The most distant object in the solar system
Astronomers have found the most distant Kuiper Belt object yet, more than three times the distance from Pluto with a diameter of between 300 to 600 miles across.
Tag: astronomy
Phobos is being pulled apart
A new computer model suggests that the grooves on Phobos are caused by tidal forces that are slowly pulling the Martian moon apart.
Don’t panic, however. The data suggests that the moon won’t come apart for at least 30 million years.
Posted from Tucson.
Two Mauna Kea protesters convicted but get minor sentences
Two protesters who blocked a road leading to the summit of Mauna Kea to block construction vehicles for the Thirty Meter Telescope (TMT) have been convicted of misdeamenors and given very minor sentences.
The state requested six months’ probation, and that they stay off Mauna Kea Access Road for the period of probation. Prosecutors also requested 72 hours of community service in lieu of a $500 fine. Fujiyoshi [one of the protesters] asked for a jail sentence instead of community service, and was sentenced to five days. He will serve one day in jail, with credit for time served; six months’ probation; and was ordered to remain off the access road. Lindsey-Kaapuni [the other protester] argued against probation, and was sentenced to 100 hours of community service.
The state here has no easy solution. If it demands severe punishment the press will make the protesters martyrs. If it lets them off then the protesters will know they can protest as much as they want and face no consequences.
Right now I do not see TMT ever getting built on Mauna Kea. I also see the slow removal of the telescopes already there to be certain, given time. The protesters are in control, and they oppose this search for knowledge about the universe.
No sign of alien civilization at distant star
The uncertainty of science: Two weeks of targeted observations by the Allen Telescope Array in California have detected no clear signal of an alien civilization at the star KIC 8462852 where Kepler observations have seen variations that could possibly be caused by giant alien structures.
Two different types of radio signals were sought: (1) Narrow-band signals, of order 1 Hz in width, such as would be generated as a “hailing signal” for societies wishing to announce their presence. This is the type of signal most frequently looked for by radio SETI experiments. (2) Broad-band signals that might be due to beamed propulsion within this star system. If astroengineering projects are really underway in the vicinity of KIC 8462852, one might reasonably expect the presence of spacecraft to service this activity. If these craft are propelled by intense microwave beams, some of that energy might manifest itself as broad-band radio leakage. “This is the first time we’ve used the Allen Telescope Array to look for relatively wide-band signals, a type of emission that is generally not considered in SETI searches,” said SETI Institute scientist Gerry Harp.
Analysis of the Array data show no clear evidence for either type of signal between the frequencies of 1 and 10 GHz. This rules out omnidirectional transmitters of approximately 100 times today’s total terrestrial energy usage in the case of the narrow-band signals, and ten million times that usage for broad band emissions.
The data shows no sign of alien civilization, but it also does not eliminate the possibility. More detailed observations are required to do that.
Recreating the changing giant starspots on a distant star
Astronomers have recreated what they think is the evolution of the giant sunspots on a distant star, covering the period from 2006 to 2012.
More importantly, Künstler’s team measured the time it takes for starspots to decay and used that information to estimate properties of the star’s magnetic field. For example, the star’s activity cycle appears to last about 26 years, more than double the Sun’s 11-year cycle.
You can see a video of this recreation at the link.
Rosetta special science issue
For those who want to read some interesting science papers, on Friday the journal Astronomy & Astrophysics published a special issue devoted to the results from Rosetta and Philae.
The issue includes 46 papers, many of which are open access and thus available at no cost to the general public. Many were published previously and include their press releases. These earlier results have already been posted here at BtB, but now they the results are gathered together in one place.
Fiber optic cable damaged on Mauna Kea
On the same day hundreds of protesters were blocking construction vehicles from reaching the top of Mauna Kea, the fiber optic connection between the observatories on the summit malfunctioned. Workers have now discovered that the malfunction was caused by a damaged cable that police are now investigating.
The report does not provide any real details, so this failure could be quite innocent. That police are now investigating it and that it took place on the same day as the protests however suggests that it was sabotage.
Comet 67P/C-G has passed peak brightness
Using both ground-based and Rosetta observations scientists have now measured when the comet reached its peak brightness as well as how much material it lost during this orbit’s closest approach to the Sun.
Based on Rosetta’s pre-perihelion measurements that indicate the dust:gas ratio was approximately 4 , that means roughly 80% of the material being lost is dust, with the rest dominated by water, CO, and CO2 ices. (Note: at the time of that blog post an estimate of 3 was made for perihelion, but the actual data has yet to be analysed.) In any case, using 3 and 4 respectively, the total mass loss rate at its peak is likely in the range of about 100,000–115,000 tonnes per day.
Of course, that’s not a huge amount compared to the comet’s overall mass of around 10 billion tonnes. But nevertheless, a very simple calculation reveals that if, for example, the comet lost that much mass continuously for 100 days, it would correspond to roughly 0.4-0.5 metres of its surface being removed in that time.
In other words, the surface lost about 1.5 feet during close approach.
Peak brightness occurred near the end of August, and has been declining since.
The largest astronomical image ever
Astronomers have assembled the largest single image of the entire Milky Way ever taken.
It is 46 billion pixels across.
The amazing view of the Milky Way was built out of 268 individual views of the galaxy that includes the sun and the Earth, captured night after night over the course of five years with telescopes in Chile’s Atacama Desert. Astronomers at Ruhr-Universität Bochum used the data to examine stars whose brightness changes over time — and the image portrays more than 50,000 new objects with variable brightness that have never been recorded before.
Hawaii names third telescope to be removed from Mauna Kea
The dark ages return! The University of Hawaii has announced that the UKIRT Observatory on Mauna Kea will be decommissioned, making it the third telescope to be removed in order to try to satisfy the protesters hostile to the construction of the new Thirty Meter Telescope.
You wanna bet this won’t satisfy the protesters and that they will demand more while refusing to end their protests?
Kepler finds a star no one can explain
Observations using Kepler have uncovered a star whose light fluctuations can only be explained in two ways.
First,
If another star had passed through the unusual star’s system, it could have yanked a sea of comets inward. Provided there were enough of them, the comets could have made the dimming pattern. But that would be an extraordinary coincidence, if that happened so recently, only a few millennia before humans developed the tech to loft a telescope into space. That’s a narrow band of time, cosmically speaking.
Second? Maybe the star’s light is being blocked by a swarm of megastructures built by an alien civilization. They intend to look for radio emissions from the star in wavelengths associated with technology to see if this theory has any possibility.
New weather maps of Jupiter
Using the Hubble Space Telescope astronomers have compiled a new set of maps of Jupiter, showing changes in the gas giant’s bands and spots, including the Giant Red Spot.
The scientists behind the new images took pictures of Jupiter using Hubble’s Wide Field Camera 3 over a ten-hour period and have produced two maps of the entire planet from the observations. These maps make it possible to determine the speeds of Jupiter’s winds, to identify different phenomena in its atmosphere and to track changes in its most famous features.
The new images confirm that the huge storm, which has raged on Jupiter’s surface for at least three hundred years, continues to shrink, but that it may not go out without a fight. The storm, known as the Great Red Spot, is seen here swirling at the centre of the image of the planet. It has been decreasing in size at a noticeably faster rate from year to year for some time. But now, the rate of shrinkage seems to be slowing again, even though the spot is still about 240 kilometres smaller than it was in 2014.