OSIRIS-REx, on its way to a December rendezvous with the potentially dangerous asteroid Bennu, successfully made its second course correction last week.
Rendezvous is scheduled for December 3rd. The probed will orbit the asteroid for about six months, then dive in to get a sample in July 2020, returning it to Earth in 2023.
The uncertainty of science: A new analysis by astronomers disputes the conclusion of different astronomers earlier this year that they had found a galaxy that lacked any dark matter.
The original paper from March based its stunning claim of a dark-matter-free galaxy on the way clusters of stars moved through the thin, diffuse galaxy called NGC1052–DF2: They appeared to move at exactly the speed Einstein’s equations of general relativity would predict based on the visible matter (so, slower than they would if the galaxy held dark matter).
This new paper on arXiv suggested otherwise: First, the authors pointed out that NGC1052–DF2 was already discovered way back in 1976 and has previously been referred to by three different names: KKSG04, PGC3097693 and [KKS2000]04.
Then, using those names and then finding all the available data on the galaxy, the researchers argued that the researchers from the March paper simply mismeasured the distance between that galaxy and Earth. This means the galaxy is probably much closer to us than the original researchers thought.
Astronomers calculate the mass of galaxies based on the objects’ brightness and distance. If the galaxy examined in the paper is closer to Earth than previously thought, then its dimness means it’s also much less massive than researchers thought. And at the newly calculated, lighter mass, all the other features of the galaxy make a lot more sense, the researchers in the new paper said. Its globular clusters aren’t moving slowly because they’re in some strange dark matter-desert; instead, they’re moving at the regular speed for a very lightweight galaxy, the arXiv authors said.
To put it bluntly, the astronomers don’t have enough solid data to decide this issue one way or the other. Moreover, the dispute indicates once again that the whole dark matter theory itself is based on very limited data with large margins of error. It might be the best theory we’ve got to explain the data we have, but no good scientist takes it too seriously. We just don’t know enough yet.
The Kepler space telescope is now almost out of fuel, and scientists have ceased science observations to devote the telescope’s last days downloading its last 51 days of data.
The telescope lasted far longer than planned, and discovered thousands of exoplanets. Its archives will be producing new discoveries for decades. And a new exoplanet space telescope, TESS, is already in orbit to take over.
Researchers and local park volunteers in Botswana’s Central Kalahari Game Reserve on July 8 announced the discovery of a fragment from an asteroid that hit the Earth June 2 only eight hours after it was discovered.
“The biggest uncertainty we faced was to determine where exactly the meteorites fell,” says Peter Jenniskens a subject expert of the SETI Institute in California, who traveled to Botswana to assist in the search. He teamed up with Oliver Moses of the University of Botswana’s Okavango Research Institute (ORI), to gather security surveillance videos in Rakops and Maun to get better constraints on the position and altitude of the fireball’s explosion. Team member Tim Cooper of the Astronomical Society of Southern Africa calibrated videos to the south.
After disruption, the asteroid fragments scattered over a wide area, blown by the wind while falling down. Calculations of the landing area were done independently by the NASA-sponsored group headed by Jenniskens, as well as by Esko Lyytinen and Jarmo Moilanen of the Finnish Fireball Network. These calculations were defining the fall area well enough to warrant the deployment of a search expedition.
The first meteorite was found after five days of walking and scouring a landscape of sand, thick tall grass, shrubs and thorn bushes by a team of geoscientists from the Botswana International University of Science and Technology (BUIST), the Botswana Geoscience Institute (BGI) and from ORI, guided by Jenniskens. The Botswana Department of Wildlife and National Parks granted access and deployed their park rangers to provide protection and participate in the search. BUIST student Lesedi Seitshiro was first to spot the stone.
This is only the second time in history that a small asteroid observed in space was recovered following its impact on Earth.
I have amateur astronomer friends who attempted to do this exact thing, here in Tucson. We actually went out one day hunting for a meteorite they had tracked, but were unsuccessful in finding anything. To have had success we would have likely required more search time and a better constraint on the asteroid’s landing zone.
Using data from then space telescope Gaia, astronomers have identified evidence that 8 to 10 billion years ago the Milky Way collided with a dwarf galaxy.
The astronomers propose that around 8 billion to 10 billion years ago, an unknown dwarf galaxy smashed into our own Milky Way. The dwarf did not survive the impact: It quickly fell apart, and the wreckage is now all around us.
“The collision ripped the dwarf to shreds, leaving its stars moving in very radial orbits” that are long and narrow like needles, said Vasily Belokurov of the University of Cambridge and the Center for Computational Astrophysics at the Flatiron Institute in New York City. The stars’ paths take them “very close to the center of our galaxy. This is a telltale sign that the dwarf galaxy came in on a really eccentric orbit and its fate was sealed.”
It is thought that this dwarf galaxy was quite large for a dwarf galaxy.
New data from the space telescope NuSTAR suggests that the giant star Eta Carina, expected to be a supernova sometime in the future, emits cosmic rays, some of which reach the Earth.
The cosmic rays are produced by shock waves resulting from the clash between the intense solar winds of the system’s two stars.
Go to the link to see a truly beautiful image of this star system. You will immediately see that it is a system exploding.
On Monday the Dawn science team released more close-up images of Ceres, taken from Dawn’s final close orbit of the dwarf planet, with the focus of this release Occator Crater and its bright spots.
The current images now show numerous sections of Occator Crater from an altitude of 35 kilometers and with a resolution less than 5 meters per pixel. “The data exceeds all our expectations,” Dr. Andreas Nathues from the MPS, Framing Camera Lead Investigator, says. In the new images, the surface is now ten times better resolved than in the best images from the previous three years.
Impressive avalanches reveal themselves in the new views of the eastern wall of Occator Crater: there are clear signs that material has been recently moving down the slopes; some of it remains stuck halfway. Other images allow a close look at the interplay of bright and dark material in the eastern part of the crater. “We now hope to understand how the bright deposits outside the crater center came about – and what they tell us about Ceres’ interior,” says Nathues. Various analyses of the past years suggest that Ceres has a water-rich crust. Small impacts and landslides regularly expose ice at the surface, which produces a thin exosphere of water vapor.
I have posted some of these images previously, but there are several new ones at the link.
New data suggests that the many meandering canyons on Mars were partly formed by rain.
Although Mars is cold and dry today, channels on its surface look as if running water shaped them, leading researchers to think the planet was warm and wet in the past. But scientists have struggled to determine whether that water fell from the sky as rain or seeped upward from the ground.
To discern the water’s source, Hansjoerg Seybold at the Swiss Federal Institute of Technology (ETH) Zurich and his colleagues analysed the geometry of Martian valley channels. The channels branch off at relatively narrow angles, as do waterways in arid landscapes on Earth, such as the US Southwest. More-humid landscapes with a lot of groundwater — the Amazon rainforest, for example — host river channels that branch at wider angles.
The discovery bolsters the idea that the Martian channels were carved by surface runoff rather than by water percolating from below.
The paper itself is behind a paywall, so it is unclear whether they included in their analysis the consequences of Mars’s lighter gravity. Regardless, this result is intriguing, even if it has a lot of uncertainty.
Scientists have determined, using Cassini data, that there are complex carbon molecules spewing from the tiger stripes on Saturn’s moon Enceladus.
Putting it all together, the scientists concluded that the Cassini spacecraft was encountering dust particles rich in carbon in large, complex “macromolecular structures”. The only place this material could have come from was the interior of Enceladus, from which ice, dust and gas is jetting out in geyser-like plumes. These plumes are fed by vapours escaping from a sub-surface ocean.
“So this is a direct sample of the Enceladus ocean,” Khawaja says.
What exactly the newly discovered organic materials are is open for debate, although Khawaja believes they most likely are made of large numbers of ring-like structures cross-linked by hydrocarbon chains. An important hint comes from the fact that the organic-rich grains don’t contain much water, implying that the materials in them don’t easily mix with water. Khawaja hypothesises that they formed deep inside Enceladus, then rose to the top of its underwater ocean, where they formed a thin film akin to an earthly oil slick.
Just to be very clear, they have not discovered life. What they have found however increases the chances that there is life within Enceladus’s underground ocean.
Based the conclusions [pdf] of an Independent Review Board (IRB), NASA has once again delayed the launch of the James Webb Space Telescope, now set for 2021, while increasing its construction budget from $8 billion to almost $9 billion.
In its report, the IRB found that technical issues, including human errors, have greatly impacted the development schedule.
The agency previously had estimated an earlier launch date, but awaited findings from the IRB before making a final determination and considered data from Webb’s Standing Review Board. The agency established the new launch date estimate [March 30, 2021] to accommodate changes in the schedule due to environmental testing and work performance challenges by Northrop Grumman on the spacecraft’s sunshield and propulsion system. The telescope’s new total lifecycle cost, to support the revised launch date, is estimated at $9.66 billion; its new development cost estimate is $8.8 billion.
It is important to remember that Webb was originally supposed to cost $1 billion, and launch in 2011. It is now a decade behind schedule, with a cost almost ten times higher.
It really does appear like SLS and Webb are in a race to see who can get launched last. And right now, the race is neck and neck.
I should add that if the launch gets delayed much more, NASA will have further problems with the launch rocket. The Ariane 5 rocket, designated as the launch vehicle, is being retired around 2021. Beyond that date there might be problems using one.
The uncertainty of science: New observations of interstellar object Oumuamua suggest that it is a comet, not an asteroid.
[B]y combining data from the NASA/ESA Hubble Space Telescope, the Canada-France-Hawaii Telescope, ESO’s Very Large Telescope and the Gemini South Telescope, an international team of astronomers has found that the object is moving faster than predicted. The measured gain in speed is tiny and `Oumuamua is still slowing down because of the pull of the Sun — just not as fast as predicted by celestial mechanics.
The team, led by Marco Micheli (European Space Agency) explored several scenarios to explain the faster-than-predicted speed of this peculiar interstellar visitor. The most likely explanation is that `Oumuamua is venting material from its surface due to solar heating — a behaviour known as outgassing. The thrust from this ejected material is thought to provide the small but steady push that is sending `Oumuamua hurtling out of the Solar System faster than expected — as of 1 June, it is travelling with about 114 000 kilometres per hour.
Such outgassing is a typical behaviour for comets and contradicts the previous classification of `Oumuamua as an interstellar asteroid. “We think this is a tiny, weird comet,” comments Marco Micheli. “We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets.”
If I was to speculate wildly, I could also wonder if maybe the aliens on board have decided they needed to get the heck out of here as fast as possible, and have fired their thrusters to make that happen.
Cool image time! Dawn, now in its final very close orbit above the surface of Ceres, has released some new images. The image on the right, cropped to post here, was taken from a distance of only 22 miles, and shows a fracture network and some very pronounced cliffs on the wall of Occator Crater. The sunlight is coming from the right. You can also see a bright spot on an east-facing slope with what looks like an apron of lighter avalanche material below it. The flat smooth surface of the floor of this same canyon is likely because it is filled with dust, which has ponded there.
These fractures suggest that the wall of the crater is undergoing a slow motion avalanche, with sections separating off and slowly sagging into the crater below, creating the fractures.
Based on observed data and lab recreations, astronomers have found that much of the galaxy’s interstellar dust is made of grease-like carbon molecules.
Organic matter of different kinds contains carbon, an element considered essential for life. There is though real uncertainty over its abundance, and only half the carbon expected is found between the stars in its pure form. The rest is chemically bound in two main forms, grease-like (aliphatic) and mothball-like (aromatic).
The UNSW / Ege team used a laboratory to create material with the same properties as interstellar dust. They mimicked the process by which organic molecules are synthesised in the outflows of carbon stars, by expanding a carbon-containing plasma into a vacuum at low temperature. The material was collected and then analysed by a combination of techniques. Using magnetic resonance and spectroscopy (splitting light into its constituent wavelengths) they were able to determine how strongly the material absorbed light with a certain infrared wavelength, a marker for aliphatic carbon.
“Combining our lab results with observations from astronomical observatories allows us to measure the amount of aliphatic carbon between us and the stars”, explained Professor Tim Schmidt, from the Australian Research Council Centre of Excellence in Exciton Science in the School of Chemistry at UNSW Sydney.
The researchers found that there are about 100 greasy carbon atoms for every million hydrogen atoms, accounting for between a quarter and a half of the available carbon. In the Milky Way Galaxy, this amounts to about 10 billion trillion trillion tonnes of greasy matter, or enough for 40 trillion trillion trillion packs of butter.
I guarantee that these results have a large margin of error. I also guarantee that they contain a significant element of truth.
Japan’s Hayabusa-2 probe has officially completed its rendezvous with Ryugu, and is now flying about 12 miles above its surface.
Now comes the really hard part, finding landing locations for its MASCOT lander, its three other tiny rovers, and for Hayabusa-2 itself, so it can grab its sample for the return journey.
In one of my weekly posts last month (dated May 14th) delving into the May image release from Mars Reconnaissance Orbiter’s (MRO) high resolution camera, I featured an image of what planetary geologists have labeled chaos terrain, a hummocky chaotic terrain that has no real parallel on Earth but is found in many places on Mars.
This month’s image MRO release included two more fascinating images of this type of terrain. In addition, the Mars Odyssey team today also released its own image of chaos terrain, showing a small part of a region dubbed Margaritifer Chaos. Below, the Mars Odyssey image is on the right, with one of the MRO images to the left. Both have been cropped, with the MRO image also reduced in resolution. The full MRO image shows what the MRO science team labels “possibly early stage chaos” on the rim of a canyon dubbed Shalbatana Vallis.
The Hayabusa-2 science team has released its first image of Ryugu, posted to the right, from a distance of only 25 miles. From the project manager:
The shape of Ryugu is now revealed. From a distance, Ryugu initially appeared round, then gradually turned into a square before becoming a beautiful shape similar to fluorite [known as the ‘firefly stone’ in Japanese]. Now, craters are visible, rocks are visible and the geographical features are seen to vary from place to place. This form of Ryugu is scientifically surprising and also poses a few engineering challenges.
First of all, the rotation axis of the asteroid is perpendicular to the orbit. This fact increases the degrees of freedom for landing and the rover decent operations. On the other hand, there is a peak in the vicinity of the equator and a number of large craters, which makes the selection of the landing points both interesting and difficult. Globally, the asteroid also has a shape like fluorite (or maybe an abacus bead?). This means we expect the direction of the gravitational force on the wide areas of the asteroid surface to not point directly down. We therefore need a detailed investigation of these properties to formulate our future operation plans.
They are going to have to spend some time in orbit to figure out not only where to land, but how to do it. More information on the mission can be found here.
According to one interpretation of a presentation by the Acting head of the Department of Commerce, the Trump administration to going to remove climate change from NOAA’s priorities.
Because of its work on climate science data collection and analysis, [NOAA] has become one of the most important American agencies for making sense of the warming planet. But that focus may shift, according to a slide presentation at a Department of Commerce meeting by Tim Gallaudet, the acting head of the agency.
In the presentation, which included descriptions of the past and present missions for the agency, the past mission listed three items, starting with “to understand and predict changes in climate, weather, oceans and coasts.” In contrast, for the present mission, the word “climate” was gone, and the first line was replaced with “to observe, understand and predict atmospheric and ocean conditions.”
The presentation also included a new emphasis: “To protect lives and property, empower the economy, and support homeland and national security.”
The job of NOAA, if it should have any job at all, should always have been to make observations and collect data. The interpretation and predictions should be left to others. By inserting the issue of climate change into its core priorities the agency’s work was almost guaranteed to become distorted and corrupted by politics. And that is exactly what we have seen.
Expect this change to cause more howls from the left. Expect even more howls when this change forces the Trump administration to start to take a close look at NOAA’s data — something they have not yet done — and discovers the amount of unjustified tampering to it, all aimed at proving the existence of global warming.
The uncertainty of science: Scientists have found that the coldest place on Earth in Antarctica is even colder than previously believed.
Scientists announced in 2013 they had found the lowest temperatures on Earth’s surface: Sensors on several Earth-observing satellites measured temperatures of minus 93 degrees Celsius (minus 135 degrees Fahrenheit) in several spots on the East Antarctic Plateau, a high snowy plateau in central Antarctica that encompasses the South Pole. But the researchers revised that initial study with new data and found the temperatures actually reach minus 98 degrees Celsius (minus 144 degrees Fahrenheit) during the southern polar night, mostly during July and August.
When the researchers first announced they had found the coldest temperatures on Earth five years ago, they determined that persistent clear skies and light winds are required for temperatures to dip this low. But the new study adds a twist to the story: Not only are clear skies necessary, but the air must also be extremely dry, because water vapor traps some heat in the air.
They say this is about as cold as it is possible on the Earth’s surface, as it presently exists.
Hayabusa-2 has moved to within 23 miles of the asteroid Ryugu and is expected to reach its planned 12 mile rendezvous distance on June 27.
No new pictures, though I wouldn’t be surprised if some showed up today or tomorrow.
Hawaii’s Supreme Court is set to review, for the second time, the construction permit for the Thirty Meter Telescope.
Much of the arguments centered around whether it was a conflict of interest for a hearings officer who made a key recommendation in favor of the project to be a member of a Hawaii astronomy center. The state allowed retired judge Riki May Amano to preside over contested-case hearings for the contentious project despite complaints from telescope opponents who decried her paid membership to the Imiloa Astronomy Center.
The Big Island center is connected to the University of Hawaii, which is the permit applicant.
Opponents appealed to the Supreme Court after Amano recommended granting the permit and the state land board approved it. “She should have never presided over the case,” Richard Wurdeman, an attorney representing telescope opponents, told the justices. He noted the center included exhibits about the project planned for the Big Island’s Mauna Kea, Hawaii’s tallest mountain.
The details don’t really matter. Nor will the decision. The protesters will simply find another petty issue if they lose, and will appeal again. Their goal, apparently supported covertly by Hawaii’s Democratic government, is to delay, delay, and delay, until the consortium building TMT is forced to abandon Hawaii.
