Matt Williams is a space journalist and science communicator for Universe Today and Interesting Engineering. He's also a science fiction author, podcaster (Stories from Space), and Taekwon-Do instructor who lives on Vancouver Island with his wife and family.
The planet Venus, as imaged by the Magellan 10 mission. The planet's inhospitable surface makes exploration extremely difficult. Credit: NASA/JPL
Venus is often refereed to as “Earth’s sister planet”, thanks to the number of things it has in common with our planet. As a terrestrial planet, it is similarly composed of silicate rock and metals – which are differentiated between a metal core and a silicate crust and mantle. It also orbits within our Sun’s habitable zone, and had a similarly violent volcanic past.
But of course, there are also some major differences between our two planets. For one, Venus has an atmosphere that is incredibly dense (92 times that of Earth, in fact) and reaches temperatures that are hot enough to melt lead. In addition, the planet’s rotation is immensely slow by comparison, taking 243.025 days to complete a single rotation, and rotating backwards relative to Earth.
When discussing Venus’ rotation, it is important to note certain distinctions. Rotation is the time it takes for a planet to spin once on its axis. This is different from a planet’s revolution, which is the time it takes for a planet to orbit around another object (i.e. the Sun). So while it takes the Earth one day (24 hours) to rotate once on its axis, it takes one year (365.256 days) to revolve once around the Sun.
Earth and Venus’ orbit compared. Credit: Sky and Telescope
Orbital Period:
In Venus’ case, things work a little differently. For starters, it orbits the Sun at an average distance of about 0.72 AU (108,000,000 km; 67,000,000 mi) with almost no eccentricity. In fact, with its farthest orbit (aphelion) of 0.728 AU (108,939,000 km) and closest orbit (perihelion) of 0.718 AU (107,477,000 km), it has the most circular orbit of any planet in the Solar System.
The planet completes a revolution around the Sun every 224.65 Earth days, which means that a year on Venus last about 61.5% as long as a year on Earth. Evey 584 days, Venus completes an interior conjunction, where it lies between Earth and the Sun. It is at this point that Venus makes the closest approach to Earth of any planet, at an average distance of 41 million km.
Rotational Period:
Unlike most other planets in the Solar System, which rotate on their axes in an counter-clockwise direction, Venus rotates clockwise (called “retrograde” rotation). It also rotates very slowly, taking 243.025 Earth days to complete a single rotation. This is not only the slowest rotation period of any planet, it also means that a single day on Venus lasts longer than a Venusian year.
Phases of Venus during 2004 photographed through a telescope. When very close to inferior conjunction (bottom right) the crescent is seen to extend fully around the planet. Credit: Statis Kalyva / Wikipedia
And, as noted earlier, Venus’ rotation is backwards, relative to Earth and the other bodies in the Solar System. Technically, this means that its rotational period is -243,025 days. It also means that if you could view the Solar System from the position above its celestial north pole, all of the planets (except for Uranus, which rotates on its side!) would appear to be rotating clockwise.
Venus, however, would appear to be rotating in a clockwise direction. Because of this, if you could stand on the surface of Venus, you would witness the Sun rising in the west and setting in the east. But you would be waiting a very long time to see this happen! Read on to find out why…
Sidereal vs. Solar Day:.
Another important thing to consider is the difference between a sidereal day and a solar day. A sidereal day corresponds to the amount of time it takes for a planet to rotate once on its axis, which in Venus’ case takes 243.025 Earth days. A solar day, by contrast, refers to the amount of time it takes for the Sun to reappear at the same point in the sky (i.e. between one sunrise/sunset and the next).
A Venusian (aka. Cytherean) Solar Day is the equivalent to 116.75 days on Earth, which means that it takes almost 117 days for the sun to rise, set, and return to the same place in the sky. Doing the math, we then see that a single year on Venus (224.65 Earth days) works out to just 1.92 Venusian (solar) days. Not exactly the basis for a good calendar system, is it?
View of Venus from the Solar Dynamics Observatory. If viewed from the surface of Venus, the Sun would be moving from west to east in the sky. Credit: NASA/SDO
Yes, when it comes to the planet Venus, things work quite differently than they do here on Earth. Not only does a day last over half a year on our “Sister Planet”, but the Sun rises and sets on the opposite horizons, and travels across the sky in the opposite direction. The reason for this, according to astronomers, is that billions of years ago (early in the planet’s history) Venus was impacted by another large planet.
The combined momentum between the two objects averaged out to the current rotational speed and direction, causing Venus to spin very slowly in its current retrograde motion. Someday, if human beings colonize there (perhaps in floating cities) they will have to learn to get used to a day that lasts over 2800 Earth hours, not to mention sunrises and sunsets happening on the wrong horizon!
NASA has unveiled a new exercise device that will be used by Orion crews to stay healthy on their mission to Mars. Credit: NASA
Going into space comes with its share of risks. In addition to the possibility of a catastrophic failure happening during take-off or landing, and having your craft pinholed by a micrometeorite, there are also the dangers of spending extended periods in space. Beyond that, there are also the slow, degenerative effects that spending an extended amount of time in a weightless environment can have on your body.
While astronauts on the ISS have enough space for the work-out equipment they need to help reduce these effects (i.e. muscle degeneration and loss of bone density), long-range missions are another matter. Luckily, NASA has plans for how astronauts can stay healthy during their upcoming “Journey to Mars“. It’s known as the Resistive Overload Combined with Kinetic Yo-Yo (ROCKY) device, which will be used aboard the Orion spacecraft.
For years, engineers at NASA and in the private sector have been working to create the components that will take astronauts to the Red Planet in the 2030s. These include the Space Launch System (SLS) and the Orion Multi Purpose Crew Capsule. At the same time, scientists and engineers at the Ohio-based Zin Technologies company – with the support of the NASA Human Research Program’s Exploration Exercise Equipment project – were busy developing the equipment needed to keep the Martian crews healthy and fit in space.
Cutaway of the Orion crew module, showing the ROCKY exercise device in blue, below the side hatch that astronauts will use to get in and out of the spacecraft. Credit: NASA
One of the biggest challenges was making a device that is robust enough to provide a solid work-out, but still be compact and light-weight enough to fit inside the space capsule. What they came up with was ROCKY, a rowing machine-like tool that can accommodate both aerobic activity and strength training. Using loads that simulate up to 180 kg (400 pounds) of resistance, astronauts will be able to perform excises like squats, deadlifts and heel raises, as well as upper body exercises like bicep curls and upright rows.
In the past, astronauts aboard the ISS have relied on equipment like the Mini Exercise Device-2 or the Treadmill Vibration Isolation System (TVIS) to reduce the risks of bone-density loss and muscle degeneration. But as Gail Perusek – the deputy project manager for NASA’s Exploration Exercise Equipment project – explained, developing exercise equipment for the Journey to Mars required something new:
“ROCKY is an ultra-compact, lightweight exercise device that meets the exercise and medical requirements that we have for Orion missions. The International Space Station’s exercise devices are effective but are too big for Orion, so we had to find a way to make exercising in Orion feasible.”
