Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
A false-color image of NGC 6334 from multiple telescopes. The area is believed to be a hotspot of furious star birth. Credit: S. Willis (CfA+ISU); ESA/Herschel; NASA/JPL-Caltech/ Spitzer; CTIO/NOAO/AURA/NSF
A nebula named after a cat’s paw may be a stealthy spot for a lot of star birth. New observations of NGC 6334 revealed fainter stars than ever before seen, leading astronomers to believe there could be many star babies within the nebula.
“The observations acquired with NEWFIRM allowed us to identify and separate out the large number of contaminating sources, including background galaxies and cool stellar giants in the galactic plane to obtain a more complete census of the newly-formed stars,” stated Lori Allen, an NOAO team member.
Astronomers caught a glimpse of a future star just as it is being born out of the surrounding gas and dust, in a star-forming region similar to the one pictured above. (Spitzer Space Telescope image of DR21 in Infrared) Credit: A. Marston (ESTEC/ESA) et al., JPL, Caltech, NASA
A team led by Sarah Willis, a Ph.D. student at Iowa State University, recorded the stars they saw. Brightness ranged to about equivalent to our sun, to those that are a million times fainter. Then the scientists performed an extrapolation to determine how many lower-mass stars within the region.
“This is analogous to saying that if we observe the adult population in a town, we can estimate how many children live in the town, even if we can’t see them. In this way, the team can derive an estimate of the total number of stars in the region, and the efficiency with which stars are forming,” the NOAO stated.
An ultraviolet view of the Large Magellanic Cloud from Swift's Ultraviolet/Optical Telescope. Almost 1 million ultraviolet sources are visible in the image, which took 5.4 days of cumulative exposure to do. The wavelengths of UV shown in this picture are mostly blocked on Earth's surface. Credit: NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)
Earth’s galactic next-door neighbors shine brighter than ever in new pictures taken by an orbiting telescope, focusing on ultraviolet light that is tricky to image from the surface.
The Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) — the two largest major galaxies near our own, the Milky Way — were imaged in 5.4 days and 1.8 days of cumulative exposure time, respectively. These produced two gorgeous, high-resolution photos in a spot of the light spectrum normally invisible to humans.
“Prior to these images, there were relatively few UV observations of these galaxies, and none at high resolution across such wide areas, so this project fills in a major missing piece of the scientific puzzle,” stated Michael Siegel, lead scientist for Swift’s Ultraviolet/Optical Telescope at the Swift Mission Operations Center at Pennsylvania State University.
Science isn’t interested in these pictures — taken in wavelengths ranging from 1,600 to 3,300 angstroms, mostly blocked in Earth’s atmosphere — because of their pretty face, however. Ultraviolet light pictures let the hottest stars and star-forming areas shine out, while in visible light those hotspots are suppressed.
“With these mosaics, we can study how stars are born and evolve across each galaxy in a single view, something that’s very difficult to accomplish for our own galaxy because of our location inside it,” stated Stefan Immler, an associate research scientist at NASA Goddard Space Flight Center and the lead of the SWIFT guest investigator program.
The Small Magellanic Cloud as seen by Swift’s Ultraviolet/Optical Telescope. This composite of 656 separate pictures has a cumulative exposure time of 1.8 days. Credit: NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)
Although the galaxies are relatively small, they easily shine in our night sky because they’re so close to Earth — 163,000 light-years for the LMC, and 200,000 light years for the SMC.
The LMC is only about 1/10 of the Milky Way’s size, with 1% of the Milky Way’s mass. The punier SMC is half of LMC’s size with only two-thirds of that galaxy’s mass.
Immler revealed the large images — 160 megapixels for the LMC, and 57 megapixels for the SMC — at the American Astronomical Society meeting in Indianapolis on Monday (June 3.)
The sun's newly classified neighborhood -- the Local Arm, as shown in this picture -- is more prominent than previously supposed. Credit: Robert Hurt, IPAC; Bill Saxton, NRAO/AUI/NSF
Some cultures used to say the Earth was the center of the Universe. But in a series of “great demotions,” as astronomer Carl Sagan put it in his book Pale Blue Dot, we found out that we are quite far from the center of anything. The Sun holds the prominent center position in the center of the Solar System, but our star is just average-sized, located in a pedestrian starry suburb — a smaller galactic arm, far from the center of the Milky Way Galaxy.
But perhaps our suburb isn’t as quiet or lowly as we thought. A new model examining the Milky Way’s structure says our “Local Arm” of stars is more prominent than we believed.
