Fraser Cain, Author at Universe Today

September 3, 2013March 16, 2017 by Fraser Cain

How Big is the Solar System?

For most of us, stuck here on Earth, we see very little of the rest of the Solar System. Just the bright Sun during the day, the Moon and the planets at night. But in fact, we’re embedded in a huge Solar System that extends across a vast amount of space.

Which begs the question, just how big is the Solar System?

Before we can give a sense of scale, let’s consider the units of measurement.

Distances in space are so vast, regular meters and kilometers don’t cut it. Astronomers use a much larger measurement, called the astronomical unit. This is the average distance from the Earth to the Sun, or approximately 150 million kilometers.

Mercury is only 0.39 astronomical units from the Sun, while Jupiter orbits at a distance of 5.5 astronomical units. And Pluto is way out there at 39.2 astronomical units.

That’s the equivalent of 5.9 billion kilometers.

If you could drive your car at highway speeds, from the Sun all the way out to Pluto, it would take you more than 6,000 years to complete the trip.

But here’s the really amazing part. Our Solar System extends much, much farther than where the planets are.

The furthest dwarf planet, Eris, orbits within just a fraction of the larger Solar System.

The Kuiper Belt, where we find a Pluto, Eris, Makemake and Haumea, extends from 30 astronomical units all the way out to 50 AU, or 7.5 billion kilometers.

And we’re just getting started.

Artist's interpretation depicting the new view of the heliosphere. The heliosheath is filled with “magnetic bubbles” (shown in the red pattern) that fill out the region ahead of the heliopause. In this new view, the heliopause is not a continuous shield that separates the solar domain from the interstellar medium, but a porous membrane with fingers and indentations. Credit: NASA/Goddard Space Flight Center/CI Lab — Artist’s interpretation depicting the new view of the heliosphere. The heliosheath is filled with “magnetic bubbles” (shown in the red pattern) that fill out the region ahead of the heliopause. In this new view, the heliopause is not a continuous shield that separates the solar domain from the interstellar medium, but a porous membrane with fingers and indentations. Credit: NASA/Goddard Space Flight Center/CI Lab

Even further out, at about 80-200 AU is the termination shock. This is the point where the Sun’s solar wind, traveling outward at 400 kilometers per second collides with the interstellar medium – the background material of the galaxy. This material piles up into a comet-like tail that can extend 230 AU from the Sun.

But the true size of the Solar System is defined by the reach of its gravity; how far away an object can still be said to orbit the Sun.

The layout of the solar system, including the Oort Cloud, on a logarithmic scale. Credit: NASA

In the furthest reaches of the Solar System is the Oort Cloud; a theorized cloud of icy objects that could orbit the Sun to a distance of 100,000 astronomical units, or 1.87 light-years away. Although we can’t see the Oort Cloud directly, the long-period comets that drop into the inner Solar System from time to time are thought to originate from this region.

The Sun’s gravity dominates local space out to a distance of about 2 light-years, or almost half the distance from the Sun to the nearest star: Proxima Centauri. Believe it or not, any object within this region would probably be orbiting the Sun, and be thought to be a part of the Solar System.

Back to our car analogy for a second. At those distances, it would take you 19 million years to complete the journey to the edge of the Solar System. Even NASA’s New Horizons spacecraft, the fastest object ever launched from Earth would need 37,000 years to make the trip.

So as you can see, our Solar System is a really really big place.

August 27, 2013March 16, 2017 by Fraser Cain

Should Robots or Humans Explore Space?

You might be surprised to know that I have an opinion. People often ask me for it, but tend not to give it. But I was getting into a discussion with Amy Shira Teitel from Vintage Space about the priorities of humans versus robots for space explorations and offered up this opinion.

On matters of humans versus robots exploring space, this is what I think. Both, with different agendas.

Opinion: Should Robots or Humans Explore Space?

What’s the best way to explore the Solar System? Should we send humans, or robots? Robots are durable and replaceable, while humans are creative and flexible.