The device can also be customized, and incorporates the best features from a second device known as the Device for Aerobic and Resistive Training (DART). These include a servo-motor programmed to deliver a load profile that feels very similar to free weights. The DART was developed by TDA Research, a Denver-based R&D company, with the support of NASA’s Small Business Innovation Research Program. It was evaluated alongside the ROCKY during the equipment selection process.
The ROCKY device in action. Credit: NASA
In addition to being used for the crewed mission to Mars, the ROCKY device is likely to become a permanent feature aboard the Orion capsule, which will make it a mainstay for all of NASA’s proposed long-duration missions.
As Cindy Haven, the project manager for the Exploration Exercise Equipment Project, explained: “Our long-term goal is to develop a device that’s going to work for us for exploration. Between now and the mission, we’ll have different phases where we’re going to evaluate it for functionality, usability and durability to refine its design.”
The ROCKY device will be tested for the first time on Exploration Mission-2 (EM-2), the first mission where the spacecraft will be launched with a crew aboard. Th ROCKY will be located near the side hatch of the spacecraft, which astronauts will use to get in and out of the capsule. After the Orion is launched, the crew’s seats will be collapsed to provide more interior space for the astronauts as they work out.
And while the early missions using the Orion capsule will span only a few weeks at a time, staying fit will be important in the unlikely event that the astronauts need to get out of the crew module unassisted after splashdown. In the meantime, NASA will be spending the next few years refining the device to optimize it not only for near-term crewed Orion missions, but for potential uses on future long-duration missions.
The ROCKY is likely to become a mainstay for future long-term missions using the Orion space capsule. Credit: NASA
These will include the all-important launch where the Orion will dock with a habitat in the area of space around the moon. These missions are part of Phase II of NASA’s Mars mission, which is known as the “Proving Ground” phase. Scheduled to begin in 2030, this phase will involve the last elements of the mission being launched to cis-lunar orbit, and then all the equipment being sent to near-Mars space for pre-deployment.
The development team that will oversee future refinements will include engineers and scientists from Glenn Research Center in Cleveland, Ohio, and Johnson Space Center in Houston. In addition to building the hardware and ensuring that it is certified for flight, they will also be responsible for incorporating lessons learned from the development of equipment built for the ISS.
If all goes well in the coming years, the team even plans to include ROCKY into the International Space Station’s already impressive array of workout machines. Just another way for the astronauts to beat the slow, degenerative effects of floating freely in space!
Rough visual comparison of Jupiter, Earth, and the Great Red Spot. Approximate scale is 44 km/px. Credit: NASA/Brian0918/ Wikipedia Commons
Ever since Galileo Galilei first observed Jupiter closely in 1610 using a telescope of his own design, scientists and astronomers have been immensely fascinated by the Jovian planet. Not only is it the Solar System’s largest planet, but there are still things about this world – despite centuries of research and numerous exploration missions – that continue to mystify even our greatest minds.
One of the main reasons for this is because Jupiter is so starkly different from what we Earth-dwellers consider to be normal. Between its incredible size, mass, composition, the mysteries of its magnetic and gravitational fields, and its impressive system of moons, its existence has shown us just how diverse planets can truly be.
Size, Mass and Density:
Earth’s has a mean radius of 6,371 km (3,958.8 mi), and a mass of 5.97 × 1024 kg, whereas Jupiter has a mean radius of 69,911 ± 6 km (43441 mi) and a mass of 1.8986×1027 kg. In short, Jupiter is almost 11 times the size of Earth, and just under 318 times as massive. However, Earth’s density is significantly higher, since it is a terrestrial planet – 5.514 g/cm3 compared to 1.326 g/cm³.
Because of this, Jupiter’s “surface” gravity is significantly higher than Earth normal – i.e. 9.8 m/s² or 1 g. While, as a gas giant, Jupiter has no surface per se, astronomers believe that within Jupiter’s atmosphere where the atmospheric pressure is equal to 1 bar (which is equal to Earth’s at sea level), Jupiter experiences a gravitational force of 24.79 m/s2 (which is the equivalent of 2.528 g).
Earth is a terrestrial planet, which means it is composed of silicate minerals and metal that are differentiated between a metal core and a silicate mantle and crust. The core itself is also differentiated, between an inner core and outer core (which spins in the opposite direction of Earth’s rotation). As one descends from the crust to the interior, temperatures and pressure increase.
The shape of Earth approximates that of an oblate spheroid, a sphere flattened along the axis from pole to pole such that there is a bulge around the equator. This bulge results from the rotation of Earth, and causes the diameter at the equator to be 43 kilometers (27 mi) larger than the pole-to-pole diameter.
In contrast, Jupiter is composed primarily of gaseous and liquid matter which is divided between a gaseous outer atmosphere and a denser interior. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.
The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.
Jupiter’s structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)
The denser interior is composed of roughly 71% hydrogen, 24% helium and 5% other elements by mass. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The core has also been inferred as being rocky, but this remains unknown as well.
And much like Earth, temperatures and pressures inside Jupiter increase dramatically toward the core. At the “surface”, the pressure and temperature are believed to be 10 bars and 340 K (67 °C, 152 °F). In the region where hydrogen becomes metallic, it is believed that temperatures reach 10,000 K (9,700 °C; 17,500 °F) and pressures 200 GPa. The temperature at the core boundary is estimated to be 36,000 K (35,700 °C; 64,300 °F) and the interior pressure at roughly 3,000–4,500 GPa.
Also like Earth, Jupiter’s shape is that of an oblate spheroid. In fact, Jupiter’s polar flattening is greater than that of Earth’s – 0.06487 ± 0.00015 compared to 0.00335. This is due to Jupiter’s rapid rotation on its axis, and is why the planet’s equatorial radius is approximately 4600 km larger than its polar radius.
Orbital Parameters:
Earth has a very minor orbital eccentricity (approx. 0.0167) and ranges in distance from 147,095,000 km (0.983 AU) from the Sun at perihelion to 151,930,000 km (1.015 AU) at aphelion. This works out to an average distance (aka. semi-major axis) of 149,598,261 km, which is the basis of a single Astronomical Unit (AU).
The orbits of the inner planets of the Solar System, with Jupiter and the donut-shaped asteroid belt is located between them. Credit: Wikipedia Commons
The Earth has an orbital period of 365.25 days, which is the equivalent of 1.000017 Julian years. This means that every four years (in what is known as a Leap Year), the Earth calendar must include an extra day. Though technically a full day is considered to be 24 hours long, our planet takes precisely 23h 56m and 4 s to complete a single sidereal rotation (0.997 Earth days). But combined with its orbital period around the Sun, the time between one sunrise and another (a Solar Day) is 24 hours.
Viewed from the celestial north pole, the motion of Earth and its axial rotation appear counterclockwise. From the vantage point above the north poles of both the Sun and Earth, Earth orbits the Sun in a counterclockwise direction. Earth’s axis is tilted also 23.4° towards the ecliptic of the Sun, which is responsible for producing seasonal variations on the planet’s surface. In addition to producing variations in temperature, this also results in variations in the amount of sunlight a hemisphere receives during the course of a year.
