Question: Is it possible to detect moons orbiting distant exoplanets? How would this be accomplished?
Questions from the kids (2013-12-30) – If we use our own solar system as an example, we would expect exoplanets to have bodies similar to our own Moon orbiting them. Exomoons, as we’ll refer to them, would be small in comparison to their host planets, and this fact is going to make it more difficult to detect them at the extreme distances involved.
Despite this fact, astronomers believe exomoons should be detectable, using the same techniques and for the same reasons exoplanets are detected. Exomoons have mass, which means they’ll interact gravitationally with their host planet and sun, causing the exoplanet to move in a mathematically predictable manner in response to the force of gravity. The exomoon will constantly pull on the planet gravitationally, which changes the amount of time it takes the planet to pass in front of its host sun. If an exomoon lines up with its home sun from our point of view here on Earth, this would cause a resulting collection of dips in measured sunlight, just before or after the much more significant transits of the host planet in front of its star. Astronomers believe they can use this fact in the future, along with any new techniques they develop, to search for and find distant exomoons orbiting their home planets.
This detection technique is the most practical way astronomers have developed in order to search for and find distant exomoons. This method provides astronomers with a more direct technique to use in the search for exomoons and at present is the best way to do the job. Currently, NASA’s Kepler telescope, which is looking for smaller transiting exoplanets, is probably our best chance of finding a distant exomoon orbiting its home planet. The Kepler telescope really isn’t designed to search for and find distant exomoons, which makes the job a truly daunting task using this telescope. If we use the largest moon in our solar system, Jupiter’s Ganymede, as an example, we would find Ganymede’s diameter is only about 40 percent of Earth’s. This means Ganymede would only block about 0.0014 percent of the Sun’s light during any transit, which is around six times less than the amount blocked by an Earth transit.
All of this is based upon the data and information astronomers have concerning our own solar system, which could be too general, or just wrong. It could be Earth-sized moons orbit transiting planets as large as Jupiter or Saturn, which would mean Kepler would just be able to detect them, and make it possible to search for and find distant exomoons orbiting their home planets.
The best bet astronomers have of finding exomoons orbiting their home planets light-years away will probably be the James Webb Space Telescope once it comes online. This will be when the human journey to the beginning of space and time has the best chance of searching for and finding exomoons orbiting their home planets.
Astronomy news (2013-12-22) – Galileo might have dreamed of unseen life forms existing in a watery soup under the icy surface of Europa when he first discovered Jupiter had moons on January 07, 1610. NASA astronomers working with the Hubble Space Telescope probably had similar thoughts when they recently saw images of what appears to be water geysers erupting from the south pole of Europa. The image above shows an artist’s conception of what astronomers and scientists believe is plumes of water vapour reaching over 100 miles into space from the south pole of Europa.
Are there life forms or maybe just organic material of some type existing on this watery moon? NASA astronomers, space scientists and interested people around the world are hoping this news will spur NASA officials and congress to provide them with the resources they need to fund the Europa Clipper (a NASA mission designed to travel to Europa to see if the conditions required for life exist).
“If there’s a geyser 200 kilometers tall, and you could fly a spacecraft through it and sample the water coming out from Europa, that would be phenomenal. What if there are organics in it? That’s getting to the question of ‘Are we alone in the universe?’ ” said John Grunsfeld, NASA’s top official for space science. “A subsurface ocean at Europa potentially provides all conditions for microbial life — at least life we know,” says study lead author Lorenz Roth, a planetary scientist at the Southwest Research Institute in San Antonio, Texas.
Astronomers are currently taking a look at earlier data concerning Europa provided by the Voyager probes during the 1980s and Galileo spacecraft during the 1990s to see if they missed something. Astronomers and planetary scientists suspected back in the 1980s, when they first obtained the data from the Voyager probes, that Europa could have an ocean of water beneath its icy crust deeper and more massive than all of the oceans of Earth. The Galileo spacecraft also detected the magnetic signature of a subsurface ocean beneath the surface ice of Europa and brown regions on the ice planetary scientists think could be due to ice crystals containing possible organic material, formed from water vapor plumes like the ones recently viewed, being deposited on the surface of the moon.
Astronomers are also comparing this data to more recent information concerning Europa, they obtained last year through the repaired Hubble Space Telescope, to see if they can find the telltale signature of hydrogen and oxygen they’re looking for in the data. Water is composed of hydrogen and oxygen and this signature will help astronomers and planetary scientists determine if plumes of water vapour are in fact coming from Europa’s southern hemisphere.