Space advocates line up on both sides of this discussion, and the debate can get heated.

Really heated.

Don’t be fooled. This whole conversation is a red herring.

We shouldn’t have to choose between human space exploration and robotic science, and it is absolutely ridiculous that the funding for it comes into a single agency.

The future of humanity will depend on us learning to live in space; to get off this planet and spread to the rest of the Solar System. The longer we remain trapped on this planet, the greater risk we face from a global catastrophe; whether it’s from an asteroid strike or a global plague.

We, as a species, are keeping all our eggs in one basket,

I don’t need to tell you how important science is. Our modern marvels are a direct result of the scientific method. The fact that you can even see this video (well, or read this article) should be all you need to know about the importance of science.

And we have no idea what we’ll find out there in space when we go exploring.

Were it up to me, I’d separate space exploration into two agencies, with completely different agendas and budgets.

On the science side, we need a fleet of robotic spacecraft and satellites continuously launching into space. We’d settle on a rugged, multi-purpose vehicle, which carries a variety of payloads and scientific instruments.

Curiosity Rover snapped this self portrait mosaic

The Curiosity Rover was an amazing success, and NASA should just keep building more rovers exactly like it. Give it cameras, grinders and scoops, but then keep the instruments open to the scientific community. Every two years, another identical rover will blast off to the Red Planet, hurling a fresh set of instruments to a new location.

Let’s send a rover and an orbiter every two years to Mars, and similar probes to other worlds, only the scientific instruments would need change. In a few years, there would be versions of the exact same spacecraft orbiting planets, asteroids and moons.

Over time, our observation of the Solar System would extend outward like a nervous system, gathering scientific knowledge at a terrific rate.

Neil Armstrong and Buzz Aldrin plant the US flag on the Lunar Surface during 1st human moonwalk in history - exactly 44 years ago on July 20, 1969 during Apollo 1l mission. Credit: NASA — Neil Armstrong and Buzz Aldrin plant the US flag on the Lunar Surface during 1st human moonwalk in history – exactly 44 years ago on July 20, 1969 during Apollo 1l mission. Credit: NASA

For human space exploration, we need to learn to live in space in increasingly complex ways: low Earth orbit, lunar orbit, on the lunar surface, on Mars, on asteroids, at Saturn, in the Lagrange points, et cetera.

Remember the Gemini program back in the 1960s? Each mission was an incremental step more complicated than the previous one. On one mission, the goal was just to learn if humans could survive in space for 14 days. In another mission, the goal was just to learn how to dock two spacecraft together.

This gave NASA the knowledge they needed to attempt an ambitious human landing on the Moon.

Chris Hadfield in the Cupola of the ISS. Credit: NASA

Instead of flying in low-Earth orbit for decades, our human space program could continuously advance our knowledge of what it takes to survive – and eventually thrive – in space. If NASA investigates the technologies that the private sector considers too risky to invest in, it will help jump start space exploration.

In this modern era of budget cuts, it breaks my heart that people are forced to choose between space science and human exploration.

It shouldn’t be this way. They have almost nothing in common.

Let’s do science, because science is important.

And let’s put humans in space, because humanity is important.

August 23, 2013December 29, 2015 by Fraser Cain

Weekly Space Hangout – Aug. 23, 2013: Mars One, Zombie WISE, Luca Parmitano, Wave at Saturn

It’s time for the Weekly Space Hangout. This is our weekly rundown on all the big space news stories of the week, explained by a dedicated team of space journalists.

Host:Fraser Cain

Panel: Alan Boyle, Brian Koberlein, Jason Major, Nicole Gugliucci

Mars One Reaches 165,000 Entries
WISE Returns from the Dead
Luca Parmitano’s Chilling First-Hand Account of His Mishap in Space
Baby Stars Belch in their Mama’s Face
Mars, Not as Big as the Moon
Earth Waves At Saturn
Exoplanet with a Short Year

We broadcast the Weekly Space Hangout every Friday afternoon as a live Google+ Hangout. You can join us live on Google+, YouTube or right here on Universe Today every Friday at 12:00 pm Pacific / 3:00 pm Eastern.

August 23, 2013March 16, 2017 by Fraser Cain

How Did Life Begin?

No answers today, only a question. But it’s one of the most interesting and meaningful questions we can possibly ask.

Where does life come from?

How did we get from no life on Earth, to the rich abundance we see today?

Charles Darwin first published our modern theories of evolution – that all life on Earth is related; adapting and changing over time. Look at any two creatures on Earth and you can trace them back to a common ancestor. Humans and chimpanzees share a common ancestor from at least 7 million years ago.

Trace back far enough, and you’re related to the first mammal who lived 220 million years ago. In fact, you and bacteria can trace a family member who lived billions of years ago. Keep going back, and you reach the oldest evidence of life on Earth, about 3.9 billion years ago.

But that’s as far as evolution can take us.

The Earth has been around for 4.5 billion years, and those early years were completely hostile to life. The early atmosphere was toxic, and a constant asteroid bombardment churned the landscape into a worldwide ocean of molten rock.

As soon as the environment settled down to be relatively habitable, life appeared. Just half a billion years beyond the formation of the Earth.

So how did life make the jump from raw chemicals to the evolutionary process we see today? The term for this mystery is abiogenesis and scientists are working on several theories to explain it.

One of the first clues is amino acids, the building blocks of life. In 1953, Stanley Miller and Harold Urey demonstrated that amino acids could form naturally in the environment of the early Earth. They replicated the atmosphere and chemicals present, and then used electric sparks to simulate lightning strikes.

Amazingly, they found a variety of amino acids in the resulting primordial soup.

Other scientists replicated the experiment, even changing the atmospheric conditions to match other models of the early Earth. Instead of water, methane, ammonia and hydrogen, they wondered what would happen if the atmosphere contained hydrogen sulfide and sulfur dioxide from volcanic eruptions. Environments around volcanic vents at the bottom of the ocean might have been the perfect places to get life started, introducing heavier metals like iron and zinc. Perhaps ultraviolet rays from the younger, more volatile Sun, or abundant radiation from natural uranium deposits played a role in pushing life forward into an evolutionary process.

Artists concept of shredded asteroid around white dwarf (NASA/JPL-Caltech)

What if life didn’t start on Earth at all? What if the building blocks came from space, drifting through the cosmos for millions of years. Astronomers have discovered amino acids in comets, and even alcohol floating in distant clouds of gas and dust

Maybe it wasn’t the organic chemicals that came first, but the process of self organization. There are examples of inorganic chemicals and metals that can organize themselves under the right conditions. The process of metabolism came first, and then organic chemicals adopted this process.

Thermophilic (heat-loving) bacteria may be among the last living creatures on Earth, the study suggests. Credit: Mark Amend / NOAA Photo Library

It’s even possible that life formed multiple times on Earth in different eras. Although all life as we know it is related, there could be a shadow ecosystem of microbial life forms in our soil or oceans which is completely alien to us.

So how did life get here? We just don’t know.

Maybe we’ll discover life on other worlds and that will give us a clue, or maybe scientists will create an experiment that finally replicates the jump from non-life to life.

We may never discover the answer.

August 20, 2013March 16, 2017 by Fraser Cain

How Do Astronomers Find Other Planets?

Up until 20 years ago, the only planets astronomers were aware of were within our Solar System. They assumed others were out there, but none had ever been detected.

Today we know of almost a thousand planets orbiting other stars. They come in a wide variety of sizes. Some are smaller than Earth, and others are more massive than Jupiter. Some are found around solitary stars, while others are located in multiple star systems. In those systems, there can be individual or even multiple planets in orbit. In fact, recent surveys suggest there are planets orbiting every single star in the Milky Way.

So, what methods do astronomers use to find these “extrasolar planets”?

The first extrasolar planet was discovered in 1991.