Meanwhile, Jupiter orbits the Sun at an average distance (semi-major axis) of 778,299,000 km (5.2 AU), ranging from 740,550,000 km (4.95 AU) at perihelion and 816,040,000 km (5.455 AU) at aphelion. At this distance, Jupiter takes 11.8618 Earth years to complete a single orbit of the Sun. In other words, a single Jovian year lasts the equivalent of 4,332.59 Earth days.
The banded appearance of Jupiter’s upper atmopshere, which is partly due to its rapid rotation. Credit: NASA
However, Jupiter’s rotation is the fastest of all the Solar System’s planets, completing a single rotation on its axis in slightly less than ten hours (9 hours, 55 minutes and 30 seconds). Therefore, a single Jovian year lasts 10,475.8 Jovian solar days.
Atmospheres:
Earth’s atmosphere is made up of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. As a rule, air pressure and density decrease the higher one goes into the atmosphere and the farther one is from the surface. However, the relationship between temperature and altitude is more complicated, and may even rise with altitude in some cases.
The troposphere contains roughly 80% of the mass of Earth’s atmosphere, with some 50% located in the lower 5.6 km (3.48 mi), making it denser than all its overlying atmospheric layers. It is primarily composed of nitrogen (78%) and oxygen (21%) with trace concentrations of water vapor, carbon dioxide, and other gaseous molecules.
Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth’s meteorological phenomena (clouds, rain, snow, lightning storms) take place. The one exception is the Thermoposphere, where the phenomena known as Aurora Borealis and Aurara Australis (aka. The Northern and Southern Lights) are known to take place.
As already noted, Jupiter’s atmosphere is composed primarily of hydrogen and helium, with trace amounts of other elements. Much like Earth, Jupiter experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere create a light show that is truly spectacular.
Jupiter also experiences violent weather patterns. Wind speeds of 100 m/s (360 km/h) are common in zonal jets, and can reach as high as 620 kph (385 mph). Storms form within hours and can become thousands of km in diameter overnight. One storm, the Great Red Spot, has been raging since at least the late 1600s. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear.
Jupiter is perpetually covered with clouds composed of ammonia crystals and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region.
Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. Credit: NASA/CXC/UCL/W.Dunn et al/STScI
There may also be a thin layer of water clouds underlying the ammonia layer, as evidenced by flashes of lightning detected in the atmosphere of Jupiter, which would be caused by the water’s polarity creating the charge separation needed for lightning. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth.
Moons:
Earth has only one orbiting satellite, The Moon. It’s existence has been known of since prehistoric times, and it has played a major role in the mythological and astronomical traditions of all human cultures and has a significant effect on Earth’s tides. In the modern era, the Moon has continued to serve as a focal point for astronomical and scientific research, as well as space exploration.
In fact, the Moon is the only celestial body outside of Earth that humans have actually walked on. The first Moon landing took place on July 20th, 1969, and Neil Armstrong was the first person to set foot on the surface. Since that time, a total of 13 astronauts have been to the Moon, and the research that they carried out has been instrumental in helping us to learn about its composition and formation.
Thanks to examinations of Moon rocks that were brought back to Earth, the predominant theory states that the Moon was created roughly 4.5 billion years ago from a collision between Earth and a Mars-sized object (known as Theia). This collision created a massive cloud of debris that began circling our planet, which eventually coalesced to form the Moon we see today.
Illustration of Jupiter and the Galilean satellites. Credit: NASA
The Moon is one of the largest natural satellites in the Solar System and is the second-densest satellite of those whose densities are known (after Jupiter’s satellite Io). It is also tidally locked with Earth, meaning that one side is constantly facing towards us while the other is facing away. The far side, known as the “Dark Side”, remained unknown to humans until probes were sent to photograph it.
The Jovian system, on the other hand, has 67 known moons. The four largest are known as the Galilean Moons, which are named after their discoverer, Galileo Galilei. They include: Io, the most volcanically active body in our Solar System; Europa, which is suspected of having a massive subsurface ocean; Ganymede, the largest moon in our Solar System; and Callisto, which is also thought to have a subsurface ocean and features some of the oldest surface material in the Solar System.
Then there’s the Inner Group (or Amalthea group), which is made up of four small moons that have diameters of less than 200 km, orbit at radii less than 200,000 km, and have orbital inclinations of less than half a degree. This groups includes the moons of Metis, Adrastea, Amalthea, and Thebe. Along with a number of as-yet-unseen inner moonlets, these moons replenish and maintain Jupiter’s faint ring system.
Jupiter also has an array of Irregular Satellites, which are substantially smaller and have more distant and eccentric orbits than the others. These moons are broken down into families that have similarities in orbit and composition, and are believed to be largely the result of collisions from large objects that were captured by Jupiter’s gravity.
In just about every way imaginable, Earth and Jupiter could not be more different. And there are still many things about the Jovian planet that we do not yet fully understand. Speaking of which, be sure to stay tuned to Universe Today for the latest updates from NASA’s Juno mission.
A section of the 3D map constructed by BOSS. The rectangle on the far left shows a cutout of 1000 sq. degrees in the sky containing nearly 120,000 galaxies, or roughly 10% of the total survey. Credit: Jeremy Tinker/SDSS-III
In 1929, Edwin Hubble forever changed our understanding of the cosmos by showing that the Universe is in a state of expansion. By the 1990s, astronomers determined that the rate at which it is expanding is actually speeding up, which in turn led to the theory of “Dark Energy“. Since that time, astronomers and physicists have sought to determine the existence of this force by measuring the influence it has on the cosmos.
The latest in these efforts comes from the Sloan Digital Sky Survey III (SDSS III), where an international team of researchers have announced that they have finished creating the most precise measurements of the Universe to date. Known as the Baryon Oscillation Spectroscopic Survey (BOSS), their measurements have placed new constraints on the properties of Dark Energy.
The new measurements were presented by Harvard University astronomer Daniel Eisenstein at a recent meeting of the American Astronomical Society. As the director of the Sloan Digital Sky Survey III (SDSS-III), he and his team have spent the past ten years measuring the cosmos and the periodic fluctuations in the density of normal matter to see how galaxies are distributed throughout the Universe.
An illustration of baryon acoustic oscillations, which are imprinted in the early universe and can still be seen today in galaxy surveys like BOSS. Credit: Chris Blake and Sam Moorfield
And after a decade of research, the BOSS team was able to produce a three-dimensional map of the cosmos that covers more than six billion light-years. And while other recent surveys have looked further afield – up to distances of 9 and 13 billion light years – the BOSS map is unique in that it boasts the highest accuracy of any cosmological map.
