: Stellarium — In a telescope, diminutive Mars pairs up with gorgeous Graffias. North is up and left. Beta-1, the brighter of the two, has an additional 1oth magnitude companion half an arc-second away, while Beta-2 is also double with a faint companion 1/10th of arc second distant. That’s not all. Beta-1 is an exceedingly close binary — making Graffias at least a five-star system! Diagram: Bob King , source: Stellarium

It’s a gas to see two celestial objects approach so closely, but this conjunction offers a rare treat. Did you know that Beta is one of the finest double stars in the sky? It has a fifth magnitude companion 14 arc seconds northeast of the primary. Any telescope will split this jewel and show Mars in the same field of view at both high and low magnifications. That’s just so cool — I sure hope you’ll get to see them.

Mars, in gibbous phase, is still small but starting to show its larger surface features in modest-sized telescopes. This photo, taken on March 13th, shows the prominent Mare Acidalium in the planet's northern hemisphere (top) and a hint of the north polar cap. Sinus Aurorae and Mare Erythraeum dominate the south. Credit: Anthony Wesley — Mars, in gibbous phase, is still small but its larger surface features are now visible in modest-sized telescopes. This photo, taken on March 13th, shows Mare Acidalium in the planet’s northern hemisphere (top) and a hint of the north polar cap. Sinus Aurorae and Mare Erythraeum dominate the south. Click for a Mars map. Credit: Anthony Wesley

Mars now measures 10 arc seconds in diameter, small for sure, but big enough to see the larger dark markings and a hint of the north polar cap. The planet is heading for opposition on May 22nd, when it will shine at magnitude -2.0 (brighter than Sirius) with a disk 18.4 arc seconds across, its biggest and closest since 2005.

Let this week’s lovely conjunction serve as a warm-up to the forthcoming season of Mars.

March 14, 2016March 15, 2016 by Ken Kremer

ExoMars Spacecraft Launches to Red Planet Searching for Signs of Life

ExoMars 2016 lifted off on a Proton-M rocket from Baikonur, Kazakhstan at 09:31 GMT on 14 March 2016. Copyright ESA–Stephane Corvaja, 2016

The joint European/Russian ExoMars spacecraft successfully launched early this morning from the Baikonur Cosmodrome in Kazakhstan atop a Proton-M rocket at 5:31:42 a.m. EDT (0931:42 GMT), Monday, March 14, with the goal of searching for signs of life on the Red Planet.

After settling into orbit around Mars, it’s instruments will scan for minute signatures of methane gas that could possibly be an indication of life or of nonbiologic geologic processes ongoing today.

The spacecraft is currently circling in a temporary and preliminary parking orbit around Earth following liftoff of the 191-foot-tall (58-meter) Russian-built rocket under overcast skies – awaiting a critical final engine burn placing the probe on an interplanetary trajectory to Mars.

The 9,550-pound (4,332-kilogram) ExoMars 2016 spacecraft continued soaring to orbit after nominal firings of the Proton’s second and third stages and jettisoning of the payload fairing halves protecting the vehicle during ascent through Earth’s atmosphere.

A total of four more burns from the Breeze-M upper stage are required to boost ExoMars higher and propel it outwards on its seven-month-long journey to the Red Planet.

So the excitement and nail biting is not over yet and continues to this moment. The final successful outcome of today’s mission cannot be declared until more than 10 hours after liftoff – after the last firing of the Breeze-M upper stage sets the probe on course for Mars and escaping the tug of Earth’s gravity.

The first three Breeze-M fourth stage burns have now been completed as of about 9:40 am EST, according to ESA mission control on Darmstadt, Germany.

The fourth and final ignition of the Breeze-M upper stage and spacecraft separation is slated for after 3 p.m. EDT today, March 14, 2016.

The first acquisition of signal from the spacecraft is expected later at about 5:21:29 p.m. EST (21:29 GMT).

Artists concept of ExoMars spacecraft separation from Breeze fourth stage. Credit: ESA

The ExoMars 2016 mission is comprised of a joined pair of European-built spacecraft consisting of the Trace Gas Orbiter (TGO) plus the Schiaparelli entry, descent and landing demonstrator module, built and funded by the European Space Agency (ESA).

The cooperative mission includes significant participation from the Russian space agency Roscosmos who provided the Proton-M launcher, part of the science instrument package, the surface platform and ground station support.