“As it hit the vacuum of space, the water would flash freeze and some of it would turn into water vapour. Those water molecules would be split into atomic hydrogen and oxygen in the harsh radiation environment of the Jupiter system. But it wouldn’t just be water in the plume: Whatever else was in that ocean would be squirted into space, too, said James Green, head of NASA’s planetary science division. For a planetary scientist, it’s huge,” Green said of the news.
The image above shows spikes in hydrogen and oxygen levels in two southern hemisphere regions on Europa’s surface that last for brief periods of about seven hours and coincide with the moon reaching its farthest point from Jupiter in its orbit. Astronomers and planetary scientists think current computer models suggest the images obtained through the Hubble Space Telescope could show plumes of water vapour over a hundred miles high streaming into space from the surface of Europa. It remains puzzling to astronomers and scientists why the water vapour plumes seem to coincide with Europa reaching its apocenter, since this is the moment when tidal forces on the moon are at a low point (Astronomers estimate these tidal forces can be over 1,000 times stronger than the tidal forces our own moon experiences due to Earth). Current ideas include the thought that maybe the surface cracks on Europa’s southern pole open once Jupiter’s gravity starts to lessen, allowing water vapour to squeeze out in jets reaching over a hundred miles into space.
Astronomers and planetary scientists at NASA suggest Europa’s plumes are probably like geysers they found on Saturn’s moon Enceladus, which also seem to appear when the moon reaches its apocenter. They’re excited about this discovery because Europa is only about half as far from Earth than Enceladus, which will allow the Hubble Space Telescope to have a closer look, this time. They hope to be able to use this fact to confirm the discovery of water on Europa and Enceladus and possibly get some quantitative data on the size, density, composition and timing of the plumes. Analysis of the composition of the plumes should also give them the data they need to model the interior of the moon, without having to land on the surface and drill holes.
The implications of the discovery of water on both Enceladus and Europa is stunning to contemplate for human beings, astronomers, and planetary scientists. We believe the human journey to the beginning of space and time should voyage to both of these moons in the future to determine if the ingredients for life exist on these distant bodies. We need to do this for science, mankind and future generations of humanity.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. The Association of Universities for Research in Astronomy Inc. in Washington operates STScI for NASA.
To view the images of the evidence for plumes visit:
The spectacular image, seen below, is a panoramic composed of 141 wide-angle images, showing us a view 404,880 miles (651,591 kilometers) across of Earth, Venus, Mars, and Saturn and its moons and inner ring system. The image includes all of Saturn’s rings, including the E ring, which is the second ring from the outer edge of the planet’s rings (the distance between the Earth and the Moon would easily fit within the width of the E ring). “In this one magnificent view, Cassini has delivered to us a universe of marvels,” said Carolyn Porco, Cassini’s imaging team lead at the Space Science Institute in Boulder, Colo. “And it did so on a day people all over the world, in unison, smiled in celebration at the sheer joy of being alive on a pale blue dot.”
Join the Wave at Saturn Campaign
This spectacular image of Saturn and its moons and rings is part of NASA’s “Wave at Saturn” campaign, which invited people around the United States and the world to take part in a celebration and party on July 19. NASA asked people to take the time to find Saturn in the sky in their part of the world. To say hello to Cassini and the ringed planet by waving across the solar system and loading any pictures they take onto the Internet to be shared with the world. A fun and social way to join the human journey to the beginning of space and time.
The image above shows Earth as the bright blue dot located to the lower right of Saturn. Venus isn’t easily seen in this image and is the bright dot located to the upper left of the giant planet, while Mars is the faint red dot to the left and above Venus. Viewers with good eyes should be able to view seven of Saturn’s moons in the image, including amazing Enceladus just to the left. Take a closer look and you should see icy plumes flying out from Enceladus’s south pole region, which provides the fine, grain-sized icy dust that makes up the E ring.
Saturn’s E-Ring is Visible
Saturn’s E ring appears like a halo surrounding the planet and its inner rings, and the best view of this area is provided by light shining from behind the planet. Astronomers studying Saturn and its rings used enhanced computer programs to improve the contrast and color balance of the pictures. This allowed them to pick out detailed data and evidence which made it possible to trace out the full orbits of smaller moons like Anthe and Methone, for the first time in the history of the human journey to the beginning of space and time. “This mosaic provides a remarkable amount of high-quality data on Saturn’s diffuse rings, revealing all sorts of intriguing structures we are currently trying to understand,” said Matt Hedman, a Cassini participating scientist at the University of Idaho in Moscow. “The E ring shows patterns that likely reflect disturbances from such diverse sources as sunlight and Enceladus’ gravity.”