In fact, the BOSS team was able to measure the distribution of galaxies in the cosmos, and at a distance of 6 billion light-years, to within an unprecedented 1% margin of error. Determining the nature of cosmic objects at great distances is no easy matter, due the effects of relativity. As Dr. Eisenstein told Universe Today via email:
“Distances are a long-standing challenge in astronomy. Whereas humans often can judge distance because of our binocular vision, galaxies beyond the Milky Way are much too far away to use that. And because galaxies come in a wide range of intrinsic sizes, it is hard to judge their distance. It’s like looking at a far-away mountain; one’s judgement of its distance is tied up with one’s judgement of its height.”
In the past, astronomers have made accurate measurements of objects within the local universe (i.e. planets, neighboring stars, star clusters) by relying on everything from radar to redshift – the degree to which the wavelength of light is shifted towards the red end of the spectrum. However, the greater the distance of an object, the greater the degree of uncertainty.
An artist’s concept of the latest, highly accurate measurement of the Universe from BOSS. Credit: Zosia Rostomian/Lawrence Berkeley National Laboratory
And until now, only objects that are a few thousand light-years from Earth – i.e. within the Milky Way galaxy – have had their distances measured to within a one-percent margin of error. As the largest of the four projects that make up the Sloan Digital Sky Survey III (SDSS-III), what sets BOSS apart is the fact that it relies primarily on the measurement of what are called “baryon acoustic oscillations” (BAOs).
These are essentially subtle periodic ripples in the distribution of visible baryonic (i.e. normal) matter in the cosmos. As Dr. Daniel Eisenstein explained:
“BOSS measures the expansion of the Universe in two primary ways. The first is by using the baryon acoustic oscillations (hence the name of the survey). Sound waves traveling in the first 400,000 years after the Big Bang create a preferred scale for separations of pairs of galaxies. By measuring this preferred separation in a sample of many galaxies, we can infer the distance to the sample.
“The second method is to measure how clustering of galaxies differs between pairs oriented along the line of sight compared to transverse to the line of sight. The expansion of the Universe can cause this clustering to be asymmetric if one uses the wrong expansion history when converting redshifts to distance.”
With these new, highly-accurate distance measurements, BOSS astronomers will be able to study the influence of Dark Matter with far greater precision. “Different dark energy models vary in how the acceleration of the expansion of the Universe proceeds over time,” said Eisenstein. “BOSS is measuring the expansion history, which allows us to infer the acceleration rate. We find results that are highly consistent with the predictions of the cosmological constant model, that is, the model in which dark energy has a constant density over time.”
Discerning the large-scale structure of the universe, and the role played by Dark Energy, is key to unlocking its mysteries. Credit: NAOJ/CFHT/ SDSS
In addition to measuring the distribution of normal matter to determine the influence of Dark Energy, the SDSS-III Collaboration is working to map the Milky Way and search for extrasolar planets. The BOSS measurements are detailed in a series of articles that were submitted to journals by the BOSS collaboration last month, all of which are now available online.
And BOSS is not the only effort to understand the large-scale structure of our Universe, and how all its mysterious forces have shaped it. Just last month, Professor Stephen Hawking announced that the COSMOS supercomputing center at Cambridge University would be creating the most detailed 3D map of the Universe to date.
Relying on data obtained by the CMB data obtained by the ESA’s Planck satellite and information from the Dark Energy Survey, they also hope to measure the influence Dark Energy has had on the distribution of matter in our Universe. Who knows? In a few years time, we may very well come to understand how all the fundamental forces governing the Universe work together.
A team of NASA engineers has fashioned the world's first telescope mirrors made from carbon nanotubes. Credit: NASA
Ever since they were first produced, carbon nanotubes have managed to set off a flurry excitement in the scientific community. With applications ranging from water treatment and electronics, to biomedicine and construction, this should come as no surprise. But a team of NASA engineers from the Goddard Space Flight Center in Greenbelt, Maryland, has pioneered the use of carbon nanotubes for yet another purpose – space-based telescopes.
Using carbon nanotubes, the Goddard team – which is led by Dr. Theodor Kostiuk of NASA’s Planetary Systems Laboratory and Solar System Exploration Division – have created a revolutionary new type of telescope mirror. These mirrors will be deployed as part of a CubeSat, one which may represent a new breed of low-cost, highly effective space-based telescopes.
This latest innovation also takes advantage of another field that has seen a lot of development of late. CubeSats, like other small satellites, have been playing an increasingly important role in recent years. Unlike the larger, bulkier satellites of yesteryear, miniature satellites are a low-cost platform for conducting space missions and scientific research.
Dr. Ted Kostiuk (center), flanked by John Kolasinski (left), and Tilak Hewagama (right), holding mirrors made of carbon nanotubes in an epoxy resin. Credit: NASA/W. Hrybyk
Beyond federal space agencies like NASA, they also offer private business and research institutions the opportunity to conduct communications, research and observation from space. On top of that, they are also a low-cost way to engage students in all phases of satellite construction, deployment, and space-based research.
Granted, missions that rely on miniature satellites are not likely to generate the same amount of interest or scientific research as large-scale operations like the Juno mission or the New Horizons space probe. But they can provide vital information as part of larger missions, or work in groups to gather greater amounts of data.
With the help of funding from Goddard’s Internal Research and Development program, the team created a laboratory optical bench made of regular off-the-shelf components to test the telescope’s overall design. This bench consists of a series of miniature spectrometers tuned to the ultraviolet, visible, and near-infrared wavelengths, which are connected to the focused beam of the nanotube mirrors via an optic cable.
Using this bench, the team is testing the optical mirrors, seeing how they stand up to different wavelengths of light. Peter Chen – the president of Lightweight Telescopes a Maryland-based company – is one of the contractors working with the Goddard team to create the CubeSat telescope. As he was quoted as saying by a recent NASA press release:
“No one has been able to make a mirror using a carbon-nanotube resin. This is a unique technology currently available only at Goddard. The technology is too new to fly in space, and first must go through the various levels of technological advancement. But this is what my Goddard colleagues (Kostiuk, Tilak Hewagama, and John Kolasinski) are trying to accomplish through the CubeSat program.
The laboratory breadboard that is being used to test a conceptual telescope for use on CubeSat missions. Credits: NASA/W. Hrybyk
Unlike other mirrors, the one created by Dr. Kostiuk’s team was fabricated out of carbon nanotubes embedded in an epoxy resin. Naturally, carbon nanotubes offer a wide range of advantages, not the least of which are structural strength, unique electrical properties, and efficient conduction of heat. But the Goddard team also chose this material for their lenses because it offers a lightweight, highly stable and easily reproducible option for creating telescope mirrors.
What’s more, mirrors made of carbon-nanotubes do not require polishing, which is a time-consuming and expensive process when it comes to space-based telescopes. The team hopes that this new method will prove useful in creating a new class of low-cost, CubeSat space telescopes, as well as helping to reduce costs when it comes to larger ground-based and space-based telescopes.
Such mirrors would be especially useful in telescopes that use multiple mirror segments (like the Keck Observatory at Mauna Kea and the James Webb Space Telescope). Such mirrors would be a real cost-cutter since they can be easily produced and would eliminate the need for expensive polishing and grinding.