“We’ve found there is not a lot of difference between our Local Arm and the other prominent arms of the Milky Way, which is in contrast what astronomers thought before,” said researcher Alberto Sanna, of the Max-Planck Institute for Radio Astronomy, speaking today at the American Astronomical Society’s annual meeting in Indianapolis, Indiana.
Sanna said that one of the main questions in astronomy is how the Milky Way would appear to an observer outside our galaxy.
If you imagine the Milky Way as a rippled cookie, our star is in a neighborhood in between two big ripples (the Sagittarius Arm and the Perseus Arm). Before, we thought the Local Arm (or Orion Arm) was just a small spur between the arms. New research using trigonometric parallax measurements, however, suggests the Local Arm could be a “significant branch” of one of those two arms.
In a few words, our stellar neighborhood is a bigger and brighter one than we thought it was.
Colorado Milky Way. Credit: Michael Underwood
As part of the BeSSeL Survey (Bar and Spiral Structure Legacy Survey) using the Very Long Baseline Array (VLBA), astronomers are able to make more precise measurements of cosmic distances. The VLBA uses a network of 10 telescopes that work together to figure out how far away stars and other objects are.
It’s hard to figure out the distance from the Earth to other stars. Generally, astronomers use a technique called parallax, which measures how much a star moves when we look at it from the Earth.
VLBA telescope locations, courtesy of NRAO/AUI
When our planet is at opposite sites of its orbit — in spring and fall, for example — the apparent location of stellar objects changes slightly.
The more precisely we can measure this change, the better a sense we have of a star’s distance.
The VLBA undertook a search for spots in our galaxy where water and methanol molecules (also known as masers) enhance radio waves — similar to how lasers strengthen light waves. Masers are like stellar lighthouses for radio telescopes, the National Radio Astronomy Observatory stated.
Trigonometric Parallax method determines distance to star or other object by measuring its slight shift in apparent position as seen from opposite ends of Earth’s orbit. CREDIT: Bill Saxton, NRAO/AUI/NSF
Between 2008 and 2012, the VLBA tracked the distances to (and movements of) several masers to higher precision than previously, leading to the new findings.
Will the findings help ease our “inferiority complex” after all those great demotions?
“I would say yes, that’s a nice conclusion to say we are more important,” Sanna told Universe Today. “But more importantly, we are now mapping the Milky Way and discovering how the Milky Might appear to an outside observer. We now know the Local Arm arm is something that an observer from afar would definitely notice!”
Planet HD95086 b is shown at lower left in this picture. Astronomers blocked out the light of the star (center) to image the exoplanet. The blue circle represents the equivalent orbit of Neptune in this star system. Credit: ESO/J. Rameau
We’ve found hundreds of planets outside the solar system, but taking a picture of one is still something quite special. The light of the parent star tends to greatly overwhelm the faint light of the alien planet. (So usually we learn about planets by tracking the effects each planet has on its star, like dimming light when it passes in front or making the star slightly wobble.)
This picture (above) shows HD95086 b, which astronomers believe is one of only about a dozen exoplanets ever imaged. It’s 300 light-years from Earth. The planet candidate is about four to five times the mass of Jupiter and orbiting a very young star that is probably only 10 million to 17 million years old. That’s a baby compared to our own solar system, estimated at 4.5 billion years old.
We still have a lot to learn about this object (and the observations from the Very Large Telescope will need to be confirmed independently), but so far astronomers say they figure that planet formed in the gas and dust surrounding star HD 95086. But the planet is actually very far away from the star now, about twice the distance as the Sun-Neptune orbital span in our own solar system.
The Very Large Telescope (VLT) at ESO’s Cerro Paranal observing site. Credit: European Southern Observatory
“Its current location raises questions about its formation process,” stated team member Anne-Marie Lagrange, who is with the Grenoble Institute of Planetology and Astrophysics in France.
“It either grew by assembling the rocks that form the solid core and then slowly accumulated gas from the environment to form the heavy atmosphere, or started forming from a gaseous clump that arose from gravitational instabilities in the disc.
“Interactions between the planet and the disc itself,” she added, “or with other planets may have also moved the planet from where it was born.”
Astronomers estimate the planet candidate has a surface temperature of 1,292 degrees Fahrenheit (700 degrees Celsius), which could allow water vapor or methane to stick around in the atmosphere. It will take more VLT observations to figure this out, though.
The results from this study will be published in Astrophysical Journal Letters. The paper is also available on prepublishing site Arxiv.