It was found orbiting a pulsar, a dead star that rotates rapidly, firing out bursts of radiation on an eerily precise interval. As the planets orbit the pulsar, they pull it back and forth with their gravity. This slightly changes the wavelength of the radiation bursts streaming from the exotic star. Astronomers were able to measure these changes, and calculate the orbits of multiple planets.

Radial Velocity Method

The golden age of extrasolar planet discovery began in 1995 when a team from the University of Geneva discovered a planet orbiting the nearby star 51 Pegasi. Astronomers used spectroscopy to break up the light to reveal the elements in its stellar atmosphere. They carefully measured how the wavelengths of light were Doppler shifted over time, and used a technique known as the radial velocity method. They calculated the star’s average motion, and discovered slight variations, as if something was yanking the star towards and away from us.

That something, was a planet.

In fact, this planet was unlike anything we have in the Solar System. 51 Pegasi B has about half the mass of Jupiter and it orbits much closer to its parent star. Closer even, than Mercury to the Sun.

Until this discovery, astronomers didn’t think it was possible for planets to orbit this close, and have had to revise their theories on planetary formation. Many Hot Jupiter planets have been discovered since, some in even more extreme environments.

Gravitational Microlensing

Another method astronomers use to find planets is called gravitational microlensing. It works by carefully measuring the brightness of one star as it passes in front of another. The foreground star acts like a lens, focusing the light with its gravity and causing the star to brighten for a few hours. If the foreground star has planets, these will create a telltale spike in the light signature coming from the event.

Amateur astronomers around the world participate in microlensing studies, imaging stars quickly when an event is announced.

Transit Method

Of course clouds are no issue if you’re watching the Transit of Venus from the ISS or the Hinode spacecraft. Compare this Hinode Transit image published on APOD on June 9 and enhanced by Marco Di Lorenzo,

The most successful way of finding planets is the transit method.

This is where telescopes measure the total amount of light coming from a star, and detect a slight variation in brightness as a planet passes in front.

Using this technique, NASA’s Kepler Mission has turned up thousands of candidate planets. Including some less massive than Earth, and others in the star’s habitable zone.

From the Kepler data, It’s just a matter of time before the holy grail of planets is uncovered… an Earth-sized world, orbiting a Sun-like star within the habitable zone.

All of these techniques are limited as they require the planets to be orbiting directly between us and their star. If the planets orbit above or below this plane, we just can’t detect them.

Coronographs

There is another method in the works that would unleash the discovery of extrasolar planets, coronographs.

Imagine if you could block all the light from the star, and only see the planets in orbit. This technique has been used for observing the Sun’s atmosphere, but it requires much more precision to see distant stars.

One idea is to position a sunflower-shaped starshade in space, 125,000 km away from the observing telescope. This shade would just cover the star, dimming it by a factor of 10-billion. Light from the planets would leak around the edges.

A sophisticated instrument could even study the atmospheres of these planets, and possibly provide us with evidence of life.

We’re at an exciting time in the field of extrasolar planet research, and trust me, these clever astronomers are just getting started.

August 19, 2013August 19, 2013 by Fraser Cain

Virtual Star Party – Aug. 18, 2013

On this warm August evening, three astronomers shared their live view of the night sky for a Virtual Star Party. The Moon was nearly full, but instead of hating it, Mark Behrendt decided to bring it into our view for the evening. We also had fantastic views of several of the famous summer nebulae: the Lagoon, the Swan, Veil, Ring, and Dumbbell Nebula.

Fraser also demonstrated his terrible skills as a space agency director, launching a few virtual rockets in the Kerbal Space Program while we waited for telescopes to update.

Host: Fraser Cain

Commentator: David Dickinson

Astronomers: Gary Gonella, Stuart Forman, Mark Behrendt

We run the Virtual Star Party as a live Google+ Hangout on Air every Sunday night when it gets dark on the West Coast. In the summer, that means 9:00 pm Pacific / 12:00 am Eastern. You can view the show live from the Universe Today YouTube page, or right here on Universe Today; we’ll embed the video on the site right before we begin.