Other potential applications include deep-space communications, improved electronics, and structural materials for spacecraft. Currently, the production of carbon nanotubes is quite limited. But as it becomes more widespread, we can expect this miracle material to be making its way into all aspects of space exploration and research.
Artist's impression of The Milky Way Galaxy. Based on current estimates and exoplanet data, it is believed that there could be tens of billions of habitable planets out there. Credit: NASA
For thousand of years, astronomers and astrologers believed that the Earth was at the center of our Universe. This perception was due in part to the fact that Earth-based observations were complicated by the fact that the Earth is embedded in the Solar System. It was only after many centuries of continued observation and calculations that we discovered that the Earth (and all other bodies in the Solar System) actually orbits the Sun.
Much the same is true about our Solar System’s position within the Milky Way. In truth, we’ve only been aware of the fact that we are part of a much larger disk of stars that orbits a common center for about a century. And given that we are embedded within it, it has been historically difficult to ascertain our exact position. But thanks to ongoing efforts, astronomers now know where our Sun resides in the galaxy.
Size of the Milky Way:
For starters, the Milky Way is really, really big! Not only does it measure some 100,000–120,000 light-years in diameter and about 1,000 light-years thick, but up to 400 billion stars are located within it (though some estimates think there are even more). Since one light year is about 9.5 x 1012 km (9.5 trillion km) long, the diameter of the Milky Way galaxy is about 9.5 x 1017 to 11.4 x 1017 km, or 9,500 to 11,400 quadrillion km.
It became its current size and shape by eating up other galaxies, and is still doing so today. In fact, the Canis Major Dwarf Galaxy is the closest galaxy to the Milky Way because its stars are currently being added to the Milky Way’s disk. And our galaxy has consumed others in its long history, such as the Sagittarius Dwarf Galaxy.
And yet, our galaxy is only a middle-weight when compared to other galaxies in the local Universe. Andromeda, the closest major galaxy to our own, is about twice as large as our own. It measures 220,000 light years in diameter, and has an estimated 400-800 billion stars within it.
Structure of the Milky Way:
If you could travel outside the galaxy and look down on it from above, you’d see that the Milky Way is a barred spiral galaxy. For the longest time, the Milky Way was thought to have 4 spiral arms, but newer surveys have determined that it actually seems to just have two spiral arms, called Scutum–Centaurus and Carina–Sagittarius.
The spiral arms are formed from density waves that orbit around the Milky Way – i.e. stars and clouds of gas clustered together. As these density waves move through an area, they compress the gas and dust, leading to a period of active star formation for the region. However, the existence of these arms has been determined from observing parts of the Milky Way – as well as other galaxies in our universe.
The Milky Way’s basic structure is believed to involve two main spiral arms emanating from opposite ends of an elongated central bar. Credit: T. Dame
In truth, all the pictures that depict our galaxy are either artist’s renditions or pictures of other spiral galaxies, and not the result of direct observation of the whole. Until recently, it was very difficult for scientists to gauge what the Milky Way really looks like, mainly because we’re inside it. It has only been through decades of observation, reconstruction and comparison to other galaxies that they have been to get a clear picture of what the Milky Way looks like from the outside.
From ongoing surveys of the night sky with ground-based telescopes, and more recent missions involving space telescopes, astronomers now estimate that there are between 100 and 400 billion stars in the Milky Way. They also think that each star has at least one planet, which means there are likely to be hundreds of billions of planets in the Milky Way – billions of which are believed to be the size and mass of the Earth.
As noted, much of the Milky Way’s arms is made up of dust and gas. This matter makes up a whopping 10-15% of all the “luminous matter” (i.e. that which is visible) in our galaxy, with the remainder being the stars. Our galaxy is roughly 100,000 light years across, and we can only see about 6,000 light years into the disk in the visible spectrum.
Still, when light pollution is not significant, the dusty ring of the Milky Way can be discerned in the night sky. What’s more, infrared astronomy and viewing the Universe in other, non-visible wavelengths has allowed astronomers to be able to see more of it.
The Milky Way, like all galaxies, is also surrounded by a vast halo of dark matter, which accounts for some 90% of its mass. Nobody knows precisely what dark matter is, but its mass has been inferred by observations of how fast the galaxy rotates and other general behaviors. More importantly, it is believed that this mass helps keep the galaxy from tearing itself apart as it rotates.
The Solar System:
The Solar System (and Earth) is located about 25,000 light-years to the galactic center and 25,000 light-years away from the rim. So basically, if you were to think of the Milky Way as a big record, we would be the spot that’s roughly halfway between the center and the edge.
Astronomers have agreed that the Milky Way probably has two major spiral arms – Perseus arm and the Scutum-Centaurus arm – with several smaller arms and spurs. The Solar System is located in a region in between the two arms called the Orion-Cygnus arm. This arm measures 3,500 light-years across and is 10,000 light-years in length, where it breaks off from the Sagittarius Arm.
The location of our Solar Systemin the Orion Spur of the Milky Way galaxy. Credit: Roberto Mura/Public Domain
The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the Solar System lies near the galactic plane. The Milky Way has a relatively low surface brightness due to the gases and dust that fills the galactic disk. That prevents us from seeing the bright galactic center or from observing clearly what is on the other side of it.
You might be surprised to learn that it takes the Sun 250 million years to complete one rotation around the Milky Way – this is what is known as a “Galactic Year” or “Cosmic Year”. The last time the Solar System was in this position in the Milky Way, there were still dinosaurs on Earth. The next time, who knows? Humanity might be extinct, or it might have evolved into something else entirely.
As you can see, the Milky Way alone is a very big place. And discerning our location within it has been no simple task. And as our knowledge of the Universe has expanded, we’ve come to learn two things. Not only is the Universe much larger than we could have ever imagined, but our place within in continues to shrink! Our Solar System, it seems, is both insignificant in the grand scheme of things, but also extremely precious!
Earth’s atmosphere seen from space. The top layer of the stratosphere is the ozone layer, which protects us from harmful solar UV. Scientists are tracking the ozone hole over the Antarctic. Credit: NASA
We here at Earth are fortunate that we have a viable atmosphere, one that is protected by Earth’s magnetosphere. Without this protective envelope, life on the surface would be bombarded by harmful radiation emanating from the Sun. However, Earth’s upper atmosphere is still slowly leaking, with about 90 tonnes of material a day escaping from the upper atmosphere and streaming into space.
And although astronomers have been investigating this leakage for some time, there are still many unanswered questions. For example, how much material is being lost to space, what kinds, and how does this interact with solar wind to influence our magnetic environment? Such has been the purpose of the European Space Agency’s Cluster project, a series of four identical spacecraft that have been measuring Earth’s magnetic environment for the past 15 years.
Understanding our atmosphere’s interaction with solar wind first requires that we understand how Earth’s magnetic field works. For starters, it extends from the interior of our planet (and is believed to be the result of a dynamo effect in the core), and reaches all the way out into space. This region of space, which our magnetic field exerts influence over, is known as the magnetosphere.
