Tag: science

Scientists reject discovery of biggest known black hole

9:20 am

The uncertainty of science: In three new papers published this week astronomers have found that the announced discovery in early December of the biggest super-massive black hole ever found, 70 times the mass of the Sun, does not hold up.

In a recent study (a peer-reviewed study published Nov. 27), a team of scientists reported the discovery of the binary system LB-1, which contains a star and, according to the findings, a black hole companion 70 times the mass of our sun. This was major news, a stellar-mass black holes (black holes formed by the gravitational collapse of a star) are typically less than half that massive. But while the study, led by Jifeng Liu, of the National Astronomical Observatory of China (NAOC) of the Chinese Academy of Sciences, was exciting, it was also wrong.

Three new papers came out this week that reexamined the findings from Liu’s study, and these studies say that LB-1’s black hole isn’t actually all that massive.

The new papers find that a closer look at the data finds that it wasn’t doing what the initial researchers thought.

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Maven makes first map of Mars’ high altitude winds

9:11 am

High altitude wind patterns on Mars

Scientists using the Martian orbiter Maven have produced the first global map of the high altitude wind circulation of Mars.

The measurements of winds that were recently mapped above Mars were found at an altitude range of about 140-240 kilometers (85-150 miles) above the planet’s surface.

The wind data has been gathered by the Neutral Gas and Ion Mass Spectrometer (NGIMS). NGIMS’ original purpose was to determine the structure and composition of the Martian atmosphere by measuring in it the amounts of ions (electrically charged particles) and gases. However, although it was not originally designed to do so, in April 2016, the MAVEN team began using NGIMS to observe horizontal winds. Pausing normal collection of data, scientists on Earth programmed the instrument to nod back and forth so that it could detect the direction of winds along its track.

By combining data from many tracks as MAVEN orbits Mars, scientists slowly built up a map of wind behavior. This led to a startling discovery: the wind patterns actually correlated with the Martian topography below.

They have found that even at this high altitude the winds shift around the high volcanoes of the Tharsis Bulge.

To my eye, the wind pattern seen in the image, taken from the video at the link, is remarkably similar to the global wind patterns found on Venus, forming a widening V-pattern moving from east to west. Though the two are vastly different, the similarity is quite intriguing.

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Interacting galaxies

8:42 am

Interacting galaxies
Click for full image.

Astronomers using the 8-meter Gemini Telescope on Mauna Kea today released a new image of the Heron galaxy, showing its interaction with a nearby neighbor.

The new image captures the slow and intimate dance of a pair of galaxies some 160 million light-years distant and reveals the sparkle of subsequent star formation fueled by the pair’s interactions.

The two galaxies, astronomers have concluded, have already “collided” at least once. However, galactic collisions can be a lengthy process of successive gravitational encounters, which over time can morph the galaxies into exotic, yet unrecognizable forms. These galaxies, as in all galactic collisions, are engaged in a ghostly dance as the distances between the stars in each galaxy preclude actual stellar collisions and their overall shapes are deformed only by each galaxy’s gravity.

One byproduct of the turbulence caused by the interaction is the coalescence of hydrogen gas into regions of star formation. In this image, these stellar nurseries are revealed in the form of the reddish clumps scattered in a ring-like fashion in the larger galaxy (and a few in the smaller galaxy). Also visible is a dusty ring that is seen in silhouette against the backdrop of the larger galaxy. A similar ring structure is seen in this previous image from the Gemini Observatory, likely the result of another interacting galactic pair.

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New storm spotted at Jupiter’s south pole

8:31 am

New cyclone at Jupiter's south pole
Click for full image.

New images from Juno have revealed the formation of a new Texas-sized cyclone joining the circle of storms around Jupiter’s south pole.

In the infrared Juno image to the right, the new storm is the small bright cyclone in the lower right.