Time Reborn: From the Crisis of Physics to the Future of the Universe is one of those books intended to provoke discussion. Right from the first pages, author Lee Smolin — a Canadian theoretical physicist who also teaches philosophy — puts forward a position: time is real, and not an illusion of the human experience (as other physicists try to argue).
Smolin, in fact, uses that concept of time as a basis for human free will. If time is real, he writes, this is the result: “Novelty is real. We can create, with our imagination, outcomes not computable from knowledge of the present.”
Physics as philosophy. A powerful statement to make in the opening parts of the book. The only challenge is understanding the rest of it.
Smolin advertises his book as open to the general reader who has no background in physics or mathematics, promising that there aren’t even equations to worry about. He also breaks up the involved explanations with wry observations of fatherhood, or by bringing up anecdotes from his past.
Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time. Image credit: NASA
It works, but you need to be patient. Theoretical physics is so far outside of the everyday that at times it took me (with education focusing on journalism and space policy, admittedly) two or three readings of the same passage to understand what was going on.
But as I took my time, a whole world opened up to me.
I found myself understanding more about Einstein’s special and general relativity than I did in readings during high school and university. The book also made me think differently about cosmology (the nature of the universe), especially in relation to biological laws.
While the book is enjoyable, it is probably best not to read it in isolation as it is a positional one — a book that gathers information scientifically and analytically, to be sure, but one that does not have a neutral point of view to the conclusions.
We’d recommend picking up other books such as the classic A Brief History of Time (by physicist Stephen Hawking) to learn more about the universe, and how other scientists see time work.
GRAIL mission in Lunar Orbit. Artist concept of twin GRAIL spacecraft flying in tandem orbits around the moon to measure its gravity field in unprecedented detail. Credit: NASA/JPL
The moon’s gravity has been a headache ever since the Apollo era. Areas of “mass concentration” or mascons, discovered in 1968, affected spacecraft orbits and made landing on Earth’s neighbor a tricky challenge.
The phenomenon has puzzled scientists, but new data shows that mascons might have come to be after asteroids or comets hit the moon a long time ago.
For nine months last year, until their mission ended with a deliberate crash on a moon mountain, twin washing-machine sized spacecraft Ebb and Flow circled the planet. Their work was known as the GRAIL mission (also known as Gravity Recovery and Interior Laboratory.) As they orbited together, gravity changes in the moon below them slightly changed their distances to each other — sometimes closer, sometimes further.
This allowed scientists to map out the mascons to high precision once they combined that information with computer models of big asteroid impacts as well as how craters on the moon evolved.
Craters on the Moon. Image credit: NASA
Mascons, which are invisible on the surface but appear in gravity maps as a sort of bulls-eye, arise “as a natural consequence of crater excavation, collapse and cooling following an impact,” NASA stated.
The center of the bulls-eye has stronger gravity, with a ring of weaker gravity surrounding the bulls-eye, and then another ring of strong gravity surrounding the bulls-eye and inner ring.
“GRAIL data confirm that lunar mascons were generated when large asteroids or comets impacted the ancient moon, when its interior was much hotter than it is now,” stated Jay Melosh, lead researcher and a GRAIL co-investigator at Purdue University.
“We believe the data from GRAIL show how the moon’s light crust and dense mantle combined with the shock of a large impact to create the distinctive pattern of density anomalies that we recognize as mascons.”
What’s more, researchers expect they’ll be able to apply that understanding to Mercury and Mars, as mascons were also discovered on those terrestrial planets.
The findings appeared in the May 30 edition of Science. You can read the entire article here.
Artist's conception of Landsat 8 (renamed from Landsat Data Continuity Mission). Credit: NASA/ Goddard/Conceptual Image Lab
Landsat 8 officially opened its eyes to Earth yesterday (May 30). Officials are promising the clearest views yet of the four-decade-old Landsat program, and luckily for people who love amazing Earth views, the images Landsat produces are free.
Before talking a bit about Landsat 8, here’s one way you can find the images: go to this website of raw Landsat data from the United States Geological Survey. In the menu tab “Collection”, go down to “Landsat Archive” and select “Landsat 8 OLI.” Then click a location on the map to see if it’s taken a picture of a spot you’re interested in.
Once you’ve selected it, hit “Add Scene”, then click on the scene list at the bottom right of the screen to download the product. (We’d strongly advise consulting the tutorial on that website for more help. You need to register as a user to download the high-resolution images.)
There isn’t much to see there yet, but over the next few months there should be a wealth of pictures to choose from. More spots where Landsat 8 data will appear are listed on this USGS page.
You may better recall Landsat 8 as the Landsat Data Continuity Mission. Launched on Feb. 11, it was first under the operational control of NASA as the agency put the satellite through its paces — placing it into the proper orbit (it circles in a near-polar orbit) and taking some test images of the planet, for example.
Now that the satellite is ready, the USGS has operational control and will add that to more than 40 years of data collected under the Landsat program. The aim, we assure you, is not just for pretty pictures.
An Atlas-V rocket with the Landsat Data Continuity Mission (LDCM) spacecraft onboard is seen as it launches on Monday, Feb. 11, 2013 at Vandenberg Air Force Base, California. Credit: NASA
Long Earth observation programs show changes in the land over time. We can see cities grow, observe forests shrink or deserts expand in response to human activity or climate change, and also gauge the impact of natural disasters. In the past, Landsat pictures have been used to map the impact of the Mount St. Helen’s eruption of 1980, and to respond to oil gas fires set in Kuwait during the Gulf War of 1991.
These are heavyweight satellites. The truck-sized Landsat 8 weighs 4,566 lbs (2,071 kg) fully loaded with fuel, excluding the weight of the instruments. Its operational land imager can take pictures in nine spectral bands, which is important because certain types of vegetation or land features show up better in different light spectra. (One application is to monitor the health of certain kind of plants in farmer fields, for example.) It also has two thermal infrared sensor bands that will show the heat signature of Earthly features.
For Landsat, officials needed to launch this satellite because its predecessor (Landsat 7)’s operational lifetime is in overtime. Should the satellite have failed before Landsat 8 arrived, 41 years of continuous Earth observations under the same program would have ceased.
Landsat 8 will circle the globe 14 times daily, will repeat its ground track every 16 days, and is expected to do this for at least five years. Check out this USGS feature story for more on how it will contribute to Earth observation.
Timeline showing lifespans of the Landsat satellites. Credit: NASA
An artist's conception of an asteroid collision, in the belt between Mars and Jupiter. Credit: NASA/JPL-Caltech
In perhaps the neatest astronomical application of geneology yet, astronomers found 28 “hidden” families of asteroids that could eventually show them how some rocks get into orbits that skirt the Earth’s path in space.
From scanning millions of snapshots of asteroid heat signatures in the infrared, these groups popped out in an all-sky survey of asteroids undertaken by NASA’s orbiting Wide-Field Infrared Survey Explorer. This survey took place in the belt of asteroids between Mars and Jupiter, where most near-Earth objects (NEOs) come from.
NEOs, to back up for a second, are asteroids and comets that approach Earth’s orbit from within 28 million miles (45 million kilometers). Sometimes, a gravitational push can send a previously unthreatening rock closer to the planet’s direction. The dinosaurs’ extinction roughly 65 million years ago, for example, is widely attributed to a massive rock collision on Earth.
Artist concept of the asteroid belt between Mars and Jupiter. Credit: NASA
There are about 600,000 known asteroids between Mars and Jupiter, and the survey looked at about 120,000 of them. Astronomers then attempted to group some of them into “families”, which are best determined by the mineral composition of an asteroid and how much light it reflects.
While it’s hard to measure reflectivity in visible light — a big, dark asteroid reflects a similar amount of light as a small shiny one — infrared observations are harder to fool. Bigger objects give off more heat.
This allowed astronomers to reclassify some previously studied asteroids (which were previously grouped by their orbits), and come up with 28 new families.
“This will help us trace the NEOs back to their sources and understand how some of them have migrated to orbits hazardous to the Earth,” stated Lindley Johnson, NASA’s program executive for the Near-Earth Object Observation Program.
This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). Image credit: NASA/JPL-Caltech
The astronomers next hope to study these different families to figure out their parent bodies. Astronomers believe that many asteroids we see today broke off from something much larger, most likely through a collision at some point in the past.
While Earthlings will be most interested in how NEOs came from these larger bodies and threaten the planet today, astronomers are also interested in learning how the asteroid belt formed and why the rocks did not coalesce into a planet.
The prevailing theory today says that was due to influences from giant Jupiter’s strong gravity, which to this day pulls many incoming comets and asteroids into different orbits if they swing too close. (Just look at what happened to Shoemaker-Levy 9 in 1994, for example.)
Artist’s rendering of the environment around the supermassive black hole at the center of Mrk 231. The broad outflow seen in the Gemini data is shown as the fan-shaped wedge at the top of the accretion disk around the black hole, in side view. A similar outflow is probably present under the disk as well. The total amount of material entrained in the broad flow is at least 400 times the mass of the sun per year. Credit: Gemini Observatory/AURA, artwork by Lynette Cook
Right now, as you read this article, it’s quite possible that the ultra-huge black hole at the center of our galaxy is feasting on asteroids or supercooked gas.
