Tag: science

400b rogue planets

Japanese astronomers claim to have found free-floating “planets” which do not seem to orbit a star. They say they have found 10 Jupiter-sized objects which they could not connect to any solar system. They also believe such objects could be as common as stars are throughout the Milky Way. Using a technique called gravitational microlensing, they detected 10 Jupiter-mass planets wandering far from light-giving stars. Then they estimated the total number of such rogue planets, based on detection efficiency, microlensing-event probability and the relative rate of lensing caused by stars or planets. They concluded that there could be as many as 400b of these wandering planets, far outnumbering main-sequence stars such as our Sun

with this, my personal estimate for the drake equation goes to 8000.

Looking at the Kepler K2 data, the scientists documented 10s of short-duration microlensing events near the galactic core. Of these, 22 were previously detected during the OGLE and KMTnet ground-based campaigns, but 5 signatures hadn’t been seen before. Of these 5, 1 turned out to be a bound exoplanet, but the remaining 4 featured super-short microlensing events consistent with free-floating planets. 1 of the 4 candidate signatures was subsequently detected in ground-based data. The microlensing events, lasting for just several hours, suggest the discovery of unbound exoplanets no larger than Earth. It’s impossible to know what the conditions are like on these presumed rogue exoplanets, but they could be “cold, icy wastelands,” and, if similar in size to Earth, their surfaces would “closely resemble bodies in the outer Solar System, like Pluto.” The new paper suggests the presence of a large population of Earth-sized rogue planets in the Milky Way. It’s becoming clear that free-floating planets are common.

Interstellar Predation

It is often suggested that extraterrestial life sufficiently advanced to be capable of interstellar travel or communication must be rare, since otherwise we would have seen evidence of it by now. This in turn is sometimes taken as indirect evidence for the improbability of life evolving at all in our universe. A couple of other possibilities seem worth considering. One is that life capable of evidencing itself on interstellar scales has evolved in many places but that evolutionary selection, acting on a cosmic scale, tends to extinguish species which conspicuously advertise themselves and their habitats. The other is that — whatever the true situation — intelligent species might reasonably worry about the possible dangers of self-advertisement and hence incline towards discretion. These possibilities are discussed here, and some counter-arguments and complicating factors are also considered.

advertising our existence might be a suicidal mistake

Symmetry holds

The dynamics of a physical system is linked to its phase-space geometry by Noether’s theorem, which holds under standard hypotheses including continuity. Does an analogous theorem hold for discrete systems? As a testbed, we take the Ising spin model with both ferromagnetic and antiferromagnetic bonds. We show that—and why—energy not only acts as a generator of the dynamics for this family of systems, but is also conserved when the dynamics is time-invariant.

expanding the rules of symmetry beyond physics to cs, economics etc

Beyond the Heisenberg limit

Assuming that the particles interact with the object, but not with one another, the accuracy of such measurements grows in proportion to the number of particles in the beams, N. By allowing such particle interactions, scientists have now demonstrated a way to break this so-called Heisenberg limit. They used a beam of photons to measure the small magnetic field produced by a gas made up of 1m ultra-cold rubidium atoms. Normally, the spin of each photon would rotate by a certain amount, thanks to its interactions with the magnetic field of the atoms. But the frequency of the photons was chosen so that the photons also interacted with each other when they were in the gas, so that the presence of one photon altered the way a second behaved. These interactions led to a measurement accuracy that grew in proportion to N3/2 – greater than Heisenberg’s limit

i wish i understood this better, but how is that possible?

4th domain of life?

The researchers analyzed metagenomic data and used them to search the Global Ocean Sampling (GOS) Expedition dataset for novel lineages in 3 gene families commonly used in phylogenetic studies: trees that use small subunit ribosomal RNA, recA, and rpoB genes — highly conserved genes that appear in nearly all organisms, including the domains of prokaryotes, the bacteria, and archaea. They found some deep branches in the recA and rpoB phylogenetic trees that might represent viral genes. However, they acknowledge that the novel sequences possibly come from a new 4th major branch of cellular organisms on the tree of life.

not found in a petri dish or in nature but by trawling dna. there’s also

viruses make up the majority of the genetic information on the planet, more than the genetic information of all other species of life combined.

40% of the DNA in your gut is from an unknown domain of life. the notion of biological dark matter means there might be a 4th4th-domain-of-life domain of life.

Exosome drug delivery

the blood-brain barrier blocks delivery of many molecules that do wonderful things if injected directly into the brain, but injecting the brain isn’t quite as convenient as injecting a vein. Exosomes are lipid vesicles manufactured by cells for transporting diverse molecules to other cells, including signaling molecules such as micro RNAs. Now, they’ve been shown to carry their contents across the blood-brain barrier, and other work has shown that exosome-like particles can be made synthetically, with membranes chock-full of functional molecules for targeting cells and inducing responses from them. With diameters of 30 to 100 nm, exosomes have room for a lot of payload.

a boon for brain pharmaceuticals

97nm Optical Imaging

Not sure about being first, but metamaterials also go beyond the diffraction limit.

The smallest structures that conventional lenses are able to optically resolve are of the order of 200 nm. We introduce a new type of lens that exploits multiple scattering of light to generate a scanning nano-sized optical focus. With an experimental realization of this lens in gallium phosphide we have succeeded to image gold nanoparticles at 97 nm optical resolution. Our work is the first lens that provides a resolution in the nanometer regime at visible wavelengths.

2013-11-13: making microscopic images with visible light is limited by the diffraction limit, around 250nm. If you want to go smaller you have to use (often destructive) techniques like X-rays. This new technique can get to 30nm plus it makes beautiful pictures as a side effect.


2021-08-28: A 100x improvement in 10 years

Scientists have improved the spatial resolution from 8nm to 0.8nm of photoluminescence imaging. This has realized sub-molecular resolution with single molecule photofluorescence imaging for the first time.