[D]uring Juno’s 22nd science pass [on November 3], a new, smaller cyclone churned to life and joined the fray. “Data from Juno’s Jovian Infrared Auroral Mapper [JIRAM] instrument indicates we went from a pentagon of cyclones surrounding one at the center to a hexagonal arrangement,” said Alessandro Mura, a Juno co-investigator at the National Institute for Astrophysics in Rome. “This new addition is smaller in stature than its six more established cyclonic brothers: It’s about the size of Texas. Maybe JIRAM data from future flybys will show the cyclone growing to the same size as its neighbors.”

Probing the weather layer down to 30 to 45 miles (50 to 70 kilometers) below Jupiter’s cloud tops, JIRAM captures infrared light emerging from deep inside Jupiter. Its data indicate wind speeds of the new cyclone average 225 mph (362 kph) – comparable to the velocity found in its six more established polar colleagues.

Because of Juno’s orbit we do not get continuous views of the gas giant’s cloud-tops, so we can’t see the moment-by-moment evolution of these storms, which makes it impossible to obtain a full understanding of their formation or disappearance. Even then it will likely take centuries of observations to even begin to get a fuller understanding of the meteorology of Jupiter.

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New Hubble images of Comet 2I/Borisov

12:17 pm

Comet 2I/Borisov taken by Hubble prior to and at its closest approach to Sun
Click for full image.

Scientists today released new images taken by the Hubble Space Telescope of the interstellar object Comet 2I/Borisov. The image on the left was taken prior to the comet’s closest approach to the Sun, while the image on the right was taken during that closest approach. The vertical smeared object to the left in the earlier image is a galaxy that happened to be in the field of view. The blue color of both images is a false color to bring out details.

“Hubble gives us the best upper limit of the size of comet Borisov’s nucleus, which is the really important part of the comet,” said David Jewitt, a UCLA professor of planetary science and astronomy, whose team has captured the best and sharpest look at this first confirmed interstellar comet. “Surprisingly, our Hubble images show that its nucleus is more than 15 times smaller than earlier investigations suggested it might be. Our Hubble images show that the radius is smaller than half-a-kilometer. Knowing the size is potentially useful for beginning to estimate how common such objects may be in the solar system and our galaxy. Borisov is the first known interstellar comet, and we would like to learn how many others there are.”

The first image was taken from a distance of 203 million miles, while the second was taken from 185 million miles. Expect more images in late December, when the comet makes its closest approach to Earth at a distance of 180 million miles.

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OSIRIS-REx team picks primary sample site

12:03 pm

Four candidate landing sites
Click for full image.

The OSIRIS-REx science team has picked the site they have dubbed Nightingale as the primary landing site where they will attempt to obtain a sample from the asteroid Bennu in the summer of 2020. The back-up site is Osprey at the equator.

I have embedded the replay of the NASA live stream of the press event below the fold. The first 21 minutes of the video are an overview of the mission, leading up to the announcement by Dante Lauretta, OSIRIS-REx’s principal investigator. He notes then that the site “does have some hazards” but they chose it for its “scientific value.” While its higher latitude location has some advantages, it also makes it more difficult for landing. The one large boulder there, which Lauretta calls “Mt Doom,” also carries risk for the touch-and-go operations.

The back-up site, Osprey, is on the equator with less hazards, but will present more problems obtaining the tiny-sized particles the sample grab equipment was designed to get.

Not that this matters, but if I have been in a betting pool I would have won, since Nightingale has been my guess for which site they’d pick since early November.
» Read more

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A new map of the water ice on Mars

9:45 am

Annotated water ice map of Mars
Click for full resolution image.

In a new science paper planetary scientists have produced a new global map of the water ice of Mars, based on data from Mars Reconnaissance Orbiter (MRO) and Mars Odyssey.

The image above is a lower resolution version of that map, annotated by me. The black areas are regions covered with a thicker layer of dust, so no good data was obtained. As you go from red to green to blue to purple the ice is thought to be closer to the surface, with the depth as small as an inch in the dark purple areas. The white rectangular represents the region best for human settlement, as it has ice near the surface and is at lower latitudes.

The red box indicates the location in Arcadia Planitia that is SpaceX’s candidate landing zone for Starship. Based on this new water ice map it appears that SpaceX has chosen very well. And the scientists who wrote this paper agree, as noted in the press release: “A large portion of a region called Arcadia Planitia is the most tempting target in the northern hemisphere.”

The map also confirms the existence of the 30 to 60 degree latitude bands where scientists believe a lot of buried glaciers exist. Both bands are both very evident in this new map.

To provide some further context, below is a global map of Mars labeled to show its major geographic features as well as the locations of all previous and upcoming landers/rovers, rearranged to match the water ice map above.
» Read more

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How the Mars2020 rover differs from Curiosity

1:00 pm

A JPL press release today outlines some of the main engineering differences between Curiosity, the rover that has been exploring Gale Crater for the past fifteen years, and Mars2020, the unnamed rover that will be launched in July 2020 to explore Jezero Crater

One of the major the engineering improvements, based on what was learned with Curiosity, are the Mars2020 wheels:

Curiosity has prepared Mars 2020’s team for “off-roading” on the Red Planet. When holes began appearing in the veteran rover’s aluminum wheels, engineers realized that sharp rocks cemented on the Martian surface exert more pressure on the wheels than expected. Careful drive planning, along with a software upgrade, will keep them in shape for the rest of Curiosity’s journey up Mount Sharp.

While Mars 2020’s wheels are made from the same materials, they’re slightly bigger and narrower, with skins that are almost a millimeter thicker. Instead of Curiosity’s chevron-pattern treads, or grousers, Mars 2020 has straighter ones and twice as many per wheel (48 versus 24). Extensive testing in JPL’s Mars Yard has shown these treads better withstand the pressure from sharp rocks but work just as well on sand.

The computer and software has also been upgraded to speed daily operations. In addition, the new rover will have 23 cameras, six more than Curiosity, all of which will be capable of producing color images. And most important, the drill will be larger and will drill cores for obtaining samples that will be stored for possible return by a later mission.

The landing is set for February 18, 2021. If all goes well this rover will be exploring the Martian surface well in to the 2030s.

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Sunspot update Nov 2019: The longest flatline in centuries

5:53 pm

The Sun is now in what appears to be the longest stretch ever recorded, since the 11-year solar sunspot cycle reactivated in the 1700s after the last grand minimum, of sunspot inactivity. This record-setting dearth of practically no sunspots has now stretched to six months in a row.

On December 8 NOAA released its November update of its graph showing the long term sunspot activity of the Sun. As I have done now every month since this webpage began in 2011, I have posted it below, with annotations:

November 2019 sunspot activity
The graph above has been modified to show the predictions of the solar science community for the previous solar maximum. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction, extended in November 2018 four years into the future.

In November the Sun saw two official sunspots (here and here) and one active area that never received an official sunspot number, with two of these three weak events having a polarity linking them to the next solar maximum.
» Read more

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The dark splotches on Mars: Magnets for dust devils

3:38 pm

Olympus Maculae, land of dark splotches

One of the numerous geological mysteries that planetary scientists have discovered among the many high resolution images taken by the various Martian orbiters are a series of dark splotches, ranging in diameter from one to fifteen miles, running in an east-west line on the lower western slopes of the giant volcano Olympus Mons.

Scientists have dubbed this string of splotches Olympus Maculae and, because of their superficial resemblance to the islands of Hawaii, have labeled each splotch, or macula, after those islands, as shown in the overview map above, created by geologist Kirby Runyon of the Applied Physics Lab in Maryland as part of a presentation [pdf] given at a science conference in September 2019.

Prior to the 2018 global dust storm on Mars scientists were not quite sure what caused these dark patches. The data suggested the maculae were less dusty than the surrounding terrain, but why this was so was not clear.

The advent of that storm however gave them a chance to get before and after photos. In October 2018 I found several images in monthly download of new images from the high resolution camera of Mars Reconnaissance Orbiter (MRO) and posted them, making a vain attempt to locate what had changed. As I wrote,

I found that MRO has taken images of this location twice before, in 2007 and in 2009. I spent about fifteen minutes trying to find something that had changed, but was unable to locate anything, other than what look like a few wind-blown streaks probably caused by dust devils. I suspect I do not know what to look for.

I then made some guesses about what caused these splotches, all wrong I have since learned.

Since then more images of these splotches have been downloaded from MRO, all once again indicating that changes have been detected. Below is a sequence of images of the splotch dubbed Ka’ula, the first taken in 2008, the second in 2018 just after the global dust storm, and the third in 2019, one year after the storm. Set side-by-side the changes are more obvious.
» Read more

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Cloud stream on Jupiter

9:21 am

Cloud stream on Jupiter
Click for full image.

Cool image time! The photo to the right, taken by Juno on November 3, was enhanced by citizen scientist Björn Jónsson to bring out the colors. It shows a band of repeating large storms, with tiny white thunderheads popping up within them.

The dark areas at the edges of the swirls are likely not an aspect of the clouds but shadows created because the white swirls sit higher than the surrounding gases.

Sadly the press release does not give us a scale. The image was taken from a distance of 3,200 miles. I suspect each cloud swirl would likely cover much of the Earth.

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OSIRIS-REx completes reconnaissance of four candidate sample sites

10:04 am

Four candidate landing sites
Click for full image.

OSIRIS-REx has completed its high resolution reconnaissance of the four candidate sites on the asteroid Bennu, chosen for possible sample capture during touch-and-go operations planned for the summer of 2020.

In the next few days the science team will decide which of these four sites, shown above, will be the primary and back-up landing locations. The decision however appears challenging, based on the information gathered.

Bennu has also made it a challenge for the mission to identify a site that won’t trigger the spacecraft’s safety mechanisms. During Recon A, the team began cataloguing Bennu’s surface features to create maps for the Natural Feature Tracking (NFT) autonomous navigation system. During the sample collection event, the spacecraft will use NFT to navigate to the asteroid’s surface by comparing the onboard image catalog to the navigation images it will take during descent. In response to Bennu’s extremely rocky surface, the NFT system has been augmented with a new safety feature, which instructs it to wave-off the sampling attempt and back away if it determines the point of contact is near a potentially hazardous surface feature. With Bennu’s building-sized boulders and small target sites, the team realizes that there is a possibility that the spacecraft will wave-off the first time it descends to collect a sample.

Based on the information at the link, plus the presentation by Dante Lauretta, OSIRIS-REx’s principal investigator, given at the asteroid conference I attended in November, I suspect that Nightingale will be primary landing site.

Regardless, it appears the science team has recognized that the landing will difficult, and will likely require multiple attempts before the spacecraft’s navigation system lets it happen.

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First results from Parker released

1:11 pm

Scientists today published four papers outlining the first scientific results obtained during the first two close fly-bys of the Sun by the Parker Solar Probe.

The four papers, now available online from the journal Nature, describe Parker’s unprecedented near-Sun observations through two record-breaking close flybys. They reveal new insights into the processes that drive the solar wind – the constant outflow of hot, ionized gas that streams outward from the Sun and fills up the solar system – and how the solar wind couples with solar rotation. Through these flybys, the mission also has examined the dust of the coronal environment, and spotted particle acceleration events so small that they are undetectable from Earth, which is nearly 93 million miles from the Sun.

During its initial flybys, Parker studied the Sun from a distance of about 15 million miles. That is already closer to the Sun than Mercury, but the spacecraft will get even closer in the future, as it travels at more than 213,000 mph, faster than any previous spacecraft.

Details about the four main takeaways are described at the link. None of the discoveries is earth-shaking but all help scientists better understand the Sun’s inner atmosphere.

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Chang’e-4 and Yutu-2 complete 12th lunar day

12:17 pm

Chinese engineers have put both Chang’e-4 and Yutu-2 into dormant mode after completed their twelve lunar day on the far side of the Moon.

The article from the Chinese state-run press provides very little information, other than telling us that Yutu-2 traveled 345 meters, written in a way to imply that was the distance the rover traveled in this last lunar day. I think that is wrong, however. Based on the distances traversed during previous lunar days, and that the rover had traveled a total of 290 meters at the end of its tenth lunar day, I think this new number is the total distance traveled.

The article also does not say what the consequences will be for these two spacecraft now that the priority of their communications relay has shifted from communications to being a radio telescope.

It could be that the consequences will be minor, considering that both spacecraft are in sleep mode during the lunar nights and for high noon of the lunar day. During those periods the relay satellite could be devoted full time to radio astronomy and have no impact on the lander and rover.

Unfortunately China has not said.

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TESS captures outburst from comet

5:42 pm

Wirtanen outburst

The space telescope TESS, designed to look for exoplanets by imaging one hemisphere of the sky repeatedly over a full year, also successfully captured in those images the full outburst from the comet 46P/Wirtanen that occurred on September 26, 2018.

The animation created from those images is to the right.

According to Farnham, the TESS observations of comet Wirtanen were the first to capture all phases of a natural comet outburst, from beginning to end. He noted that three other previous observations came close to recording the beginning of an outburst event. Observations of a 2007 outburst from comet 17P/Holmes began late, missing several hours of the initial brightening phase of the event. In 2017, observations of an outburst from comet 29P/Schwassmann-Wachmann 1 (SW1) concluded early, due to limitations on pre-scheduled observation time. And, while observations from the UMD-led Deep Impact mission captured an outburst from comet Tempel 1 in unprecedented detail in 2005, the outburst was not natural—created instead by the mission’s impactor module. However, the current observations are the first to capture the dissipation phase in its entirety, Farnham said.

Although Wirtanen came closest to Earth on December 16, 2018, the outburst occurred earlier in its approach, beginning on September 26, 2018. The initial brightening of the outburst occurred in two distinct phases, with an hour-long flash followed by a more gradual second stage that continued to grow brighter for another 8 hours. This second stage was likely caused by the gradual spreading of comet dust from the outburst, which causes the dust cloud to reflect more sunlight overall. After reaching peak brightness, the comet faded gradually over a period of more than two weeks. Because TESS takes detailed, composite images every 30 minutes, the team was able to view each phase in exquisite detail.

The data from TESS is likely going to overwhelm the astronomy community for years.

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New analysis suggests dark energy might not be necessary

5:29 pm

The uncertainty of science: A new peer-reviewed paper in a major astronomy science journal suggests that dark energy might not actually exist, and that the evidence for it might simply be because the original data was biased by the Milky Way’s own movement.

What [the scientists in this new paper] found is that the best fit to the data is that the redshift of supernovae is not the same in all directions, but that it depends on the direction. This direction is aligned with the direction in which we move through the cosmic microwave background. And – most importantly – you do not need further redshift to explain the observations.

If what they say is correct, then it is unnecessary to postulate dark energy which means that the expansion of the universe might not speed up after all.

Why didn’t Perlmutter and Riess [the discoverers of dark energy] come to this conclusion? They could not, because the supernovae that they looked were skewed in direction. The ones with low redshift were in the direction of the CMB dipole; and high redshift ones away from it. With a skewed sample like this, you can’t tell if the effect you see is the same in all directions.

The link is to a blog post by a physicist in the field, commenting on the new paper. Below the fold I have embedded a video from that same physicist that does a nice job of illustrating what she wrote.

This paper does not disprove dark energy. It instead illustrates the large uncertainties involved, as well as show solid evidence that the present consensus favoring the existence of dark energy should be questioned.

But then, that’s how real science works. When the data is sketchy or thin, with many assumptions, it is essential that everyone, especially the scientists in the field, question the results. We shall see now if the physics community will do this.

Hat tip to reader Mike Nelson.

» Read more

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A crack in the Martian crust

3:39 pm

Crack in the Martian crust
Click for full image.

Cerberus Fossae

The photograph to the right, reduced and cropped to post here, was imaged on October 20, 2019 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a spectacular thousand-foot-deep canyon in the region of Cerberus Fossae, an area of Mars crossed by numerous deep east-west fissures and depressions.

Hidden in the small white box on the eastern end of that canyon are Martian geological features, small and at first glance not that interesting, that are of great significance and the focus of intense research.

The map to the right shows an overview of the region. The yellow cross shows the location of this particular crack.

In my previous post about Cerberus Fossae, I had incorrectly assumed that these cracks and similar lines of pits or depressions were caused by the sinking of surface material into underground lava tubes. While this is possible in some cases, it is not the main cause of these cracks. Instead, they were formed due to the pressure from below caused by the rise of the surrounding giant volcanoes, Elysium Mons to the north and Olympus Mons to the east. That pressure stretched the crust until it cracked in numerous places. In Cerberus Fossae this produced a series of parallel east-west fissures, some more than seven hundred miles long.

The young age of Cerberus Fossae is dramatically illustrated by the wider mosaic below, showing the entire crack.
» Read more

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Hayabusa-2 fires main ion engines for return to Earth

8:20 am

After spending two weeks testing its main ion engines just beyond the gravitational sphere of influence of the asteroid Ryugu, Japanese engineers today initiated full engine operation, beginning the spacecraft’s journey back to Earth.

Hayabusa-2 is expected to return to Earth space in December 2020, where it will release a small capsule containing the two samples it obtained of Ryugu will be released to land on Earth and be recovered. At that point, if Hayabusa-2 is still in good condition it will be available to send to other locations in the solar system.

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Astronomers find record-setting heaviest supermassive black hole

8:05 am

Astronomers have discovered the most massive black hole yet discovered, having a mass 40 billion times the mass of our Sun.

The new data obtained at the USM Wendelstein observatory of the Ludwig-Maximilians-University and with the MUSE instrument at the VLT [Very Large Telescope in Chile] allowed the team to perform a mass estimate based directly on the stellar motions around the core of the galaxy. With a mass of 40 billion solar masses, this is the most massive black hole known today in the local universe. “This is several times larger than expected from indirect measurements, such as the stellar mass or the velocity dispersion of the galaxy,” remarks Roberto Saglia, senior scientist MPE and lecturer at the LMU.

The light profile of the galaxy shows a centre with an extremely low and very diffuse surface brightness, much fainter than in other elliptical galaxies. “The light profile in the inner core is also very flat,” explains USM doctoral student Kianusch Mehrgan, who performed the data analysis. “This means that most of the stars in the centre must have been expelled due to interactions in previous mergers.”

To give some perspective, the mass of the supermassive black hole in the center of the Milky Way, Sagittarius A* (pronounced A-Star), is thought to be about 4.6 million solar masses. This newly discovered supermassive black hole is almost nine thousand times heavier.

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Martian “What the heck?” formations

2:41 pm

What the heck caused these?
Click for full image.

Cool image time! In digging through the new images that come down from the high resolution camera on Mars Reconnaissance Orbiter (MRO), my reaction sometimes is “What the heck caused that?”

That was my reaction when I looked at the image to the right, cropped to post here.

The full image, taken on October 6, 2019, shows the floor of one of the many north-south fissures found in the volcanic Tharsis Bulge west of Valles Marineris and east of Olympus Mons. The fissures are caused when the crust is pushed upward by volcanic pressure, causing the surface to crack.

In this case the mystery is that patch of east-west ridges at the bottom of this somewhat wide fissure. While they might be dunes, they do not resemble dunes, as they have a rigid and somewhat sharp appearance. More puzzling is their somewhat abrupt appearance and disappearance. Except for its northern end, the edges of the patch are so sharply defined. If these were dunes you’d think they’d fade away more gradually.

Could the ridges be a more resistant subsurface feature slowly being revealed as surface material erodes away? Sure, but their orientation is completely opposite to the north-south fissures that dominate this region. One would expect deeper features to reflect that same general orientation. These ridges do not.

This image was dubbed a “Terrain Sample,” which means it was taken not because of any specific research goal, but because the scientists who run MRO’s high resolution camera had a gap in their schedule and needed to take a picture to maintain the camera’s proper temperature. In such cases they often take somewhat random images, not knowing what they will find. In this case they struck geological gold, a mystery that some postdoc student could spend a lot of time analyzing.

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