The four Cluster spacecraft crossing the northern cusp of Earth’s magnetosphere. Credit: ESA/AOES Medialab
The inner portion of this magnetosphere is called the plasmasphere, a donut-shaped region which extends to a distance of about 20,000 km from the Earth and co-rotates with it. The magnetosphere is also flooded with charged particles and ions that get trapped inside, and then are sent bouncing back and forth along the region’s field lines.
At its forward, Sun-facing edge, the magnetosphere meets the solar wind – a stream of charged particles flowing from the Sun into space. The spot where they make contact is known as the “Bow Shock”, which is so-named because its magnetic field lines force solar wind to take on the shape of a bow as they pass over and around us.
As the solar wind passes over Earth’s magnetosphere, it comes together again behind our planet to form a magnetotail – an elongated tube which contains trapped sheets of plasma and interacting field lines. Without this protective envelope, Earth’s atmosphere would have been slowly stripped away billions of years ago, a fate that is now believed to have befallen Mars.
That being said, Earth’s magnetic field is not exactly hermetically sealed. For example, at our planet’s poles, the field lines are open, which allows solar particles to enter and fill our magnetosphere with energetic particles. This process is what is responsible for Aurora Borealis and Aurora Australis (aka. the Northern and Southern Lights).
An illustration showing the natural barrier Earth gives us against solar radiation. Credit: NASA.
At the same time, particles from Earth’s upper atmosphere (the ionosphere) can escape the same way, traveling up through the poles and being lost to space. Despite learning much about Earth’s magnetic fields and how plasma is formed through its interaction with various particles, much about the whole process has been unclear until quite recently.
As Arnaud Masson, ESA’s Deputy Project Scientist for the Cluster mission stated in an ESA press release:
“The question of plasma transport and atmospheric loss is relevant for both planets and stars, and is an incredibly fascinating and important topic. Understanding how atmospheric matter escapes is crucial to understanding how life can develop on a planet. The interaction between incoming and outgoing material in Earth’s magnetosphere is a hot topic at the moment; where exactly is this stuff coming from? How did it enter our patch of space?“
Given that our atmosphere contains 5 quadrillion tons of matter (that’s 5 x 1015, or 5,000,000 billion tons), a loss of 90 tons a day doesn’t amount to much. However, this number does not include the mass of “cold ions” that are regularly being added. This term is typically used to described the hydrogen ions that we now know are being lost to the magnetosphere on a regular basis (along with oxygen and helium ions).
Since hydrogen requires less energy to escape our atmosphere, the ions that are created once this hydrogen becomes part of the plasmasphere also have low energy. As a result, they have been very difficult to detect in the past. What’s more, scientists have only known about this flow of oxygen, hydrogen and helium ions – which come from the Earth’s polar regions and replenish plasma in the magnetosphere – for a few decades.
Illustration of ions flowing out from the polar cap towards the magnetotail. Credit: ESA – C. Carreau
Prior to this, scientists believed that solar particles alone were responsible for plasma in Earth’s magnetosphere. But in more recent years, they have come to understand that two other sources contribute to the plasmasphere. The first are sporadic “plumes” of plasma that grow within the plasmasphere and travel outwards towards the edge of the magnetosphere, where they interact with solar wind plasma coming the other way.
The other source? The aforementioned atmospheric leakage. Whereas this consists of abundant oxygen, helium and hydrogen ions, the cold hydrogen ions appear to play the most important role. Not only do they constitute a significant amount of matter lost to space, and may play a key role in shaping our magnetic environment. What’s more, most of the satellites currently orbiting Earth are unable to detect the cold ions being added to the mix, something which Cluster is able to do.
In 2009 and in 2013, the Cluster probes were able to characterize their strength, as well as that of other sources of plasma being added to the Earth’s magnetosphere. When only the cold ions are considered, the amount of atmosphere being lost o space amounts to several thousand tons per year. In short, its like losing socks. Not a big deal, but you’d like to know where they are going, right?
This has been another area of focus for the Cluster mission, which for the last decade and a half has been attempting to explore how these ions are lost, where they come from, and the like. As Philippe Escoubet, ESA’s Project Scientist for the Cluster mission, put it:
“In essence, we need to figure out how cold plasma ends up at the magnetopause. There are a few different aspects to this; we need to know the processes involved in transporting it there, how these processes depend on the dynamic solar wind and the conditions of the magnetosphere, and where plasma is coming from in the first place – does it originate in the ionosphere, the plasmasphere, or somewhere else?“
Color illustration showing the scale of planets in our solar system, focusing on Jupiter and Saturn. Credit: NASA
The reasons for understanding this are clear. High energy particles, usually in the form of solar flares, can pose a threat to space-based technology. In addition, understanding how our atmosphere interacts with solar wind is also useful when it comes to space exploration in general. Consider our current efforts to locate life beyond our own planet in the Solar System. If there is one thing that decades of missions to nearby planets has taught us, it is that a planet’s atmosphere and magnetic environment are crucial in determining habitability.
Within close proximity to Earth, there are two examples of this: Mars, which has a thin atmosphere and is too cold; and Venus, who’s atmosphere is too dense and far too hot. In the outer Solar System, Saturn’s moon Titan continues to intrigue us, mainly because of the unusual atmosphere. As the only body with a nitrogen-rich atmosphere besides Earth, it is also the only known planet where liquid transfer takes place between the surface and the atmosphere – albeit with petrochemicals instead of water.
Moreover, NASA’s Juno mission will spend the next two years exploring Jupiter’s own magnetic field and atmosphere. This information will tell us much about the Solar System’s largest planet, but it is also hoped to shed some light on the history planetary formation in the Solar System.
In the past fifteen years, Cluster has been able to tell astronomers a great deal about how Earth’s atmosphere interacts with solar wind, and has helped to explore magnetic field phenomena that we have only begun to understand. And while there is much more to be learned, scientists agree that what has been uncovered so far would have been impossible without a mission like Cluster.
The star system CVSO 30, which was found to have two exoplanets with extreme orbital periods. If you look closely, you can see 30c to the upper left of the star. Credit: ESO
Every planet in the Solar System has its own peculiar orbit, and these vary considerably. Whereas planet Earth takes 365.25 days to complete a single orbit about our Sun, Mars takes almost twice as long – 686.971 days. Then you have Jupiter and the other gas giants, which take between 11.86 and 164.8 years to orbit our Sun. But even with these serving as examples, astronomers were not prepared for what they found when they looked at CVSO 30.
This star system, which lies some 1200 light years from Earth, has been found in recent years to have two candidate exoplanets. These planets, which are many times the mass of Jupiter, were discovered by an international team of astronomers using both the Transit Method and Direct Imaging. And what they found was very interesting: one planet has an orbital period of less than 11 days while the other takes a whopping 27,000 years to orbit its parent star!
In addition to being a big surprise, the detection of these two planets using different methods was an historic achievement. Up until now, the vast majority of the over 2,000 exoplanets discovered have been detected thanks to indirect methods. These include the aforementioned Transit Method, which detects planets by measuring the dimming effect they cause when crossing their parent star’s path, and the Radial Velocity Method, which measures the gravitational effect planets have on their parent star.
