Posted on by Nancy Atkinson

Identical Twin Stars Not So Identical

I’m lucky enough to have twin sons. They aren’t identical (one looks like me, the other looks like my husband – which is about as different as things get) but they have a lot of similarities. One of my favorite stories about having twins is the time we took the whole family out to a restaurant shortly after the twins were born. The waitress commented that our babies looked the same size, and we said, “Yes, they’re twins.” And she replied, “Oh really? How far apart in age are they?”

I used to think that waitress was a real ditz, but after seeing a press release today from Vanderbilt University, I’m wondering if the waitress was on to something, and maybe she was even an astronomer.

Astronomers recently found a very young pair of identical binary stars that have surprising differences in brightness, surface temperature and size. They also believe one of the stars formed significantly earlier than its twin. Astrophysicists have assumed that binary stars form simultaneously, and so this discovery forces theorists back to the drawing board to determine if their models can produce binaries with stars that form at different times.

The identical twins were discovered in the Orion Nebula, a well-known stellar nursery, 1,500 light years from Earth. The newly formed stars are about 1 million years old. With a full lifespan of about 50 billion years, that makes them equivalent to one-day-old human babies.

“Very young eclipsing binaries like this are the Rosetta stones that tell us about the life history of newly formed stars,” says Keivan Stassun, associate professor of astronomy at Vanderbilt University. He and Robert D. Mathieu from the University of Wisconsin-Madison headed up the project.

The astronomers calculated that these twin stars have nearly identical masses, about 41 percent that of the sun. According to current theories, mass and composition are the two factors that determine a star’s physical characteristics and dictate its entire life cycle. Because the two stars condensed from the same cloud of gas and dust they should have the same composition. And with identical mass and composition, they should be identical in every way. So the astronomers were surprised when they discovered that the twins exhibited significant differences in brightness, surface temperature and possibly size.

“The easiest way to explain these differences is if one star was formed about 500,000 years before its twin,” says Stassun. “That is equivalent to a human birth-order difference of about half of a day.”

Now, I have heard stories of twins being born several hours apart and even in different years (one late on Dec. 31, and the other early on Jan. 1) so, maybe this difference in star formation isn’t such a big deal, and it happens all the time. However, further study is needed.

But this new discovery may cause astronomers to readjust their estimates of the masses and ages of thousands of young stars less than a few million years old, as current estimates are based on models that presumed binary stars formed simultaneously.

Just like having twins causes you to readjust your entire life. But it’s a good readjustment.

Original News Source: Vanderbilt University (this link includes a nice multimedia presentation about the discovery)

Posted on by Nancy Atkinson

Feeding Your Black Hole is Easy

Worried about how you’re going to feed your black hole once it grows up and gets big? Have no fear. New data from the Chandra X-ray Observatory indicates that even the biggest black holes may feed just like the smallest ones. Using new observations and a detailed theoretical model, a research team compared the properties of the black hole of the spiral galaxy M81 with those of smaller, stellar mass black holes. The results show that big or little, black holes appear to eat similarly to each other, and produce a similar distribution of X-rays, optical and radio light. This discovery supports the implication of Einstein’s relativity theory that black holes of all sizes have similar properties.

M81 is about 12 million light years from Earth. In the center of M81 is a black hole that is about 70 million times more massive than the Sun, and generates energy and radiation as it pulls gas in the central region of the galaxy inwards at high speed.

In contrast, so-called stellar mass black holes, which have about 10 times more mass than the Sun, have a different source of food. These smaller black holes acquire new material by pulling gas from an orbiting companion star. Because the bigger and smaller black holes are found in different environments with different sources of material to feed from, a question has remained about whether they feed in the same way.

“When we look at the data, it turns out that our model works just as well for the giant black hole in M81 as it does for the smaller guys,” said Michael Nowak, from the Massachusetts Institute of Technology. “Everything around this huge black hole looks just the same except it’s almost 10 million times bigger.”

One of the implications of Einstein’s theory of General Relativity is that black holes are simple objects and only their masses and spins determine their effect on space-time. The latest research indicates that this simplicity manifests itself in spite of complicated environmental effects.

