Fast Radio Bursts are one of my favourite astronomical phenomena, because their cause or origin is still completely unknown. They are very short bursts of radio-frequency radiation, lasting just a few milliseconds, but of colossal intensity. There have been only about 37 catalogued to date, all one-offs except FRB 121102.
FRB121102 is a “repeater” – a series of bursts were observed coming from the same source in 2012, then again on several days in 2015, and 15 more bursts during 30 minutes in 2017. The origin appears to be a galaxy about 2 billion light years away.
Although spinning black holes and neutron stars are possible candidate for generating the FRBs, there is no regularity of pulse in the transmissions as there is with spinning pulsars. One outside, but not discounted, possibility is that the source of the FRBs is some sort of extraterrestrial intelligent action – an attempt at communication or the utilisation of power for some purpose.
The new news is that researchers have re-analysed the data from August 26, 2017, when 21 bursts were detected, and they have found another 72 pulses by using AI – a convolutional neural network.
A lone planet-size object (called SIMP J01365663+0933473) has been observed about 20 light years away. It is thought to be a “brown dwarf” – that is an object which is not quite large enough to attain the density needed to start hydrogen fusion and become a star. Scientists estimate the critical size between failed-star and ordinary star at about 13 times the mass of Jupiter. And the mass of this object is – yes – 12.7 times the mass of Jupiter – so it only just failed! It is said to be relatively young – about 200 million years old, and on its own – not orbiting a star.
But the most interesting property of the object is that it has an extremely strong magnetic field – more than 200 times as strong as Jupiter’s, which causes it to have strong auroras. The mechanism generating its magnetic field is unknown. Earth has auroras due to the interaction between the solar wind and Earth’s magnetic field. This object has no solar wind to interact with, so the mechanism may depend on an orbiting object. (Jupiter and its moon Io have a similar interaction.)
There are two basic approaches to measuring the rate of expansion of the universe:
a) using Cepheid variable stars – their brightness tells us how far away they are, and their redshift facilitates calculating the expansion rate
b) deductions from ripples in the CMB (Cosmic Microwave Background) – originating from the big-bang
These two methods have become more refined over time, but their measured values are some way apart – “about four times the size of their combined uncertainty.” This is according to research published in the Astrophysics Journal, July 12th.
The simplest explanation would be that the expansion rate is greater in the nearby universe than the more distant universe – but such a conclusion is incompatible with the current model, and would require new physics. Research is ongoing.
Update: 8th February 2019: A new technique has been described for measuring the rate of expansion of the Universe (the Hubble constant). Observing the duplicate images of quasars that show when an intervening galaxy acts as a gravitational lens, astronomers can use the slight differences in light path for the images, (which are revealed by the slight difference in arrival-time of brightness variations), to measure the distances to the lens-galaxy and quasar. Combining this with the red-shift gives a measurement of the Hubble Constant – in this case 72.5. This agrees with the Cepheid variable measurements ((a) above) but is 8% higher than measurements form the ancient universe i.e. the CMB measurements. This goes some way to confirming that the rate of expansion is increasing, but does not provide any explanation why.
Research published today in the journal “Neuron”, from analysis of DNA and RNA in Alzheimer brains, shows that Herpes virus HHV-6A and 7 (as well as the cold sore Herpes HSV-1) are present at higher levels in Alzheimer brains than normal brains, and that the level is associated with severity.
It is posited that the virus suppresses a microRNA which usually turns off a specific gene. Indeed when they bred mice deficient in that mRNA, they found the mice developed abundant amyloid plaques – the hallmark of Alzheimers.
Alternatively it may be that amyloid plaque is generated as a defence by the brain against the virus, but that the immune response cascades out of control.
A lot more research is needed to clarify, and unfortunately the Alzheimer research community is currently rather hostile to the idea that microbes are involved in the disease process. (Interestingly the researchers were not looking for viral implication, it just showed up in the data.)
I was impressed by this new technology reported on Futurism today.
The system bounces WiFi signals through a wall, analyses the radio-frequency heat map echoes which bounce back, and, using AI, reconstructs the presence of persons on the other side. Apparently it can also identify individuals by their movement and posture profiles.