The launch was carried live courtesy of a European Space Agency (ESA) webcast:

http://www.esa.int/Our_Activities/Space_Science/ExoMars/Watch_ExoMars_launch

ESA is continuing live streaming of the launch events throughout the day as burns continue and events unfold lead up to the critical final burn of the Breeze-M upper stage

The ExoMars 2016 TGO orbiter is equipped with a payload of four science instruments supplied by European and Russian scientists. It will investigate the source and precisely measure the quantity of the methane and other trace gases, present at levels of one percent or far less.

On Earth methane can be produced by biology, volcanoes, natural gas and hydrothermal activity. TGO will investigate what makes it on Mars and follow up on measurements from NASA’s Curiosity rover and other space based assets and telescopes.

Martian methane has a lifetime of about 400 years, until it is destroyed by solar UV & mixed by atmosphere, says Jorge Vago, ESA ExoMars 2016 principal scientist.

The 2016 lander will carry an international suite of science instruments and test European entry, descent and landing (EDL) technologies for the 2nd ExoMars mission in 2018.

The battery powered lander is expected to operate for perhaps four and up to eight days until the battery is depleted.

The 2018 ExoMars mission will deliver an advanced rover to the Red Planet’s surface.

It is equipped with the first ever deep driller that can collect samples to depths of 2 meters (seven feet) where the environment is shielded from the harsh conditions on the surface – namely the constant bombardment of cosmic radiation and the presence of strong oxidants like perchlorates that can destroy organic molecules.

ExoMars was originally a joint NASA/ESA project.

But thanks to hefty cuts to NASA’s budget by Washington DC politicians, NASA was forced to terminate the agencies involvement after several years of extremely detailed work and withdraw from participation as a full partner in the exciting ExoMars missions.

NASA is still providing the critical MOMA science instrument that will search for organic molecules.

Thereafter Russia agreed to take NASA’s place and provide the much needed funding and rockets for the pair of launches in March 2016 and May 2018.

TGO will also help search for safe landing sites for the ExoMars 2018 lander and serve as the all important data communication relay station sending signals and science from the rover and surface science platform back to Earth.

ExoMars 2016 is Europe’s most advanced mission to Mars and joins Europe’s still operating Mars Express Orbiter (MEX), which arrived back in 2004, as well as a fleet of NASA and Indian probes.

ExoMars 2016: Trace Gas Orbiter and Schiaparelli. Credit: ESA/ATG medialab — ExoMars 2016: Trace Gas Orbiter and Schiaparelli. Credit:
ESA/ATG medialab

The Trace Gas Orbiter (TGO) and Schiaparelli lander arrive at Mars on October 19, 2016.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Proton rocket and ExoMars 2016 spacecraft stand vertical at the launch pad at the Baikonur cosmodrome, Kazakhstan Copyright: ESA - B. Bethge — Proton rocket and ExoMars 2016 spacecraft stand vertical at the launch pad at the Baikonur cosmodrome, Kazakhstan
Copyright: ESA – B. Bethge

March 13, 2016March 13, 2016 by Ken Kremer

Countdown Begins for Blastoff of ExoMars 2016 Spacecraft on March 14 – Watch Live

Proton rocket and ExoMars 2016 spacecraft rolled out to launch pad at the Baikonur cosmodrome, Kazakhstan Copyright: ESA - B. Bethge

The countdown has begun for blastoff of the ambitious European/Russian ExoMars 2016 spacecraft from the Baikonur Cosmodrome in Kazakhstan on March 14. Its goal is to search for minute signatures of methane gas that could possibly be an indication of life or of nonbiologic geologic processes ongoing today.

Final launch preparations are now in progress. Liftoff of the powerful Russian Proton booster from Baikonur carrying the ExoMars spacecraft is slated for 5:31:42 a.m. EDT (0931:42 GMT), Monday morning, March 14.

You can watch the launch live courtesy of a European Space Agency (ESA) webcast:

http://www.esa.int/Our_Activities/Space_Science/ExoMars/Watch_ExoMars_launch

The prelaunch play by play begins with live streaming at 4:30 a.m. EDT (08:30 GMT).

The first acquisition of signal from the spacecrft is expected at 21:29 GMT

As launch and post launch events unfold leading to spacecraft separation, ESA plans additional live streaming events at 7:00 a.m. EDT (11:00 GMT) and 5:10 p.m. (21:10 GMT)

Spacecraft separation from the Breeze upper stage is expected at about 10 hours, 41 minutes.

The ExoMars 2016 mission is comprised of a pair of European spacecraft named the Trace Gas Orbiter (TGO) and the Schiaparelli entry, descent and landing demonstration lander, built and funded by the European Space Agency (ESA).

Russian is providing the Proton booster and part of the science instrument package.

“The main objectives of this mission are to search for evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes and to test key technologies in preparation for ESA’s contribution to subsequent missions to Mars,” says ESA.