The model that Markoff and her colleagues used to study the black holes includes a faint disk of material spinning around the black hole. This structure would mainly produce X-rays and optical light. A region of hot gas around the black hole would be seen largely in ultraviolet and X-ray light. A large contribution to both the radio and X-ray light comes from jets generated by the black hole. Multi-wavelength data is needed to disentangle these overlapping sources of light.

Among actively feeding black holes the one in M81 is one of the dimmest, presumably because it is “underfed”. It is, however, one of the brightest as seen from Earth because of its relative proximity, allowing high quality observations to be made.

“It seems like the underfed black holes are the simplest in practice, perhaps because we can see closer to the black hole,” said Andrew Young of the University of Bristol in England. “They don’t seem to care too much where they get their food from.”
This work should be useful for predicting the properties of a third, unconfirmed class called intermediate mass black holes, with masses lying between those of stellar and supermassive black holes. Some possible members of this class have been identified, but the evidence is controversial, so specific predictions for the properties of these black holes should be very helpful.

In addition to Chandra, three radio arrays (the Giant Meterwave Radio Telescope, the Very Large Array and the Very Long Baseline Array), two millimeter telescopes (the Plateau de Bure Interferometer and the Submillimeter Array), and Lick Observatory in the optical were used to monitor M81.
The results of this study will appear in an upcoming issue of The Astrophysical Journal.

News Source: NASA’s Chandra Website

Posted on by Nancy Atkinson

Phoenix Digs Again; More Science Data on the Way

The Phoenix lander began digging in an area called “Wonderland” early Tuesday, taking its first scoop of soil from a polygonal surface feature within the “national park” region that mission scientists have been preserving for science. The lander’s Robotic Arm created the new test trench called “Snow White” on June 17, the 22nd Martian day, or sol that Phoenix has been on the Red Planet. However, all of the newly planned science activities will resume no earlier than Sol 24 as engineers look into how the spacecraft is handling larger than expected amounts of data.

During Tuesday’s dig, the arm didn’t reach the hard white material, possibly ice, which Phoenix exposed previously in the first trench it dug into the Martian soil. This trench was only 2 centimeters deep, and the previous trench (the Goldilocks-Dodo Trench) was about 5 cm deep.

So, scientists weren’t surprised at this, and in fact, finding no ice is what they expected and wanted. The Snow White trench is near the center of a relatively flat hummock, or polygon, named “Cheshire Cat,” where scientists predict there will be more soil layers or thicker soil above possible white material.

The Phoenix team plans at least one more day of digging deeper into the Snow White trench. They will study soil structure in the Snow White trench to decide at what depths they will collect samples from a future trench planned for the center of the polygon.

Meanwhile, the Thermal and Evolved-Gas Analyzer (TEGA) instrument continues its ongoing experiment in the first of its eight ovens, and the science team hasn’t yet released any data on the “cooking” at higher temperatures.

TEGA has eight separate tiny ovens to bake and sniff the soil to look for volatile ingredients, such as water. The baking is performed at three different temperature ranges. At the first two temperature ranges, TEGA didn’t detect any water molecules or organics in the soil.

News Source: Phoenix News

Posted on by Jerry Coffey

What Color is Jupiter?

Jupiter seen from Voyager. Image credit: NASA/JPL

The iconic images of Jupiter show that it reflects many shades of white, red, orange, brown, and yellow. The color of Jupiter changes with storms and wind in the planet’s atmosphere.

The colors of Jupiter’s atmosphere are created when different chemicals reflect the Sun’s light. Most of Jupiter is hydrogen and helium, but the top of its clouds are composed of ammonia crystals, with trace amounts of water ice and droplets, and possibly ammonium hydrosulfide. Powerful storms on Jupiter are created by the planet’s convection. That allows the storms to bring material, such as phosphorus, sulfur and hydrocarbons, from closer to the planet’s core to the tops of the clouds, causing the white, brown, and red spots that we see dotting the Jovian atmosphere. White spots appear to be cool storms, brown are warm, and red are hot storms.

Jupiter’s Great Red Spot is an extreme example of one of these storms. It has been raging for at least 400 years. It is thought to have first observed by Giovanni Cassini in the late 1600s. It was observed up close by NASA’s Pioneer 10 spacecraft when it made its flyby in 1974. Better and better images were captured by other spacecraft, including the Voyagers, Galileo, Cassini and New Horizons. A century ago, the Red Spot measured 40,000 km across, but now it measures roughly half that, and seems to be shrinking. Astronomers have no idea how long the spot will last nor why it has lasted so long. The storm is so large that it can be seen from Earth by any medium sized or larger telescope.

A more recent storm has developed on Jupiter that has captured the attention of astronomers. Officially dubbed Oval BA , but commonly referred to as Red Jr, this storm is about half the size of the famous Great Red Spot and almost exactly the same color. Oval BA first appeared in 2000 when three smaller spots collided and merged. Scientists theorize that the Great Red Spot may have been created in the same way.

Scientists have been using the color of Jupiter to understand the atmospheric workings of the planet. There are future missions scheduled to bring a more in depth understanding to light. Those missions are also going to study the interaction of the volcanoes on Io with the water ice on Europa. There should be some pretty awesome data coming in the next few years.

Here’s an article from Universe Today about the newly formed Red Spot Jr, and another article about how storms on Jupiter can form in just a single day.

Ask an astronomer for Kids has tackled the same question, and a comparison of Jupiter in true and false color.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
http://science.nasa.gov/science-news/science-at-nasa/2006/02mar_redjr/
http://www.nasa.gov/multimedia/imagegallery/image_feature_413.html

Posted on by Jerry Coffey

Size of Jupiter

Comparison of Jupiter and Earth. Image credit: NASA/JPL

No matter how you measure it, Jupiter is a larger than life planet. The size of Jupiter can be measured in four ways: mass, diameter, volume, and surface area. The mass of Jupiter is 1.9 x 1027 kg. It has an equatorial diameter of 143,000 km. The Jovian volume is 1.43 x 1015km3. The total surface area of Jupiter is 6.22 x 1010km2.

Jupiter’s mass is 318 times that of Earth’s and around 2.5 times that of the rest of the Solar System combined. Jupiter may be the most massive planet in our Solar System, but it would need another 50-80 times its current mass in order to begin fusing its hydrogen into helium and become a star. The planet’s diameter is 11.2 times larger than Earth’s. Jupiter’s volume is 1321 times larger than Earth’s and it’s surface area is 122 times that of Earth’s.

While the size of Jupiter makes it seem like the largest possible planet, it is not. TrES-4 is estimated to be 70% larger than Jupiter, but it is less massive and has a lower density. That means that it is, well…fluffy. It’s density is so low that it would float on water. The planet is located about 1,400 light-years away, and orbits its host star every 3.5 days. It orbits 7.2 million km from its star, reaching a temperature of 1,600 Kelvin. The discovery of TrES-4 was made by astronomers working with the Trans-atlantic Exoplanet Survey. To capture transiting planets, the network of telescopes take wide-field timed exposures of clear skies on as many nights as possible. Astronomers then measure the amount of light coming from every single star in the field to detect if any have changed in brightness. In the case of TrES-4, it dims the amount of light received by the star by about 1%. Scientists are trying to figure out how a planet with so little mass could get so large. ”TrES-4 appears to be something of a theoretical problem,” said Edward Dunham, Lowell Observatory Instrument Scientist. ”It is larger relative to its mass than current models of superheated giant planets can presently explain. Problems are good, though, since we learn new things by solving them.”

Jupiter’s size is amazing, but as we expand our knowledge of the Universe, we are finding that it is not nearly the largest possible planet. As TrES-4 has demonstrated, there are planets out there that defy our current understanding.

Here’s an article from Universe Today about how big planets can get, and another about a star that’s the size of Jupiter.

Here’s all the information you could want about Jupiter from Wikipedia, and more general Jupiter information from Nine Planets.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
NASA
http://www.lowell.edu/

Posted on by Jerry Coffey

Is There Water on Jupiter?

Jupiter and its moons. Image credit: NASA/JPL

One of the first things that many people ask about a planet is whether there is water or not. So, naturally, the question ”is there water on Jupiter?” has been asked many times. The answer is yes, there is a small amount of water, but it is not ”on” Jupiter. It is in the form of water vapor in the cloud tops.