In 2012, astronomers used the Transit Method to detect CVSO 30b, a planet with 5 to 6 times the mass of Jupiter, and which orbits its star at a distance of only 1.2 million kilometers (by comparison, Mercury orbits our Sun at a distance of 58 million kilometers). From these characteristics, CVSO 30b can be described as a particularly “hot-Jupiter”.
In contrast, Direct Imaging has been used to spot only a few dozen exoplanets. The reason for this is because it is typically quite difficult to detect the light reflected by a planet’s atmosphere due it being drowned out by the light of its parent star. It can also be quite demanding when it comes to the instrument involved. Still, compared to indirect methods, it can be more effective when it comes to exploring the remote regions of a star.
Thanks to the efforts of an international team of astronomers, who combined the use of the Keck Observatory in Hawaii, the ESO’s Very Large Telescope in Chile, and the Spanish National Research Council’s (CSIC) Calar Alto Observatory, CVSO 30c was spotted in remote regions around its parent star, orbiting at a distance of around 666 AU.
The details of the discovery were published in a paper titled “Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30“. In it, the researchers – who hail from such prestigious institutions as the Cerro Tololo Inter-American Observatory, the Jena Observatory, the European Space Agency and the Max Planck Institute for Astronomy – explained the methods used to find the exoplanet, and the significance of its discovery.
The star CVSO30, showing the two detection methods that revealed its exoplanet candidates. Credit: Keck Observatory/ESO/VLT/NACO
As Tobias Schmidt – of the University of Hamburg, the Astrophysical Institute and University Observatory Jena, and the lead author of the paper – told Universe Today via email:
“[30b and 30c] are both unusual on their own. CVSO 30b is the first transiting planet around a star as young as 2.5 million years. Published in 2012, all previously detected transiting planets were older than few hundred million years… It has been a surprise to find a planetary mass companion at 662 AU, or 662 times the distance from Earth to the Sun, from a primary star having only about 0.4 solar masses. According to the standard model, planets form in disks around the star. But none of the observed disks around such low-mass stars is large enough to form such an object.”
In other words, it is surprising to find two exoplanet candidates with several times the mass of Jupiter (aka. Super-Jupiters) orbiting a star as small as CVSO 30. But to find two exoplanets with such a disparity in terms of their respective distance from their star (despite being similar in mass) was particularly surprising.
Relying on high-contrast photometric and spectroscopic observations from the Very Large Telescope, the Keck telescopes and the Calar Alto observatory, the international team was able to spot 30c using a technique known as lucky imaging. This process, which is used by ground-based telescopes, involves many high-speed, quick exposure photos being taken to minimize atmospheric interference.
An artist’s conception of a T-type brown dwarf. Credit: Tyrogthekreeper/Wikimedia Commons.
What they found was an exoplanet with a wide orbit that was between 4 and 5 Jupiter masses, and was also very young – less than 10 million years old. What’s more, the spectroscopic data indicated that it is unusually blue for a planet, as most other planet candidates of its kind are very red. The researchers concluded from this that it is likely that 30c is the first young planet of its kind to be directly imaged.
They further concluded that 30 c is also likely the first “L-T transition object” younger than 10 million years to be found orbiting a star. L-T transition objects are a type of brown dwarf – objects that are too large to be considered planets, but too small to be considered stars. Typically they are found embedded in large clouds of gas and dust, or on their own in space.
Paired with its companion – 30 b, which is impossibly close to its parent star – 30 c is not believed to have formed at its current position, and is likely not stable in the long-term. At least, not where current models of planetary formation and orbit are concerned. However, as Prof. Schmidt indicated, this offers a potential explanation for the odd nature of these exoplanets.
“We do think this is a very good hint,” he said, “that the two objects might have formed regularly around the star at a separation comparable to Jupiter or Saturn’s separation from the Sun, then interacted gravitationally and were scattered to their current orbits. However this is still speculation, further investigations will try to prove this. Both have about the same mass of few Jupiter masses, the inner one might be even lower.”
The Very Large Telescoping Interferometer firing it’s adaptive optics laser. Credit: ESO/G. Hüdepohl
The discovery is also significant since it was the first time that these two detection methods – Transit and Direct Imaging – were used to confirm exoplanet candidates around the same star. In this case, the methods were quite complimentary, and present opportunities to learn more about exoplanets. As Professor Schmidt explained:
“Both Transit method and radial velocity method have problems finding planets around young stars, as the activity of young stars is disturbing the search for them. CVSO 30 b was the first very young planet found with these methods, currently a hand full of candidates exist. Direct imaging, on the other hand, is working best for young planets as they still contract and are thus self-luminous. It is therefore great luck that a far out planet was found around the very first young star hosting a inner planet…
“However, the real advantage of transit and direct imaging methods is that the two objects can now be investigated in greater detail. While we can use the direct light from the imaging for spectroscopy, i.e. split the light according to its wavelength, we hope to achieve the same for the inner planet candidate. This is possible as the light passes through the atmosphere of the planet during transits and some of the elements are absorbed by the composition material of the atmosphere. So we do hope to learn a lot about planet formation, thus also formation of the early Solar System and about young planets in particular from the CVSO 30 system.”
Since astronomers first began began to find exoplanet candidates in distant star systems, we have come to learn just how diverse our Universe really is. Many of the discoveries have challenged our notions about where planets can form around their parent star, while others have showed us that planets can take many different forms.
As time goes on and our exploration of the local Universe advances, we will be challenged to find explanations for how it all fits together. And from that, new and more comprehensive models will no doubt emerge.
The Five-hundred-metre Aperture Spherical Telescope (FAST) has just finished construction in the southwestern province of Guizhou. Credit: FAST
Relax, its not a space station! And according to the Chinese government, it’s for entirely peaceful purposes. It’s known as the Five-hundred-meter Aperture Spherical Telescope (FAST), a massive array that just finished construction in the southerwestern province of Guizhou, China. Equivalent in size to over 20 football fields joined end to end, it is the world’s largest radio telescope – thus ending the Arecibo Observatory’s 53 year reign.
As part of China’s growing commitment to space exploration, the FAST telescope will spend the coming decades exploring space and assisting in the hunt for extraterrestrial life. And once it commences operations this coming September, the Chinese expect it will remain the global leader in radio astronomy for the next ten or twenty years.
In addition to being larger than the Arecibo Observatory (which measures 305 meters in diameter), the telescope is reportedly 10 times more sensitive than its closest competitor – the steerable 100-meter telescope near Bonn, Germany. What’s more, unlike Arecibo (which has a fixed spherical curvature), FAST is capable of forming a parabolic mirror. That will allow researchers a greater degree of flexibility.
The Chinese Academy of Sciences (CAS) has spent the past five years building the telesccope, to the tune of 1.2-billion-yuan (180 million U.S. dollars). As the deputy head of the National Astronomical Observation, which is overseen by the CAS, Zheng Xiaonian was present at the celebrations marking the completion of the massive telescope.