The astronomers in charge of Cassini usually don’t try to use the instrument to image Earth very often because an unobstructed view of the sun will damage sensitive equipment on the spacecraft. Astronomers had to wait until the sun was hidden behind Saturn, in relation to Cassini, which occurred on July 19, before taking images of Earth and its moon, and the backlit panoramic picture above. “With a long, intricate dance around the Saturn system, Cassini aims to study the Saturn system from as many angles as possible,” said Linda Spilker, Cassini project scientist based at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Beyond showing us the beauty of the Ringed Planet, data like these also improve our understanding of the history of the faint rings around Saturn and the way disks around planets form — clues to how our own solar system formed around the sun.”
Cassini has been exploring Saturn and its local region for nine years to date, and NASA has indicated the spacecraft will continue its mission until at least 2017. We will bring you more images of Saturn and data concerning the planet as long as the human journey to Saturn continues.
Astronomy questions and answers – 2014 is expected to be a banner year for the human journey to the beginning of space and time. This year we are treated to a total eclipse of the Moon for the first time since December 2011. Find a good viewing spot on the night of April 14/15 and watch as the Full Moon falls far into the Earth’s shadow. Skywatchers and astronomers across North America can watch the entire show from the comfort of their favorite dark sky viewing spot. The partial phases of the eclipse will get started around 1:58 a.m. eastern standard time. Watch during the next hour, or so, as the Moon darkens as totality nears. Totality lasts from about 3:06 to 4:25 and the Moon should look orange-red during this period as sunlight filters through the Earth’s atmosphere. The show should finish around 5:33 a.m, with a wrap up of the partial phases.
The Moon once again falls into the Earth’s shadow on the morning of October 8, 2014. The partial phases of this celestial event get started around 5:14 a.m. eastern standard time, with totality occurring at 6:24 a.m. The Moon will spend about an hour immersed in the shadow of Earth, before reappearing like a phantom at 7:24 a.m. Skywatchers and astronomers located in western North America will have the best seat for the show while people on the East Coast will get a partial show.
No total eclipse of the sun in 2014
There will be no total eclipse of the sun during 2014, but on the afternoon of October 23 skywatchers and astronomers across North America will be treated to a partial eclipse of the closest star to Earth. Viewers in the majority of the United States of America should see the Moon block over 40 percent of the Sun’s disk from view while people in the northern states and lower Canada should see the Moon cover over 60 percent. The best view of this partial solar eclipse will be in the far northern regions of Canada, with about 81 percent coverage of the Sun’s disk.
Planet hunters should enjoy the show during 2014
Planet hunters can book a seat for the dramatic appearance of Mars in the sky during spring of 2014. The Red Planet reaches opposition April 8, and will shine at magnitude -1.3 and appear big (15”) and bright when viewed through a telescope. Mighty Jupiter reigns supreme in the sky during the month of January 2014 and will peak early during this month. Saturn will also be spectacular to view both a few months before and after opposition on May 10, 2014, while beautiful and serene Venus will dazzle skywatchers before dawn during late winter and spring.
Meteorite hunters look forward to potentially great 2014
Meteorite hunters can also look forward to a potentially great year of viewing one their favorite celestial bodies. Viewers planning to look at the Perseids during August will have to deal with the light from a Moon which will be almost full, but people watching the Quadrantids during January won’t have to deal with much light from this source. The other expected meteorite showers during 2014 should all be free from interfering light from the moon. All-in-all 2014 should be a memorable year for astronomers and backyard skywatchers taking part in the human journey to the beginning of space and time.
Geophysical data from Messenger illuminates internal structure of Mercury
Astronomy news (December 02, 2013) – NASA’s Messenger Spacecraft answered many questions concerning the innermost planet in the solar system during its two-year mission to Mercury. Messenger took around 80,000 high-definition images of about ninety percent of the surface of Mercury. It also took around 10,600,000 laser ranging shots using the Mercury Laser Altimeter (MLA) in order to map the topography of the planet surface. In addition, astronomers tracked the spacecraft using radio waves in order to gather data on how the spacecraft reacted in the planet’s gravity field.
Mercury’s generates a magnetic field
Astronomers combined the gravity and topographical data from Messenger to learn interesting things about the interior of Mercury. They found the core of Mercury spans about eighty percent of the diameter of the planet, compared to the fifty percent the Earth’s core spans. They also think Mercury has a solid silicate crust and mantle atop a layer of solid iron. Beneath these layers, astronomers believe lies a liquid layer and possibly a solid inner core. Astronomers need this information in order to better understand how the planet generates a magnetic field.