We’ve seen these supermassive black holes in other spots in the universe, too: merging together, for example. They’re huge heavyweights, typically ranging between hundreds of thousands to billions of times the mass of the Sun. But we also know, paradoxically, that mini supermassive black holes exist.
So while we’ve observed the gravitational effects of these monsters, a University of Alberta researcher today (May 30) is going to outline the big question: how the heck some of them got so massive. For now, no one knows for sure, but scientists are naturally taking a stab at trying to figure this out.
Maybe they were your ordinary stellar black holes, just three to 100 times the mass of the sun, that underwent a growth spurt. There’s a sticking point with that theory, though: “To do this, the black holes would have to gorge excessively, at rates that require new physics,” stated the Canadian Astronomical Society.
Illustration of Cygnus X-1, a stellar-mass black hole located 6070 ly away. (NASA/CXC/M.Weiss)
“We might also expect to see some black holes that are intermediate in mass between stellar-mass and supermassive black holes in our nearby universe,” the society added, “like a band that is consistently releasing albums, but never making it truly big.”
Anyway, Jeanette Gladstone (a postdoctoral researcher) will make a presentation at CASCA’s annual meeting in Vancouver today outlining some ideas. Gladstone, by the way, focuses on X-rays (from black holes) in her work. Here’s what she said on her research page:
HLX-1 in the periphery of the edge-on spiral galaxy ESO 243-49. Credit: Heidi Sagerud.
“I am currently trying to understand a strange group of curiously bright X-ray binaries. These ultraluminous X-ray sources emit too much X-ray radiation to be explained by standard accretion [of] only a regular stellar mass black hole,” she wrote.
“So I use various parts of the electromagnetic spectrum to try and understand what makes them appear so bright. More recently I have started looking at the very brightest of these sources, a group of objects that have recently become a class in their own right. These are the hyperluminous X-ray sources.”
For context, here’s more info on a hyperluminous X-ray source (and its black hole) in spiral galaxy ESO 234-9, as studied by the Hubble Space Telescope and the Swift X-Ray Telescope.
Astronomers were pretty excited with this 2012 work: “For the first time, we have evidence on the environment, and thus the origin, of this middle-weight black hole,” said Mathieu Servillat, a member of the Harvard-Smithsonian Center for Astrophysics research team, at the time.
The system the European Space Agency is using to aim for pinpoint landings on nearby moons and planets. Credit: ESA
Mission planners really hate it when space robots land off course. We’re certainly improving the odds of success these days (remember Mars Curiosity’s seven minutes of terror?), but one space agency has a fancy simulator up its sleeve that could make landings even more precise.
Shown above, this software and hardware (tested at the European Space Agency) so impressed French aerospace center ONERA that officials recently gave the lead researcher an award for the work.
“If I’m a tourist in Paris, I might look for directions to famous landmarks such as the Eiffel Tower, the Arc de Triomphe or Notre Dame cathedral to help find my position on a map,” stated Jeff Delaune, the Ph.D. student performing the research.
“If the same process is repeated from space with enough surface landmarks seen by a camera, the eye of the spacecraft, it can then pretty accurately identify where it is by automatically comparing the visual information to maps we have onboard in the computer.”
ESA’s SMART-1 mission took this collection of lunar pictures around the south pole, a possible landing target for future missions. Credit: ESA
Because landmarks close-up can look really different from far away, this system has a method to try and get around that problem.
The so-called ‘Landing with Inertial and Optical Navigation’ (LION) system takes the real-time images generated by the spacecraft’s camera and compares it to maps from previous missions, as well as 3-D digital models of the surface.
LION can take into account the relative size of every point it sees, whether it’s a huge crater or a tiny boulder.
At ESA’s control hardware laboratory in Noordwijk, the Netherlands, officials tested the system with a high-res map of the moon.
Though this is just a test and there is still a ways to go before this system is space-ready, ESA said simulated positional accuracy was better than 164 feet at 1.86 miles in altitude (or 50 meters at three kilometers in altitude.)
Oh, and while it’s only been tested with simulated moon terrain so far, it’s possible the same system could help a robot land on an asteroid, or Mars, ESA adds.
No word on when the system will first hitch an interplanetary ride, but Delaune is working to apply the research to terrestrial matters such as unmanned aerial vehicles.