As he was paraphrased as saying by the Xinhua News Agency: “The project has the potential to search for more strange objects to better understand the origin of the universe and boost the global hunt for extraterrestrial life.” Zheng was also quoted as saying that he expects FAST to be the global leader in radio astronomy for the next 10 to 20 years.
The construction of this array has also been a source of controversy. To protect the telescope from radio interference, Chinese authorities built FAST in Guizhou province’s isolated Dawodang depression, directly into the mountainside. However, to ensure that no magnetic disruptions are nearby, roughly 9,000 people are being removed from their homes and rehoused in the neighboring counties of Pingtang and Luodian.
Li Yuecheng is the secretary-general of the Guizhou Provincial Committee, which is part of the Chinese People’s Political Consultative Conference (CPPCC). As he was quoted as saying by the Xinhua News Agency, the move comes with compensation:
“The proposal asked the government to relocate residents within 5 kilometers of the Five-hundred-meter Aperture Spherical Telescope, or FAST, to create a sound electromagnetic wave environment… Each of the involved residents will get 12,000 yuan (1,838 U.S. dollars) subsidy from the provincial reservoir and eco-migration bureau, and each involved ethnic minority household with housing difficulties will get 10,000 yuan subsidy from the provincial ethnic and religious committee.”
China’s recent forays into space include the Chang’e-3 moon lander, seen here by the Yutu moon rover. Credit: CNSA/SASTIND/Xinhua/Marco Di Lorenzo/Ken Kremer
In addition, the construction of this telescope is seen by some as part of a growing desire on behalf of China to press its interests in the geopolitical realm. For instance, in their 2016 Annual Report to Congress, the Department of Defense indicated that China is looking to develop its space capabilities to prevent adversaries from being able to use space-based assets in a crisis. As the report states:
“In parallel with its space program, China continues to develop a variety of counterspace capabilities designed to limit or to prevent the use of space-based assets by the [Peoples’ Liberation Army’s] adversaries during a crisis or conflict… Although China continues to advocate the peaceful use of outer space, the report also noted China would ‘secure its space assets to serve its national economic and social development, and maintain outer space security.'”
However, for others, FAST is merely the latest step in China’s effort to become a superpower in the all-important domain of space exploration and research. Their other ambitions include mounting a crewed mission to the Moon by 2036 and building a space station (for which work has already begun). In addition, FAST will enable China to take part in another major area of space research, which is the search for extra-terrestrial life.
For decades, countries like the United States have leading this search through efforts like the SETI Institute and the Nexus for Exoplanet System Science (NExSS). But with the completion of this array, China now has the opportunity to make significant contributions in the hunt for alien intelligence.
In the meantime, the CAS’ scientists will be debugging the telescope and conducting trials in preparation for its activation, come September. Once it is operational, it will assist in other areas of research as well, which will include conducting surveys of neutral hydrogen in the Milky Way and other galaxies, as well as detecting pulsars and gravitational waves.
The three Lego figures inside: Galileo, Juno and Jupiter. Source: NASA
Given its historic importance – being just the second spacecraft to conduct a long-term mission to Jupiter – NASA was sure to outfit the Juno probe with some high-end memorabilia. These include the Galileo commemorative plaque*, which shows Galileo’s face and the words he wrote when he first observed Jupiter’s four largest moons in 1610 (known today as the Galilean Moons).
In addition, three commemorative figures (each measuring 4 cm high) were created especially for the mission. Created by Lego, these figurines depict the Roman god Jupiter, his wife Juno, and the astronomer Galileo Galilei – each holding an identifying object. Constructed from aluminum so they could withstand the trip and the radiation of the gas giant, these figures arrived with the probe around Jupiter on Monday, July 4th.
Much like the Juno spacecraft that is ferrying them, these figurines have spent the past 5 years in space and traversing the 869 million kilometers that lie between Earth from Jupiter. As part of Lego’s “Build Your Future” campaign, the trio are part of an educational outreach program to inspire kids around the world to learn about science and technology.
A key part of this effort is the Building Challenge launched by Lego to raise awareness about space exploration. For this challenge, participants are asked to build their vision of the future of space exploration using Lego bricks, take pictures of their creation, and then upload them to the Lego website’s “Mission to Space” gallery. The winning creations will be featured on LEGO.com and the Gallery homepage.
NASA’s Juno spacecraft launched on August 6, 2011 and should arrive at Jupiter on July 4, 2016. Credit: NASA / JPL
In addition, Lego’s website has new content that encourages children to learn more about the Solar System. As they state on the webpage:
“Have you ever wondered what it would be like if you could visit other planets and travel through space? Well, here’s your chance to go on a mission to Space through a partnership between NASA and LEGO Group! Pack your space lunch, and get ready to fly the International Space Station, pass the Moon, to Mars and Jupiter! Learn fun facts about our solar system, play quizzes, and get a taste of life as an astronaut and space pioneer! Round off the trip by entering an out-of-this-world building challenge.”
True to their mythological roots, the figurine of Jupiter (the Roman equivalent of Zeus) is holding a lightning bolt. Juno, his wife, is holding a magnifying glass, which represents her ability to see through the clouds that Jupiter surrounded himself with. And Galileo, the famed astronomer who was the first to view Jupiter’s moons, holds his famed telescope and an orb representing Jupiter.
These three figurines are the closest thing the Juno spacecraft has to a crew. During the next two years, they will be with the probe as it orbits Jupiter a total of 37 times, conducting surveys of Jupiter’s atmosphere, interior, magnetosphere, and gravitational field. When the mission is over, they will deorbit with the probe, crashing into Jupiter’s atmosphere to prevent any contamination of Jupiter’s moons.
Three LEGO figurines representing the Roman god Jupiter, his wife Juno and Galileo Galilei are shown here aboard the Juno spacecraft. Credits: NASA/JPL-Caltech/KSC
Over the course of the past three days, numerous memes have popped up across the internet, claiming that: “When Galileo first spotted Jupiter’s largest moons, he named them after Jove’s (Zeus’) mistresses. Now, a probe named after his wife will arrive in the system, thus fulfilling a joke astronomers have been setting up for the past 400 years!” – I’m paraphrasing, of course!
Nevertheless, the observation is an apt one. And to make this witty statement complete, all those figures who had a hand in lending Jupiter the cultural significant it has (be they historical or mythological) will be represented as Juno tries to unveil Jupiter’s mysteries. Sure, those likenesses are just 4 cm in height, and they are built out of aluminum instead of marble, but it’s the thought that counts!
*The Galileo commemorative plague contains script written in Italian by Galileo’s own hand. It reads:
“On the 11th it was in this formation, and the star closest to Jupiter was half the size than the other and very close to the other so that during the previous nights all of the three observed stars looked of the same dimension and among them equally afar; so that it is evident that around Jupiter there are three moving stars invisible till this time to everyone.”
And be sure to enjoy this video of NASA’s Juno team celebrating the probe’s arrival at Jupiter:
