Tag: science

Hubble image shows several dozen boulders flung from Dimorphos

9:40 am

Boulders drifting from Dimorphos
Click for original image.

Using the Hubble Space Telescope, astronomers have photographed several dozen boulders that were flung off of the asteroid Dimorphos following the impact by the space probe DART. The picture to the right, reduced and brightened to more clearly show those boulders, was taken on December 19, 2022, four months after DART’s impact.

These are among the faintest objects Hubble has ever photographed inside the Solar System. The ejected boulders range in size from 1 meter to 6.7 meters across, based on Hubble photometry. They are drifting away from the asteroid at around a kilometre per hour.

The blue streak is the dust tail that has streamed off of Dimorphos since the impact, pushed away from the sun by the solar wind.

2 comments

The possibility of more than one exoplanet sharing the same orbit

9:27 am

PDS 70, as seen by ALMA
The Trojan debris clouds around PDS 70, as seen by ALMA

The uncertainty of science: Astronomers have detected evidence that suggests the possibility of more than one exoplanet sharing the same orbit around PDS 70, a star 400 light years away.

This young star is known to host two giant, Jupiter-like planets, PDS 70b and PDS 70c. By analysing archival ALMA observations of this system, the team spotted a cloud of debris at the location in PDS 70b’s orbit where Trojans are expected to exist.

Trojans occupy the so-called Lagrangian zones, two extended regions in a planet’s orbit where the combined gravitational pull of the star and the planet can trap material. Studying these two regions of PDS 70b’s orbit, astronomers detected a faint signal from one of them, indicating that a cloud of debris with a mass up to roughly two times that of our Moon might reside there.

The press release — as well as most news reports — touts the possibility that they have found a second planet in this orbit. They have not, and are likely not going to. As noted above, the data indicates the presence of “a cloud of debris”, which is most likely a clustering of Trojan asteroids, just as the more than 12,000 asteroids we see in the two Trojan points in Jupiter’s orbit.

Nonetheless, this is the first detection of what appears to be a Trojan clustering in the accretion disk of a young star.

2 comments

Scientists discover in archival data a slowly pulsing object that has been beating since 1988

8:48 am

The uncertainty of science: Using archival data, scientists have discovered a previously undetected but very strange slowly pulsing object that has been doing so since 1988.

Astronomers have found an ultra-slow, long-lasting source of radio-wave pulses, and they are perplexed as to its true nature. While “regular” radio pulsars have very short periods, from seconds down to just a few milliseconds, this source emits a brief pulse of radio waves about three times per hour. What’s more, it has been doing this for decades. “I do not think we can say yet what this object is,” says Victoria Kaspi (McGill University), a pulsar researcher who was not involved in the new study.

Natasha Hurley-Walker (Curtin University, Australia) and her colleagues discovered the mysterious source in data from the Murchison Widefield Array (MWA) observatory in Western Australia. They carried out follow-up observations with the MWA and with other radio observatories in Australia and South Africa. Known as GPM J1839-10, the tardy blinker is located at a distance of some 18,500 light-years away in the constellation Scutum. Archival data from the Very Large Array in New Mexico and the Indian Giant Metrewave Radio Telescope reveal that it has been pulsating at least since 1988, with a period of just under 22 minutes (1,318.1957 seconds, to be precise).

In a sense, the object is a pulsar, since on a very basic level it does what all pulsars do, send a radio beat in our direction in a precise pattern. The problem is that according to present theories that say pulsars are actually magnetized neutron stars rotating quickly, this object is rotating too slowly to be one.

5 comments

Ancient lava vent high on a Martian volcano

2:39 pm

Ancient lava vent high on a Martian volcano
Click for original image.

Today’s cool image illustrates the once violent and active volcanic past of Mars, now long dormant. The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 11, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as a “vent and channel” located high on the northeast flanks of the giant volcano Arsia Mons.

The rim around the vent suggests that lava had once bubbled up out of the vent and hardened around it, as most of the lava flowed downhill along the channel. And though this vent appears to be the source of this channel, it is not. The channel continues to the southwest uphill until it reaches the edge of Arsia Mons’ caldera, a region where there are many such vents, many much larger and deeper than this one.
» Read more

0 comments

Stanford president resigns due to research fraud allegations

12:07 pm

The president of Stanford University, Marc Tessier-Lavigne, has now resigned because of allegations of fraud and data manipulation in papers published by him and others.

The report finds that overall Tessier-Lavigne “did not have actual knowledge of any manipulation of research data” and “was not reckless in failing to identify” the problems in the papers. Yet it concludes that he did not respond adequately when concerns were raised about the papers on PubPeer or by a colleague at four different points over 2 decades—most recently in March 2021. For example, it chides him for failing to follow up when Science did not publish the corrections he submitted.

The report also faults Tessier-Lavigne for his “suboptimal” decision not to correct or retract the 2009 Nature paper, despite “vigorous discussions” about what to do; instead, he and colleagues published follow-up papers revising the findings. Without “an appropriate appetite” for corrections, “the often-claimed self-correcting nature of the scientific process will not occur,” the report says.

In other words, he too often looked the other way when associates were sloppy or were found to have faked data.

This story is an addendum to one I posted yesterday, where a researcher in 2020 had found 1 in 4 clinical trials to be either unreliable or fraudulent. His revelation however was ignored by the medical community, just as Tessier-Lavigne ignored fraud or sloppiness at his own lab.

Nor has anything really changed in the medical research community. Though Tessier-Lavigne has stepped down, the actual perpetrators of the fraud are facing no punishment.

Despite the findings of data manipulation, the report does not assign responsibility to any specific members of Tessier-Lavigne’s lab or determine whether the data manipulation fit the federal definition of research misconduct, “fabrication, falsification, fabrication, or plagiarism.” Whether the findings should be reported to the federal Office of Research Integrity will be up to Stanford, Filip says.

It appears we can trust little from the modern medical research community. There is certainly good work being done, but telling the difference between the good and the bad is now very difficult, if not impossible.

6 comments

Astronomers detect white dwarf star with two faces

9:13 am

The uncertainty of science: Astronomers using ground-based telescopes have discovered a white dwarf star in which the surface chemistry of its two hemispheres are very different, one strongly dominated by hydrogen while the other instead dominated by helium.

The team used the Low Resolution Imaging Spectrometer (LRIS) on the Keck I Telescope to view Janus in optical wavelengths (light that our eyes can see) as well as the Near-Infrared Echellette Spectrograph (NIRES) on the Keck II Telescope to observe the white dwarf in infrared wavelengths. The data revealed the white dwarf’s chemical fingerprints, which showed the presence of hydrogen when one side of the object was in view (with no signs of helium), and only helium when the other side swung into view.

The article lists a lot of proposed explanations, most of which suggest the star’s magnetic field is acting to segregate the materials. All assume these observations are certain and that there is no mixing at all, something we should doubt considering the resolution of the data (a mere point that is rotating).

5 comments

Glacial evidence in the dry equatorial regions of Mars?

11:15 am

Is this evidence of glacial ice in the Martian dry equatorial regions?
Click for original image.

Cool image time! The picture to the right, rotated, cropped, rotated, and sharpened to post here, was taken on June 3, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the eastern half of a six-mile-wide unnamed crater with a depth of about 1,500 to 2,000 feet from rim to floor.

What makes this picture significant is the patchy material in the center of that crater floor, some of which looks almost like very old peeling paint. It also resembles the kind of glacial features routinely seen in many craters poleward of 30 degrees latitude on Mars.

Is this another example of such glacial features? If so, its location is what makes it significant.
» Read more

0 comments

The results of one in four medical clinical trials are probably fraudulent or unreliable

9:11 am

In 2020 a researcher in Great Britain decided to analyze the raw data used by 500 medical clinical trials, and found that one in four contained fraudulent or unreliable data.

Carlisle, an anaesthetist who works for England’s National Health Service, is renowned for his ability to spot dodgy data in medical trials. He is also an editor at the journal Anaesthesia, and in 2017, he decided to scour all the manuscripts he handled that reported a randomized controlled trial (RCT) — the gold standard of medical research. Over three years, he scrutinized more than 500 studies.

For more than 150 trials, Carlisle got access to anonymized individual participant data (IPD). By studying the IPD spreadsheets, he judged that 44% of these trials contained at least some flawed data: impossible statistics, incorrect calculations or duplicated numbers or figures, for instance. And 26% of the papers had problems that were so widespread that the trial was impossible to trust, he judged — either because the authors were incompetent, or because they had faked the data.

Carlisle called these ‘zombie’ trials because they had the semblance of real research, but closer scrutiny showed they were actually hollow shells, masquerading as reliable information. Even he was surprised by their prevalence. “I anticipated maybe one in ten,” he says.

There is the real story, however.

Carlisle rejected every zombie trial, but by now, almost three years later, most have been published in other journals — sometimes with different data to those submitted with the manuscript he had seen. He is writing to journal editors to alert them, but expects that little will be done.

In other words, the peer-review medical community continues to allow fake research to be published, even when it has been warned that research is fake.

But of course, we must trust everything they tell us. They are SCIENTISTS, and we must “follow the SCIENCE!”

2 comments

Flat-topped Martian mesa

3:58 pm

Flat-topped mesa on Mars
Click for original image.

Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on April 18, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows only one of many flat-topped mesas in a chaos terrain region dubbed Oxia Chaos.

The mesa top is about 540 feet above the floor of the canyon to the north, which in turn is about 840 feet below the flat terrain north of it. That flat terrain to the north is not part of the chaos terrain, however, but the northern rim of the plateau that surrounds the chaos. Moreover, this particular piece of rim is separating from the plateau, as shown near the top of this January 16, 2008 context camera image from MRO. At some point in the future it will break off and fall into that canyon and on top of this mesa.
» Read more

0 comments

Chandrayaan-3 completes second orbital maneuver

9:32 am

Chandrayaan-3's mission profile

According to India’s space agency ISRO, its lunar lander/rover Chandrayaan-3 today completed second orbital maneuver, raising the spacecraft’s orbit around the Earth from 41,762 by 173 kilometers to 41,603 x 226 kilometers.

The graphic to the right shows the entire mission profile of Chandayaan-3. It still has three more orbital adjustments to make in Earth orbit before it does its trans-lunar-injection burn to send it to the Moon. Once it arrives in lunar orbit it will then have to make six orbital adjustments to lower its orbit before making the descent to the surface.

The lunar landing itself is presently scheduled for August 23, 2023.

0 comments

Another look at the vastness of Valles Marineris on Mars

1:06 pm

The vast Valles Marineris
Click for interactive map.

This week I have returned several times to the giant Valles Marineris canyon on Mars in an attempt to capture its incomprehensible and glorious scale. Without question this canyon is going to become one of the prime tourist spots when humans begin living and working throughout the solar system. Fortunately, its vast size will mean that it will take many many centuries before it even becomes close to crowded there.

Today I try a different approach, using the global mosaic created by scientists at Caltech from the context camera images taken by Mar Reconnaissance Orbiter (MRO). That mosaic processes the images to allow one to see the surface from an oblique angle. The picture to the right covers one small part of the eastern end of Valles Marineris (the white rectangle in the inset), but though small the scale once again is gigantic.

The three white dots are our reference points, one on the north rim, one on the south, and one in the middle on the peak of that central mountain chain. Beginning from the south, the distance from the rim to the middle mountain peak is 43 miles, with the elevation dropping almost 13,000 feet to the floor of the south canyon, than rising almost 10,000 feet to the middle peak. The northern canyon is smaller. From the peak to the north rim is 27 miles, dropping about 9,300 feet and then rising about 8,500 feet to the north rim.

From rim to rim the distance is about 70 miles. Since the middle mountain chain about 18 miles wide, it fills only about 25% of the entire canyon.

In every case, the Grand Canyon would be merely be a small side canyon here. The depths are twice as deep, and the distances are many times larger. In width alone at this point Valles Marineris is seven times wider than the widest part of the Grand Canyon, and this is by far not Valles Marineris’s widest point.
» Read more

0 comments

India successfully launches Chandrayaan-3

8:35 am


Click for interactive map.

India today successfully launched its Chandrayaan-3 lunar lander/rover probe toward the Moon, carried aloft by its LV-M3 rocket (a variation of its GSLV) from its coastal spaceport in Sriharikota.

Chandrayaan-3 carries the Vikram lander, which will bring the Pragyan rover to the surface. Pragyan will spend about two weeks operating on the lunar surface. The location is indicated by the red dot on the map to the right, in the high southern latitudes. The white cross marks the lunar south pole. Russia’s Luna-25 is scheduled to launch sometime in mid-August.

It will take time to get Chandrayaan-3 into the right lunar orbit for landing, which is presently scheduled for August 13, 2023.

For India this was its fifth successful launch for the year, the most since 2019, before it panicked over COVID. The leaders in the 2023 launch race:

46 SpaceX
26 China
9 Russia
5 Rocket Lab
5 India

American private enterprise still leads China in successful launches 52 to 26, and the entire world combined 52 to 45, while SpaceX by itself still leads the rest of the world (excluding other American companies) 46 to 45.

1 comment
1 … 119 120 121 122 123 … 729