ExoMars is Earth’s lone mission to the Red Planet following the two year postponement of NASA’s InSight lander from 2016 to 2018 to allow time to fix a defective French-built seismometer.

ESA reported late today , March 13, that at T-minus 12 hours the Trace Gas Orbiter has been successfully switch on, a telemetry link was established and the spacecrft battery charging has been completed.

The Proton rocket with the encapsulated spacecraft bolted atop were rolled out to the Baikonur launch pad on Friday, March 11 and the launcher was raised into the vertical position.

ESA mission controller then completed a full launch dress rehearsal on Saturday, March 12.

The ExoMars 2016 spacecraft composite, comprised of the Trace Gas Orbiter and Schiaparelli, seen during the encapsulation within the launcher fairing at the Baikonur cosmodrome in Kazakhstan. Launch to Mars is slated for March 14, 2016. Copyright: ESA - B. Bethge — The ExoMars 2016 spacecraft composite, comprised of the Trace Gas Orbiter and Schiaparelli, seen during the encapsulation within the launcher fairing at the Baikonur cosmodrome in Kazakhstan. Launch to Mars is slated for March 14, 2016. Copyright: ESA – B. Bethge

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

March 13, 2016March 18, 2016 by Bob King

18 Billion Solar Mass Black Hole Rotates At 1/3 Speed Of Light

Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope. They are sources of neutrinos and cosmic rays. Credits: M. Weiss/CfA

Way up in the constellation Cancer there’s a 14th magnitude speck of light you can claim in a 10-inch or larger telescope. If you saw it, you might sniff at something so insignificant, yet it represents the final farewell of chewed up stars as their remains whirl down the throat of an 18 billion solar mass black hole, one of the most massive known in the universe.

Astronomers know the object as OJ 287, a quasar that lies 3.5 billion light years from Earth. Quasars or quasi-stellar objects light up the centers of many remote galaxies. If we could pull up for a closer look, we’d see a brilliant, flattened accretion disk composed of heated star-stuff spinning about the central black hole at extreme speeds.

An illustration of the binary black hole system in OJ287. The predictions of the model are verified by observations. Credit: University of Turku — An illustration of the binary black hole system, OJ 287, showing the massive black hole surrounded by an accretion disk. A second, smaller black hole is believed to orbit the larger. When it intersects the larger’s disk coming and going, astronomers see a pair of bright flares. The predictions of the model are verified by observations. Credit: University of Turku

As matter gets sucked down the hole, jets of hot plasma and energetic light shoot out perpendicular to the disk. And if we’re so privileged that one of those jet happens to point directly at us, we call the quasar a “blazar”. Variability of the light streaming from the heart of a blazar is so constant, the object practically flickers.

Long exposures made with the Hubble Space Telescope showing brilliant quasars flaring in the hearts of six distant galaxies. Credit: NASA/ESA

A recent observational campaign involving more than two dozen optical telescopes and NASA’s space based SWIFT X-ray telescope allowed a team of astronomers to measure very accurately the rotational rate the black hole powering OJ 287 at one third the maximum spin rate — about 56,000 miles per second (90,000 kps) — allowed in General Relativity A careful analysis of these observations show that OJ 287 has produced close-to-periodic optical outbursts at intervals of approximately 12 years dating back to around 1891. A close inspection of newer data sets reveals the presence of double-peaks in these outbursts.

Illustration of a gradually precessing orbit similar to the precessing orbit of the smaller smaller black hole orbiting the larger in OJ 287. Credit: Willow W / Wikipedia

To explain the blazar’s behavior, Prof. Mauri Valtonen of the University of Turku (Finland) and colleagues developed a model that beautifully explains the data if the quasar OJ 287 harbors not one buy two unequal mass black holes — an 18 billion mass one orbited by a smaller black hole.

OJ 287 is visible due to the streaming of matter present in the accretion disk onto the largest black hole. The smaller black hole passes through the larger’s the accretion disk during its orbit, causing the disk material to briefly heat up to very high temperatures. This heated material flows out from both sides of the accretion disk and radiates strongly for weeks, causing the double peak in brightness.

The orbit of the smaller black hole also precesses similar to how Mercury’s orbit precesses. This changes when and where the smaller black hole passes through the accretion disk. After carefully observing eight outbursts of the black hole, the team was able to determine not only the black holes’ masses but also the precession rate of the orbit. Based on Valtonen’s model, the team predicted a flare in late November 2015, and it happened right on schedule.