Scientists were surprised to find only trace amounts of water on Jupiter. After all, they had reasoned that Jupiter should have more oxygen than the Sun. The oxygen would have combined with the more than abundant hydrogen in the Jovian atmosphere, thus making water a significant component. The trouble is that the Galileo space craft found that Jupiter’s atmosphere contains less oxygen than the Sun; therefore, water is a minor trace element in the atmosphere.

That does not mean that there is not significant amounts of water elsewhere in the Jovian system. A few of Jupiter’s moons have been found to have water or water ice in their atmosphere or on their surface. Europa is the most important source of water in the system. Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike oceans on Earth, this ocean is deep enough to cover the whole surface of Europa, and being far from the sun, the ocean surface is globally frozen over. Europa’s orbit is eccentric, so when it is close to Jupiter the tide is much higher than when it is at aphelion. Tidal forces raise and lower the sea beneath the ice, most likely causing the cracks seen in images of Europa’s surface. The tidal forces cause Europa to be warmer than it would otherwise be. The warmth of Europa’s liquid ocean could prove critical to the survival of simple organisms within the ocean, if they exist.

Some scientists at NASA believe that the ocean under Europa’s surface does not consist of water, but say light reflected from the moon’s icy surface bears the spectral fingerprints of hydrogen peroxide and strong acids, perhaps close to pH 0. They are not sure whether this is just a thin surface dusting or whether the chemicals come from the ocean below. The hydrogen peroxide certainly seems to be confined to the surface, as it is formed when charged particles trapped in Jupiter’s magnetosphere strike water molecules on Europa. On the other hand, parts of the surface are rich in water ice containing what appears to be an acidic compound. Robert Carlson of NASA’s Jet Propulsion Laboratory thinks this is sulfuric acid. He believes that up to 80 per cent of the surface ice on Europa may be concentrated sulfuric acid. He goes on to suggest that this may be confined to a layer formed by surface bombardment with sulfur atoms emitted by volcanoes on Io. Tom McCord of the Planetary Science Institute in Winthrop, Washington and Jeff Kargel of the US Geological Survey in Flagstaff, Arizona point out that the greatest concentrations of acid seem to be in areas where the surface has been broken by tidal forces. They believe that ocean liquid has gushed up through those cracks and the ocean is actually the source of all of the acid. This theory holds that the acid on the surface began as salts(mainly magnesium and sodium sulphates), but the intense surface radiation caused chemical reactions which left an icy crust containing a high concentration of sulfuric acid as well as other sulfur compounds. That means that the ocean is an acidic brine that would be destructive to life as we know it.

Giving the answer to ”is there water on Jupiter” is probably the simplest piece of information about the planet. Nearly everything else is open a lot of interpretation until more space craft are sent for additional exploration.

Here’s an article about how the water on Europa might actually be corrosive to life, and the discovery of an extrasolar planet that does have evidence of water.

The Nine Planets site has a great description of Jupiter, including its lack of water, and an old article about Galileo’s search for water on Jupiter.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
NASA: Jupiter
NASA: Europa

Posted on by Jerry Coffey

Discovery of Jupiter

Voyager at Jupiter. image credit: NASA/JPL

No one can definitively say when the discovery of Jupiter took place nor who discovered it. Why is it so hard? It is one of the five planets that can be seen in the night sky. Only Venus and the Moon are brighter. Frankly, it is nearly impossible to miss. NASA lists the planet as having been discovered by the Ancients. The planet is called Marduk in ancient Babylonian texts, Zeus in early Greek manuscripts, and Jupiter in Roman antiquity.

What is known are some of the firsts in the exploration of Jupiter. In 1610, Galileo Galilei turned his rudimentary telescope on Jupiter, and realized that it had 4 large moons orbiting it: Io, Europa, Ganymede and Callisto. This was an important discovery, because it demonstrated that Earth was not the center of the Universe as proponents of the geocentric view believed.

In the1660s, Giovanni Cassini used his telescope to discover spots and bands across the surface of Jupiter, and was able to estimate the planet’s rotational period. He is thought to be the first to observe the planet’s Great Red Spot, a giant storm that is still raging. Imagine a single storm that rages for over 450 years and is larger than the Earth.