We’re always looking for more astronomers, so if this sounds like something you’d like to participate it, just drop me an email at [email protected].

August 16, 2013December 29, 2015 by Fraser Cain

Weekly Space Hangout – Aug. 16, 2013

Like your space news, but you just can’t handle reading any more? Then watch our Weekly Space Hangout, where we give you a rundown of all the big space news stories that broke this week.

Host: Fraser Cain

Panel: Brian Koberlein, David Dickinson, Nancy Atkinson, Nicole Gugliucci

Stories:
CIA Comes Clean About Area 51
Elon Musk’s Hyperloop
Space Fence Shut Down
Magnetar Discovered Near the Galactic Core
IAU Updates Their Naming Policy
Bright Nova in Delphinus

We record the Weekly Space Hangout every Friday at 12 pm Pacific / 3 pm Eastern as a live Google+ Hangout on Air. Join us live on YouTube, or you can listen to the audio after the fact on the 365 Days of Astronomy Podcast.

August 15, 2013March 16, 2017 by Fraser Cain

Can You Really Name a Star?

There are services which will let you name a star in the sky after a loved one. You can commemorate a special day, or the life of an amazing person. But can you really name a star?

The answer is yes, and no.

Names of astronomical objects are agreed upon by the International Astronomical Union. If this name sounds familiar, it’s the same people who voted that Pluto is not a planet.

Them.

There are a few stars with traditional names which have been passed down through history. Names like Betelgeuse, Sirius, or Rigel. Others were named in the last few hundred years for highly influential astronomers.

These are the common names, agreed upon by the astronomical community.

Most stars, especially dim ones, are only given coordinates and a designation in a catalog. There are millions and millions of stars out there with a long string of numbers and letters for a name. There’s the Gliese catalog of nearby stars, or the Guide Star Catalog which contains 945 million stars.

The IAU hasn’t taken on any new names for stars, and probably won’t ever. The bottom line is that numbers are much more useful for astronomers searching and studying stars.

But what about the companies that will offer to let you name a star? Each of these companies maintains their own private database containing stars from the catalog and associated star names. They’ll provide you with a nice certificate and instructions for finding it in the sky, but these names are not recognized by the international astronomical community.

You won’t see your name appearing in a scientific research journal. In fact, it’s possible that the star you’ve named with one organization will be given a different name by another group.

So can you really name a star after yourself or a loved one?

Yes, you can, in the same way that you can name an already-named skyscraper after yourself. Everyone else might keep calling it the Empire State Building, but you’ll have a certificate that says otherwise.

There are a few objects that can be named, and recognized by the IAU.

Fragments of Shoemaker-Levy 9 on approach to Jupiter (NASA/HST)

If you’re the first person to spot a comet, you’ll have it named after you, or your organization. For example, Comet Shoemaker-Levy was discovered simultaneously by Eugene Shoemaker and David Levy.

If you discover asteroids and Kuiper Belt Objects, you can suggest names which may be ratified by the IAU. Asteroids, as well as comets, get their official numerical designation, and then a common name.

The amateur astronomer Jeff Medkeff, who tragically died of liver cancer at age 40, named asteroids after a handful of people in the astronomy, space and skeptic community.

Artist's impression of Eris — Artist’s impression of Eris

Kuiper Belt Objects are traditionally given names from mythology. And so, Pluto Killer Mike Brown’s Caltech team suggested the names for Eris, Haumea and Makemake.

So what about extrasolar planets? Right now, these planets are attached to the name of the star. For example, if a planet is discovered around one of the closer stars in the Gliese catalog, it’s given a letter designation.

An organization called Uwingu is hoping to raise funds to help discover new extrasolar planets, and then reward those funders with naming rights, but so far, this policy hasn’t been adopted by the IAU.

Personally, I think that officially allowing the public to name astronomical objects would be a good idea. It would spur the imagination of the public, connecting them directly to the amazing discoveries happening in space, and it would help drive funds to underfunded research projects.

And that would be a good thing.