OJ 287 has been fluctuating around 13.5-140 magnitude lately. You can spot in a 10-inch or larger scope in Cancer not far from the Beehive Cluster. Click the image for a detailed AAVSO finder chart. Diagram: Bob King, source: Stellarium — OJ 287 has been fluctuating around 13.5-140 magnitude lately. You can spot it in a 10-inch or larger scope in Cancer not far from the Beehive Cluster. Click the image for a detailed AAVSO finder chart. Diagram: Bob King, source: Stellarium

The timing of this bright outburst allowed Valtonen and his co-workers to directly measure the rotation rate of the more massive black hole to be nearly 1/3 the speed of light. I’ve checked around and as far as I can tell, this would make it the fastest spinning object we know of in the universe. Getting dizzy yet?

March 12, 2016March 12, 2016 by Ken Kremer

NASA Test Fires SLS Flight Engine Destined to Launch Astronauts Back to the Moon

NASA engineers conduct a successful test firing of RS-25 rocket engine No. 2059 on the A-1 Test Stand at NASA’s Stennis Space Center in Bay St. Louis, Mississippi. The hot fire marks the first test of an RS-25 flight engine for NASA’s new Space Launch System vehicle. Credits: NASA/SSC

NASA engineers conduct a successfully test firing of RS-25 rocket engine No. 2059 on the A-1 Test Stand at NASA’s Stennis Space Center in Bay St. Louis, Mississippi. The hot fire marks the first test of an RS-25 flight engine for NASA’s new Space Launch System vehicle. Credits: NASA/SSC — NASA engineers conduct a successful test firing of RS-25 rocket engine No. 2059 on the A-1 Test Stand at NASA’s Stennis Space Center in Bay St. Louis, Mississippi. The hot fire marks the first test of an RS-25 flight engine for NASA’s new Space Launch System vehicle. Credits: NASA/SSC

NASA engineers have successfully test fired the first flight engine destined to power the agency’s mammoth new SLS rocket that will launch American astronauts back to the Moon and deep space for the first time in nearly five decades.

The flight proven RS-25 powerplant engine previously flew as one of three main engines that successfully rocketed NASA’s space shuttle orbiters to space during the three decade long Space Shuttle era that ended in 2011. Continue reading “NASA Test Fires SLS Flight Engine Destined to Launch Astronauts Back to the Moon”

March 11, 2016March 18, 2016 by Evan Gough

Cassini Watches Star Through Enceladus’ Plume

When the Cassini probe first saw the plumes coming from Saturn’s moon Enceladus, it was a surprise. When it dipped through the plumes, some questions about the basic nature of the phenomenon were answered. But there are still many more questions, and today Cassini has an opportunity to find some answers.

Cassini will be in a perfect position today to observe the light from Epsilon Orionis, the central star in Orion’s belt, as it passes through Enceladus’ plume. This type of observation is known as a stellar occultation, and it promises to provide new information about the composition and density of the plume. Cassini’s Ultraviolet Imaging Spectrograph (UVIS) will do the capturing, and once the information is relayed back to Earth, it will be analyzed for clues.

An artist's impression of the plumes coming from Enceladus. Image: NASA/JPL. — An artist’s impression of the plumes coming from Enceladus. Image: NASA/JPL.

We already know a few things about Enceladus’ plumes. First of all, Enceladus itself is any icy world, with subsurface oceans. The moon is locked in an orbital resonance, which creates its eccentric orbit. This eccentric orbit is responsible for heating the south polar oceans, which drives material through the ice sheets and creates its stunning plumes, in a process known as cryovolcanism. (Radioactive decay might also have something to do with heating.)

Cassini has been at Saturn’s system for 12 years, and has gradually painted a more detailed picture of Enceladus. Over time, we’ve learned that the plumes themselves are similar to what comets are made of. Cassini initially detected mostly water vapor, with traces of molecular nitrogen, methane, and carbon dioxide. Later, the presence of the hydrocarbons propane, formaldehyde, and acetylene was confirmed.

This is all very interesting, but why would anyone other than chemistry geeks care? Because the universe, including our Solar System, is largely a cold, sterile place. And the plumes coming from Enceladus indicate the presence of water, potentially warm, salty, water at that. And warm water might mean life, or the potential for life.

Cassini has previously observed two other stellar occultations. But with today’s observation, we stand to learn even more about the plumes of Enceladus. We’ll not only learn more about their density and composition, but since is the third such occultation to be observed, we’ll learn something about the plume’s behaviour over time. We probably won’t learn anything definitive about Enceladus’ life-supporting potential, but we will almost certainly find another piece of the puzzle, and fill in a blank spot in our knowledge.

And that’s what science is all about.