Astronomers have found that tiny, round, dark clouds called globulettes have the right characteristics to form free-floating planets. The graph shows the spectrum of one of the globulettes taken at the 20-metre telescope at Onsala Space Observatory. Radio waves from molecules of carbon monoxide (13CO) give information on the mass and structure of these clouds. ESO/M. Mäkelä.
Free-floating rogue planets are intriguing objects. These planet-sized bodies adrift in interstellar space were predicted to exist in 1998, and since 2011 several orphan worlds have finally been detected. The leading theory on how these nomadic planets came to exist is that they were they ejected from their parent star system. But new research shows that there are places in interstellar space that might have the right conditions to form planets — with no parent star required.
Polar mesospheric clouds shine over a midnight sunrise above Alaska on August 4, 2013 (NASA)
Looking for a new desktop background? This might do nicely: a photo of noctilucent “night-shining” clouds seen above a midnight Sun over Alaska, taken from the ISS as it passed over the Aleutian Islands just after midnight local time on Sunday, August 4.
When this photo was taken Space Station was at the “top of the orbit” — 51.6 ºN, the northernmost latitude that it reaches during its travels around the planet.
According to the NASA Earth Observatory site, “some astronauts say these wispy, iridescent clouds are the most beautiful phenomena they see from orbit.” So just what are they? Read on…
Found about 83 km (51 miles) up, noctilucent clouds (also called polar mesospheric clouds, or PMCs) are the highest cloud formations in Earth’s atmosphere. They form when there is just enough water vapor present to freeze into ice crystals. The icy clouds are illuminated by the Sun when it’s just below the horizon, after darkness has fallen or just before sunrise, giving them their eponymous property.
NLCs seen in the southern hemisphere in Jan. 2010 (NASA)
Noctilucent clouds have also been associated with rocket launches, space shuttle re-entries, and meteoroids, due to the added injection of water vapor and upper-atmospheric disturbances associated with each. Also, for some reason this year the clouds appeared a week early.
Some data suggest that these clouds are becoming brighter and appearing at lower latitudes, perhaps as an effect of global warming putting more greenhouse gases like methane into the atmosphere.
“When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor,” said James Russell, the principal investigator of NASA’s Aeronomy of Ice in the Mesosphere (AIM) project and a professor at Hampton University. “This extra water vapor is then available to grow ice crystals for NLCs.”
A comparison of noctilucent cloud formation from 2012 and 2013 has been compiled using data from the AIM spacecraft. You can see the sequence here.
And for an incredible motion sequence of noctilucent clouds — taken from down on the ground — check out the time-lapse video below by Maciej Winiarczyk, coincidentally made at around the same time as the ISS photo above:
(The video was featured as the Astronomy Picture of the Day (APOD) for August 19, 2013.)
A DVD bound for Mars... (Courtesy of Lockheed Martin/LASP).
Fans of Mars and spaceflight waxed poetic as the haiku selected to travel to Mars aboard the MAVEN spacecraft were announced earlier this month.
The contest received 12,530 valid entries from May 1st through the contest cutoff date of July 1st. Students learned about Mars, planetary exploration and the MAVEN mission as they composed haiku ranging from the personal to the insightful to the hilarious.
“The contest has resonated with people in ways that I never imagined! Both new and accomplished poets wrote poetry to reflect their views of Earth and Mars, their feelings about space exploration, their loss of loved ones who have passed on, and their sense of humor,” said Stephanie Renfrow, MAVEN Education & Public Outreach & Going to Mars campaign lead.
A total of 39,100 votes were cast in the contest; all entries receiving more than 2 votes (1,100 in all) will be carried on a DVD affixed to the MAVEN spacecraft bound for Martian orbit.
Five poems received more than a thousand votes. Among these were such notables as that of one 8th grader from Denver Colorado, who wrote;
Phobos & Deimos
Moons orbiting around Mars
Snared by Gravity
Another notable entry which was among the poems sited for special recognition by the MAVEN team was that of Allison Swets of Michigan;
My body can’t walk
My mouth can’t make words but I
Soar to Mars today
377 artwork entries were also selected to fly aboard MAVEN as well.
Didn’t get picked? There’s still time to send your name aboard MAVEN along with thousands that have already been submitted. You’ve got until September 10!
Part of NASA’s discontinued Scout-class of missions, the Mars Atmosphere and Volatile EvolutioN mission, or MAVEN, is due to launch out of Cape Canaveral on November 18th, 2013. Selected in 2008, MAVEN has a target cost of less than $500 million dollars US, not including launch carrier services atop an Atlas V rocket in a 401 flight configuration.
The Phoenix Lander was another notable Scout-class mission that was extremely successful, concluding in 2008.
Principal investigator for MAVEN is the University of Boulder at Colorado’s Bruce Jakosky of the Laboratory for Atmospheric and Space Physics (LASP).
The use of poetry to gain public interest in the mission is appropriate, as MAVEN seeks to solve the riddle that is the Martian atmosphere. How did Mars lose its atmosphere over time? What role does the solar wind play in stripping it away? And what is the possible source of that anomalous methane detected by Mars Global Surveyor from 1999 to 2004?
MAVEN is based on the design of the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft. It will carrying an armada of instruments, including a Neutral Gas & Ion Mass Spectrometer, a Particle and Field Package with several analyzers, and a Remote Sensing Package built by LASP.
MAVEN just arrived at the Kennedy Space Center earlier this month for launch processing and mating to its launch vehicle. Launch will be out of Cape Canaveral Air Force Station on November 18th with a 2 hour window starting at 1:47 PM EST/ 18:47 UT.
MAVEN spacecraft at a Lockheed Martin clean room near Denver, Colo. (Credit: Lockheed Martin).
Assuming that MAVEN launches at the beginning of its 20 day window, it will reach Mars for an orbital insertion on September 22, 2014. MAVEN will orbit the Red Planet in an elliptical 150 kilometre by 6,200 kilometre orbit, joining the Mars Reconnaissance Orbiter, the European Space Agencies’ Mars Express and the aging Mars Odyssey orbiter, which has been surveying Mars since 2001.
The window for an optimal launch to Mars using a minimal amount of fuel opens every 24 to 26 months. During the last window of opportunity in 2011, the successful Mars Curiosity rover and the ill-fated Russian mission Phobos-Grunt sought to make the trip.
This time around, MAVEN will be joined by India’s Mars Orbiter Mission, launching from the Satish Dhawan Space Center on October 21st. If successful, the Indian Space Research Organization (ISRO) will join Russia, ESA & NASA in nations that have successfully launched missions to Mars.
This window comes approximately six months before Martian opposition, which next occurs on April 8th, 2014. In 2016, ESA’s ExoMars Mars Orbiter and NASA’s InSight Lander will head to Mars. And 2018 may see the joint ESA/NASA ExoMars rover and… if we’re lucky, Dennis Tito’s proposed crewed Mars 2018 flyby.
Interestingly, MAVEN also arrives in Martian orbit just a month before the close 123,000 kilometre passage of comet C/2013 A1 Siding Spring, although as of this time, there’s no word if it will carry out any observations of the comet.
These launches will also represent the first planetary missions to depart Earth since 2011. You can follow the mission as @MAVEN2Mars on Twitter. We’ll also be attending the MAVEN Conference and Workshop this weekend in Boulder and tweeting our adventures (wi-fi willing) as @Astroguyz. We also plan on attending the November launch in person as well!
And in the end, it was perhaps for the good of all mankind that our own rule-breaking (but pithy) Mars haiku didn’t get selected:
Rider of the Martian Atmosphere
Taunting Bradbury’s golden-bee armed Martians
While dodging the Great Galactic Ghoul
Hey, never let it be said that science writers make great poets!
Hi-res targeted MESSENGER image of the interior of Tyagaraja crater (north is to the right).
Here’s a rather interesting view from orbit around the innermost planet: Mercury’s Tyagaraja crater, the interior of which is seen here in an oblique-angled image acquired by the MESSENGER spacecraft on November 12, 2011 (and released August 16, 2013.)
This view looks west across the northern portion of the 97-kilometer (60-mile) -wide crater, and shows some of its large central peaks, terraced walls, and bright erosion features called hollows that are spread across a wide swath of its interior.
First seen by MESSENGER in 2011, hollows are thought to indicate an erosion process unique to Mercury because of its composition and close proximity to the Sun. The lack of craters within hollows seems to indicate that they are relatively young features… in fact, they may be part of a process that continues today.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury’s surface at resolutions much higher than the 200-meter/pixel morphology base map.
Enhanced-color image of Tyagaraja crater acquired on Sept. 29, 2011. Its large hollow field is highlighted.
Tyagaraja is named after Kakarla Tyagabrahmam, an 18th-century composer of classical Indian Carnatic music.
Up until 20 years ago, the only planets astronomers were aware of were within our Solar System. They assumed others were out there, but none had ever been detected.
Today we know of almost a thousand planets orbiting other stars. They come in a wide variety of sizes. Some are smaller than Earth, and others are more massive than Jupiter. Some are found around solitary stars, while others are located in multiple star systems. In those systems, there can be individual or even multiple planets in orbit. In fact, recent surveys suggest there are planets orbiting every single star in the Milky Way.
So, what methods do astronomers use to find these “extrasolar planets”?
The first extrasolar planet was discovered in 1991.
It was found orbiting a pulsar, a dead star that rotates rapidly, firing out bursts of radiation on an eerily precise interval. As the planets orbit the pulsar, they pull it back and forth with their gravity. This slightly changes the wavelength of the radiation bursts streaming from the exotic star. Astronomers were able to measure these changes, and calculate the orbits of multiple planets.
Radial Velocity Method Extrasolar Planets Far Across GalaxyThe golden age of extrasolar planet discovery began in 1995 when a team from the University of Geneva discovered a planet orbiting the nearby star 51 Pegasi. Astronomers used spectroscopy to break up the light to reveal the elements in its stellar atmosphere. They carefully measured how the wavelengths of light were Doppler shifted over time, and used a technique known as the radial velocity method. They calculated the star’s average motion, and discovered slight variations, as if something was yanking the star towards and away from us.
That something, was a planet.
In fact, this planet was unlike anything we have in the Solar System. 51 Pegasi B has about half the mass of Jupiter and it orbits much closer to its parent star. Closer even, than Mercury to the Sun.
Until this discovery, astronomers didn’t think it was possible for planets to orbit this close, and have had to revise their theories on planetary formation. Many Hot Jupiter planets have been discovered since, some in even more extreme environments.
Gravitational Microlensing Gravitational microlensing method requires that you have two stars that lie on a straight line in relation to us here on Earth. Then the light from the background star is amplified by the gravity of the foreground star, which thus acts as a magnifying glass.Another method astronomers use to find planets is called gravitational microlensing. It works by carefully measuring the brightness of one star as it passes in front of another. The foreground star acts like a lens, focusing the light with its gravity and causing the star to brighten for a few hours. If the foreground star has planets, these will create a telltale spike in the light signature coming from the event.
Amateur astronomers around the world participate in microlensing studies, imaging stars quickly when an event is announced.
Transit Method Of course clouds are no issue if you’re watching the Transit of Venus from the ISS or the Hinode spacecraft. Compare this Hinode Transit image published on APOD on June 9 and enhanced by Marco Di Lorenzo,
The most successful way of finding planets is the transit method.
This is where telescopes measure the total amount of light coming from a star, and detect a slight variation in brightness as a planet passes in front.
Using this technique, NASA’s Kepler Mission has turned up thousands of candidate planets. Including some less massive than Earth, and others in the star’s habitable zone.
From the Kepler data, It’s just a matter of time before the holy grail of planets is uncovered… an Earth-sized world, orbiting a Sun-like star within the habitable zone.
All of these techniques are limited as they require the planets to be orbiting directly between us and their star. If the planets orbit above or below this plane, we just can’t detect them.
Coronographs New Worlds ImagerThere is another method in the works that would unleash the discovery of extrasolar planets, coronographs.
Imagine if you could block all the light from the star, and only see the planets in orbit. This technique has been used for observing the Sun’s atmosphere, but it requires much more precision to see distant stars.
One idea is to position a sunflower-shaped starshade in space, 125,000 km away from the observing telescope. This shade would just cover the star, dimming it by a factor of 10-billion. Light from the planets would leak around the edges.
A sophisticated instrument could even study the atmospheres of these planets, and possibly provide us with evidence of life.
We’re at an exciting time in the field of extrasolar planet research, and trust me, these clever astronomers are just getting started.
The star Alnitak and Flame Nebula in Orion. Credit and copyright: César Cantú.
Astrophotographer César Cantú from Mexico captured this beautiful view of the star Alnitak and Flame Nebula, both in the constellation Orion. Alnitak is the southern star in Orion’s belt, and is an extremely hot star, with a temperature of 29,500 ± 1000 K. It shines brilliantly, and is about 10,000 times more luminous than the Sun. This star also makes the Flame Nebula appear to be blazing, too. Wind and radiation from Alnitak blasts away electrons from the gas in the Flame nebula, causing it to become ionized and glow in visible light.
This gorgeous view was captured on August 11, 2013.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
Horseshoe-shaped lateral moraines at the margin of the Penny Ice Cap on Baffin Island, Nunavut, Canada. Lateral moraines are accumulations of debris along the sides of a glacier formed by material falling from the valley wall. Credit: NASA / Michael Studinger
Enjoy this tour of the Arctic and Greenland, courtesy of the pilots of IceBridge, a six-year NASA mission to survey the ice at both of Earth’s poles. These views come from NASA’s P-3B aircraft, and the video is a selection of some of the best footage from the forward and nadir cameras mounted to the aircraft taken during IceBridge’s spring deployment over Greenland and the Arctic Ocean.
This airborne mission is collecting radar, laser altimetry, and other data on the changing ice sheets, glaciers, and sea ice of the Arctic and Antarctic. It is the largest airborne survey of Earth’s polar ice ever flown, and it will provide an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice. These flights will provide a yearly, multi-instrument look at the behavior of the rapidly changing features of the Greenland and Antarctic ice.
Data collected during IceBridge will help scientists bridge the gap in polar observations between NASA’s Ice, Cloud and Land Elevation Satellite (ICESat) — in orbit since 2003 — and ICESat-2, planned for late 2015. ICESat stopped collecting science data in 2009, making IceBridge critical for ensuring a continuous series of observations.
Neptune and its large moon Triton as seen by Voyager 2 on August 28th, 1989. (Credit: NASA).
If you do your own stargazing or participate in our Sunday night Virtual Star Parties, you’ve probably noticed we’re starting to lose planetary targets in the night-time sky. August and September of this year sees Venus and Saturn to the west at dusk, with the planets Mars and Jupiter adorning the eastern dawn sky just hours before sunrise.
That means there is now a good span of the night that none of the classic naked eye planets are above the horizon. But the good news is, with a little persistence, YOU can spy the outermost planet in our solar system in the coming weeks: the elusive Neptune. (Sorry, Pluto!)
A wide field view of Aquarius, with Neptune’s present position marked for late August/early September. (Created by the author in Stellarium; click on all star charts to enlarge).
The planet Neptune reaches opposition late this month in the constellation Aquarius on August 27th at 01:00 UT (9:00 PM EDT on the 26th). This means that it will rise to the east as the Sun sets to the west and will remain above the local horizon for the entire night.
If you’ve never caught sight of Neptune, these next few weeks are a great time to try. The Moon passes 6° north of the planet’s location this week on August 21st, just 10 hours after reaching Full.
Neptune on the night of Opposition using a 4.4 degree field of view. Magnitudes for nearby guide stars are given in red. (Created by the author using Stellarium).
Shining at magnitude +7.8, Neptune is an easy catch with binoculars from a dark sky site. Even in a large telescope, Neptune appears as a tiny blue dot, almost looking like a dim planetary nebula that refuses to come to a sharp focus. Visually, Neptune is only 2.3” across at opposition; you could stack 782 Neptunes across the breadth of the Full Moon!
It’s sobering to think that Neptune only just returned in 2011 to the position of its original discovery back in 1846. The calculation of Neptune’s position by Urbain Le Verrier was a triumph for Newtonian mechanics, a moment where the science of astronomy began to demonstrate its predictive power.
Astronomers knew of the existence of an unseen body due to the perturbations of the planet Uranus, which was discovered surreptitiously by William Herschel 65 years earlier. Using Le Verrier’s calculations, Johann Galle and Heinrich d’Arrest spied the planet on the night of September 23rd, 1846 using the Berlin observatory’s 9.6” refractor. Neptune was within a degree of the position described in Le Verrier’s prediction.
Neptune orbits the Sun once every 164.8 years, and comes back into opposition once every successive calendar year about 2 days later than the last. Those observers of yore were lucky that Neptune and Uranus experienced a close and undocumented conjunction in 1821; otherwise, Neptune may have gone undetected for a much longer span of time. And ironically, Galileo sketched the motion of Neptune near Jupiter in 1612 and 1613, but failed to identify it as a planet!
The motion of Neptune through Aquarius through late August into September. (Graphic created by author; courtesy of Starry Night Education).
Neptune descended through the ecliptic in 2003 and won’t reach its southernmost point below it until 2045. This month, Neptune lies 1.5 degrees west of the +4.8 magnitude double star Sigma Aquarii. Neptune passes less than 4’ from +7.5 magnitude star HIP 110439 on September 9th as it continues towards eastern quadrature on November 24th.
Corkscrew chart for the elongations of Triton through early September. (Courtesy of Ed Kotapish; created using NASA/PDS Rings Node).
Up for a challenge? Neptune also has a large moon named Triton that is just within range of a moderate (8” in aperture or larger) telescope. Shining at magnitude +13.4, Triton is similar in brightness to Pluto and is 100 times fainter than Neptune. In fact, there’s some thought that Pluto may turn out to be similar to Triton in appearance when New Horizons gets a close-up look at it in July 2015.
Triton never strays more than 18” from Neptune during eastern or western elongations. This presents the best time to cross the moon off your astronomical “life list…” experienced amateurs have even managed to image Triton!
The moons of Neptune and Uranus imaged by Rolf Wahl Olsen using a 10″ reflector and a ToUCam Pro. An amazing catch! (Credit & Copyright: Rolf Wahl Olsen, used with permission).
Triton was discovered just 17 days after Neptune by William Lassell using a 24” reflector. Triton is also an oddball among large moons in the solar system in that it’s in a retrograde orbit.
A second moon named Nereid was discovered by Gerard Kuiper in 1949. To date, Neptune has 14 moons, including the recently discovered S/2004 N1 unearthed in Hubble archival data.
Neptune & Triton on the night of August 21st as it reaches greatest elongation. (Graphic created by author. Courtesy of Starry Night Education).
To date, Voyager 2 is the only spacecraft that has studied Neptune and its moons up close. Voyager 2 conducted a flyby of the planet in 1989. A future mission to Neptune would face the same dilemma as New Horizons: a speedy journey would still take nearly a decade to complete, which would rule out an orbital insertion around the planet. (Darn you, orbital mechanics!) In fact, New Horizons just crosses the orbit of Neptune at a distance of 30 astronomical units from the Earth in 2014.
Neptune is about four light hours away from the Earth, a distance that varies less than 20 minutes in light travel time from solar conjunction to opposition. And while Neptune and Triton may not appear like much more than dim dots through a telescope, what you’re seeing is an ice giant 3.8 times the diameter of the Earth, with a large moon 78% the size of our own.
Make sure to cross Neptune and Triton off of your bucket list… and next month, we’ll be able to do the same for the upcoming opposition of Uranus!
A subsurface spacecraft prototype is deliberately slammed into 10 tonnes of ice in a rocket facility. Credit: European Space Agency/YouTube (screenshot)
If you want to get inside a planet or moon fast, the European Space Agency says lobbing a spacecraft at the surface might be a good approach.
This concept may sound like suicide. A recent prototype test, however, shows the spacecraft structure is mostly okay. Next step is figuring out what can survive on the inside.
ESA, like NASA and other agencies, isn’t afraid to test out new landing concepts if they suit better than the traditional ones (which use rockets and/or parachutes to land a spacecraft softly on the surface). Witness the Curiosity rover’s “seven minutes of terror” concept as a successful example.
Imagine that you want to look at water below the surface of Mars, or (like the people in Europa Report) you wish to plumb into the ice of Jupiter’s moon, Europa. One option could be a drill. Another one could be a subsurface spacecraft.
“One benefit over landers and rovers is that penetrators provide access to the subsurface without the need for additional drilling or digging,” ESA stated.
To test this out, engineers put 12 solid-propellant boosters on to a 44-pound (20 kilogram) prototype and fired it at almost the speed of sound at sea level: 1,118 feet a second (341 meters/second). (More technical details on the test).
The 1.5-second test, shown in the video, saw the prototype careening into 10 tonnes of ice at a deceleration of 24,000 times the force of gravity. Astronauts, by contrast, usually only withstand 3-4 g when going into space.
The scuffed and dented spacecraft was retrieved successfully, and now ESA is reviewing how well the internal structure held up in the chaos. They also plan to develop battery and communications systems that could somehow survive intact.
High-speed tests are not only useful for spacecraft landings, but also for meteor simulations.
Most meteors are comet dust striking at the atmosphere at speeds so high, they vaporiz in a blaze of light. This is a meteor from the Leonid shower in 2001. Credit: Bob King
An article in Wired recently covered the progress of the NASA Ames Vertical Gun range in its nearly 50 years of operation.
“Though it’s called a gun, the facility doesn’t look much like any firearm you’ve ever seen,” wrote Adam Mann. “The main chassis is a long metal barrel as thick as a cannon mounted on an enormous red pole that forks at the end into two legs.”
On this warm August evening, three astronomers shared their live view of the night sky for a Virtual Star Party. The Moon was nearly full, but instead of hating it, Mark Behrendt decided to bring it into our view for the evening. We also had fantastic views of several of the famous summer nebulae: the Lagoon, the Swan, Veil, Ring, and Dumbbell Nebula.
Fraser also demonstrated his terrible skills as a space agency director, launching a few virtual rockets in the Kerbal Space Program while we waited for telescopes to update.
We run the Virtual Star Party as a live Google+ Hangout on Air every Sunday night when it gets dark on the West Coast. In the summer, that means 9:00 pm Pacific / 12:00 am Eastern. You can view the show live from the Universe Today YouTube page, or right here on Universe Today; we’ll embed the video on the site right before we begin.
We’re always looking for more astronomers, so if this sounds like something you’d like to participate it, just drop me an email at [email protected].