Note: You can also visit a non-profit adopt-a-star program that supports Kepler research called the Pale Blue Dot Adopt-A-Star project!

August 12, 2013March 16, 2017 by Fraser Cain

What Is A Quasar?

I love it when scientists discover something unusual in nature. They have no idea what it is, and then over decades of research, evidence builds, and scientists grow to understand what’s going on.

My favorite example? Quasars.

Astronomers first knew they had a mystery on their hands in the 1960s when they turned the first radio telescopes to the sky.

They detected the radio waves streaming off the Sun, the Milky Way and a few stars, but they also turned up bizarre objects they couldn’t explain. These objects were small and incredibly bright.

They named them quasi-stellar-objects or “quasars”, and then began to argue about what might be causing them. The first was found to be moving away at more than a third the speed of light.

But was it really?

An artist's conception of jets protruding from an AGN. — An artist’s conception of jets protruding from an AGN.

Maybe we were seeing the distortion of gravity from a black hole, or could it be the white hole end of a wormhole. And If it was that fast, then it was really, really far… 4 billion light years away. And it generating as much energy as an entire galaxy with a hundred billion stars.

What could do this?

Here’s where Astronomers got creative. Maybe quasars weren’t really that bright, and it was our understanding of the size and expansion of the Universe that was wrong. Or maybe we were seeing the results of a civilization, who had harnessed all stars in their galaxy into some kind of energy source.

Then in the 1980s, astronomers started to agree on the active galaxy theory as the source of quasars. That, in fact, several different kinds of objects: quasars, blazars and radio galaxies were all the same thing, just seen from different angles. And that some mechanism was causing galaxies to blast out jets of radiation from their cores.

But what was that mechanism?

This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below. Image credit: NASA/ESA — This artist’s concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below. Image credit: NASA/ESA

We now know that all galaxies have supermassive black holes at their centers; some billions of times the mass of the Sun. When material gets too close, it forms an accretion disk around the black hole. It heats up to millions of degrees, blasting out an enormous amount of radiation.

The magnetic environment around the black hole forms twin jets of material which flow out into space for millions of light-years. This is an AGN, an active galactic nucleus.

When the jets are perpendicular to our view, we see a radio galaxy. If they’re at an angle, we see a quasar. And when we’re staring right down the barrel of the jet, that’s a blazar. It’s the same object, seen from three different perspectives.

Supermassive black holes aren’t always feeding. If a black hole runs out of food, the jets run out of power and shut down. Right up until something else gets too close, and the whole system starts up again.

The Milky Way has a supermassive black hole at its center, and it’s all out of food. It doesn’t have an active galactic nucleus, and so, we don’t appear as a quasar to some distant galaxy.

We may have in the past, and may again in the future. In 10 billion years or so, when the Milky way collides with Andromeda, our supermassive black hole may roar to life as a quasar, consuming all this new material.

If you’d like more information on Quasars, check out NASA’s Discussion on Quasars, and here’s a link to NASA’s Ask an Astrophysicist Page about Quasars.

We’ve also recorded an entire episode of Astronomy Cast all about Quasars Listen here, Episode 98: Quasars.

Sources: UT-Knoxville, NASA, Wikipedia

August 12, 2013August 12, 2013 by Fraser Cain

Virtual Star Party – August 11, 2013

If you need a break from the Perseid Meteor Shower, come join us for a Virtual Star Party. This is where we connect up a bunch of telescopes into a Google+ Hangout on Air and broadcast the skies live.

Host: Fraser Cain
Astronomers: Scott Lewis, Thad Szabo, Gary Gonella and Bill McLaughlin.

We run the Virtual Star Party every Sunday night when it gets dark on the West Coast. In the summer time, that’s 9:00 pm Pacific/12:00 am Eastern. In the Winter time, we start at 5/8 (which is much better for the East Coasters).

We’re always looking for more astronomers to join us, especially from South America, where we can get a view of the southern skies. If you’d like to participate, drop me an email at [email protected].