Mercury’s has surface features astronomers at NASA want to take a closer look at
Astronomers looking at Mercury’s surface also found areas with interesting features they want to take a closer look at in the future. They found a ridge in Mercury’s northern region they think formed after the volcanic plains had cooled. They also viewed an altered portion of the Caloris Basin were part of the basin floor is higher than the ridge. This could indicate more recent geophysical activity on the surface of Mercury than first thought.
Astronomers also used the topographical data collected on Mercury to determine the largest height variation on the planet is just 6.2 miles (10 km). This seems unusual since this distance is less than the greatest height variation on both Mars (19 miles [30 km]) and the Moon (12 miles [20 km]).
The Messenger Spacecraft taught us a lot more about Mercury than just the items above. Astronomers announced a lot more interesting things they discovered about Mercury through Messenger recently and you can read about many of these items on the NASA website.
NASA’s Messenger spacecraft continues to study Mercury
Messenger is still in orbit about Mercury taking images and providing astronomers with the data they need to delve even deeper into the mysteries of the innermost planet of our solar system. The spacecraft is presently closer to the surface of Mercury than ever and is taking a closer look at some of the interesting regions and features we mentioned.
Astronomy News – It was a typically slow Friday morning for workers in the Russian industrial city of Chelyabinsk just east of the Ural Mountains. Just after 9 a.m. Russian time, the Sun was hanging just above the horizon to the southeast. The air was cold and still and the sky clear; accept for a few high clouds, and contrails from passing jets.
The quiet morning would explode with the arrival of an unexpected guest. A significant lightening of the sky toward the rising sun was the first hint something was different. Seconds later light exploded in a blinding flash that moved across the sky from right to left. The ground seemed to rumble and rotate in time with naked shadows of buildings, cars, and lampposts.
The blinding glare from the smoking object started to subside as its smoke trail broke into two parallel smokers moving across the southern sky. The sky flared twice more in blinding flashes of intense light, before the objects disappeared over the southwestern horizon.
Shockwave impacts the ground
Three to four minutes after the blinding flash came streaking across the sky, a colossal tremor hit the region shattering windows and causing car alarms to blare and humans to cry and exclaim. Incredibly, no loss of human life would result from the event, although over 1,000 people were treated for related injuries.
NASA has coined the term “superbolide”, for the dazzling bolide that resulted from the passage of a meteorite through the Earth’s atmosphere on February 15, 2013. The meteorite travelled through the atmosphere at a shallow 7 degree descending angle from east to west that passed about 12 miles (20 km) south of Chelyabinsk, Russia. The superbolide occurred when the meteorite was at an altitude of around 76,400 feet (23,300 meters) and moving at a speed of 11.6 miles per second (18.6 km/s).
Force of friction between the atmosphere and meteorite slowed and heated it. The fast movement of the meteorite through the atmosphere also compressed the air in front of it, creating the colossal tremor that shattered windows on the ground. The compression also ionized atoms and molecules, which emitted the blinding flash seen in the Russian sky, when they recombined with the electrons that were stripped from them. This energy also broke up the meteorite and ultimately caused it to explode when the increasing internal pressure exceeded the object’s internal strength.
Astronomy News – Black holes are stellar objects of the most unusual nature and temperament. They’re also something we haven’t witnessed being born during the human journey to the beginning of space and time, until now. NASA astronomers using the Chandra X-ray Observatory to take a look at W49B, a 1,000-year-old supernova remnant, found it to be unlike any they have observed before. In fact, this supernova remnant could have left behind a black hole.
There should be some mass left over in the form of a neutron star
When the most massive suns reach the end of their lives, their central regions collapse and trigger a chain of events that ends in a supernova explosion. Astronomers studying W49B found this supernova remnant was formed when mass from the poles of a 25-solar mass star shot out at a much higher speed than mass shooting from the equator. This is the first supernova remnant with this characteristic they have found in the Milky Way.
Looking for the rabbit hole
Astronomers also couldn’t find the characteristic neutron star they expected to detect within the remnant, which leaves scientists wondering if there’s a black hole lurking somewhere within the cloud. Star scientists are currently studying data concerning W49B, trying to find the telltale evidence they need to indicate the presence of a black hole. Should they find the evidence they’re looking for this will be the first opportunity to study a supernova responsible for creating a young black hole.