The first spacecraft to visit Jupiter up close was NASA’s Pioneer 10 in 1973. That mission was closely followed by Pioneer 11 in 1974. Both of NASA’s Voyager spacecraft flew past in 1979, sending back many of the famous pictures we’re all familiar with. Since then, the Ulysses solar probe, NASA’s Cassini spacecraft and New Horizons have all made flybys of the planet.

The only spacecraft to actually orbit Jupiter was NASA’s Galileo mission, which went into orbit in 1995. NASA scientists were not satisfied with a few orbits of Jupiter. They wanted to see a bit more of the Jovian system, so Galileo was sent to observe a few moons. Galileo is credited as being the first spacecraft to observe a comet hitting a planet(Jupiter), first to flyby an asteroid, first to discover an asteroid with a moon, and it was the first to measure the crushing atmospheric pressure of Jupiter with a descent probe. The mission discovered evidence of subsurface saltwater on Europa, Ganymede and Callisto and revealed the intensity of the volcanic activity on Io.

We may not know the exact date of the discovery of Jupiter, but we know many first about the planet. Even now, scientists are planning the next mission and hoping to be the first to discover something about the Jovian system.

Here are some images of the Jupiter flyby from NASA’s New Horizons spacecraft, and an article about Cassini’s flyby of Jupiter.

Here’s the archived page for NASA’s Galileo mission to Jupiter, and information about the Voyager mission’s images of Jupiter.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=Facts
http://solarsystem.nasa.gov/galileo/

Posted on by Jerry Coffey

Mass of Jupiter

Jupiter and its moons. Image credit: NASA/JPL

The mass of Jupiter is 1.9 x 1027 kg. It is hard to fully understand a number that large, so here are a few comparisons to help. It would take 318 times Earth’s mass to equal Jupiter’s. Jupiter is 2.5 times more massive than all of the other planets in our Solar System combined. Jupiter is actually so massive that if it gained much more mass it would shrink.

How can additional mass cause a planet to shrink? Gravitational compression. Given that there is no more hydrogen or helium gas floating around for Jupiter to collect, it would gain mass through the accretion of rocky bodies like asteroids. Jupiter’s intense gravity would pull additional rock tightly together shrinking the diameter of the planet and increasing its density. As the density increased so would the gravity, further compressing the planet. Scientists estimate that Jupiter would have to accumulate 3-4 times its current mass in order to begin compressing. Since there isn’t that much material in our Solar System, it is a pretty good bet that Jupiter will never shrink.

But what if it did? There have been rumors floating around for decades that Jupiter could ignite fusion and become a star at any time. They are all false science and garbage at best. The mass of Jupiter is no where near enough for sustained nuclear fusion. Fusion requires high temperatures, intense gravitational compression, and fuel. Jupiter has the right fuels in abundance. There is plenty of hydrogen to be had, but the planet is too cold and lacks the density for a sustained reaction process. Scientists estimate that Jupiter needs 50-80 times its current mass to ignite fusion. As stated in the paragraph above, there isn’t enough material to be had, so Jupiter can not become a star.

At one time, scientists thought that Jupiter was the largest that a planet could become without igniting fusion and becoming a star. They discovered the fallacy of that belief once technology expanded their view of the universe. According to Dr. Sean Raymond, a post doctoral researcher at the Center for Astrophysics and Space Astronomy (CASA) at the University of Colorado, ”In terms of gaseous planets, once they reach 15 Jupiter masses or so there is enough pressure in the core to ignite deuterium fusion, so those are considered ‘brown dwarfs’ rather than planets.”

As you can see, the mass of Jupiter may seem awesome in comparison to Earth, it is a tiny fish in a world of sharks. Scientists have found a few hundred gas giants larger than Jupiter as they have surveyed the night sky. Who knows what is in store as telescope technology improves in the coming years.

Here’s an article from Universe Today explaining just how big planets can get, and an article about how Jupiter and the other gas giants might have gobbled up their moons while they were forming.

This site has more detailed information about the mass of Jupiter, and a page from NASA that helps you calculate the density of the planets.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter
http://planetquest.jpl.nasa.gov/news/tres4.cfm

Posted on by Nancy Atkinson

Just in Time for Summer: The Milky Way Loses Weight

The Milky Way and its dark matter halo. Image credit: Sloan Digital Sky Survey

Have you ever been surprised at your annual weigh-in at the doctor’s office to find that your bathroom scale at home was wrong? Or, bought a new scale that had a difference of opinion with your old one? That’s what has happened with our very own Galaxy, the Milky Way. “The Galaxy is slimmer than we thought,” said Xiangxiang Xue of the Max Planck Institute for Astronomy in Germany and the National Astronomical Observatories of China, who lead a research team using the Sloan Digital Survey to measure the mass of the stars in the galaxy. “We were quite surprised by this result,” said Donald Schneider, a member of the research team, from Penn State. The researchers explained that it wasn’t a Galactic diet that accounted for the galaxy’s recent slimming, but a more accurate scale.

The researchers used the motions of distant stars to make the new determination of the Milky Way’s mass. They measured the motions of 2,400 “blue horizontal branch” stars in the extended stellar halo that surrounds the disk of the galaxy. These measurements reach distances of nearly 200,000 light years from the Galactic center, roughly the edge of the region illustrated in the image above. Our Sun lies about 25,000 light years from the center of the Galaxy, roughly halfway out in the Galactic disk. From the speeds of these stars, the researchers were able to estimate much better the mass of the Milky Way’s dark-matter halo, which they found to be much ‘slimmer’ than thought before.

The discovery is based on data from the project known as SEGUE (Sloan Extension for Galactic Understanding and Exploration), an enormous survey of stars in the Milky Way. Using SEGUE measurements of stellar velocities in the outer Milky Way, a region known as the stellar halo, the researchers determined the mass of the Galaxy by inferring the amount of gravity required to keep the stars in orbit. Some of that gravity comes from the Milky Way stars themselves, but most of it comes the distribution of invisible dark matter, which is still not fully understood.

The most recent previous studies of the mass of the Milky Way used mixed samples of 50 to 500 objects. They implied masses up to two-trillion times the mass of the Sun for the total mass of the Galaxy. By contrast, when the SDSS-II measurement within 180,000 light years is corrected to a total-mass measurement, it yields a value slightly under one-trillion times the mass of the Sun.

“The enormous size of SEGUE gives us a huge statistical advantage,” said Hans-Walter Rix, director of the Max Planck Institute for Astronomy. “We can select a uniform set of tracers, and the large sample of stars allows us to calibrate our method against realistic computer simulations of the Galaxy.” Another collaborator, Timothy Beers of Michigan State University, explained, “The total mass of the Galaxy is hard to measure because we’re stuck in the middle of it. But it is the single most fundamental number we have to know if we want to understand how the Milky Way formed or to compare it to distant galaxies that we see from the outside.”

All SDSS-II observations are made from the 2.5-meter telescope at Apache Point Observatory in New Mexico. The telescope uses a mosaic digital camera to image large areas of sky and spectrographs fed by 640 optical fibers to measure light from individual stars, galaxies, and quasars. SEGUE’s stellar spectra turn flat sky maps into multi-dimensional views of the Milky Way, Beers said, by providing distances, velocities, and chemical compositions of hundreds of thousands of stars.

Source: Penn State, arXiv

Posted on by Nancy Atkinson

Interview in Australia Today (or is it tomorrow?)

Update: Well, I guess it will be tomorrow! Due to some technical difficulties with phones, we weren’t able to do the interview today, so will try again tomorrow, same time. Keeping fingers crossed it works then.

I (Nancy) will be doing a live interview on an Australian radio show called “The Starlight Zone” with Col Maybury of radio station 2NUR FM, a community radio station funded and operated by the University of Newcastle. For me, the interview will be on Wednesday Thursday at 3:50 pm (US Central Time) but in Australia it will actually be Thursday Friday morning at 6:50 am! How confusing! To keep it simple, the time is 20:50 Universal Time.

You can listen live HERE, (Look for the link on the left that says “Listen”) but I believe a recording will also be available later, and if so I’ll post it here at that time.

The interview will only be 5 minutes long, and from what Col has told me, he wants to ask me about the concept of a one-way mission to Mars (or maybe this one).

Hope you can listen in.