Tag: astronomy

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.

Photopic Sky Survey

The Photopic Sky Survey is a 5000 megapixel photograph of the entire night sky stitched together from 37440 exposures. Large in size and scope, it portrays a world far beyond the one beneath our feet and reveals our familiar Milky Way with unfamiliar clarity. When we look upon this image, we are in fact peering back in time, as much of the light—having traveled such vast distances—predates civilization itself.

one guy spends a year photographing the milky way.

White Dwarf Habitable Zones

Planet hunters may be missing a trick. White dwarfs could be good targets for exoplanet searches. They are as common as Sun-like stars, the most common ones have a surface temperature of 5000 K and this should produce a habitable zone at distances of 0.01 AU for periods in excess of 3 ga. That’s long enough for something interesting to have emerged on these bodies.

my drake equation estimate just went up

Planet X?

at 15k AU. meanwhile the supposed nemesis would be at 50k-100k AU.
2018-10-02:

A new extremely distant object far beyond Pluto with an orbit that supports the presence of an even-farther-out, Planet X. “These distant objects are like breadcrumbs leading us to Planet X. The more of them we can find, the better we can understand the outer Solar System and the possible planet that we think is shaping their orbits—a discovery that would redefine our knowledge of the Solar System’s evolution”

Geomagnetic Galactic Record

During the solar journey through galactic space, variations in the physical properties of the surrounding interstellar medium (ISM) modify the heliosphere and modulate the flux of galactic cosmic rays (GCR) at the surface of the Earth, with consequences for the terrestrial record of cosmogenic radionuclides. 1 phenomenon that needs studying is the effect on cosmogenic isotope production of changing anomalous cosmic ray fluxes at Earth due to variable interstellar ionizations. The possible range of interstellar ram pressures and ionization levels in the low density solar environment generate dramatically different possible heliosphere configurations, with a wide range of particle fluxes of interstellar neutrals, their secondary products, and GCRs arriving at Earth. Simple models of the distribution and densities of ISM in the downwind direction give cloud transition timescales that can be directly compared with cosmogenic radionuclide geologic records. Both the interstellar data and cosmogenic radionuclide data are consistent with cloud transitions during the Holocene, with large and assumption-dependent uncertainties. The geomagnetic timeline derived from cosmic ray fluxes at Earth may require adjustment to account for the disappearance of anomalous cosmic rays when the Sun is immersed in ionized gas.

the magnetization of ancient rocks can be used to calculate the 3d shape of galactic dust clouds.

The Future Of Astronomy

Fundamental changes are taking place in the way we do astronomy. In 20 years time, it is likely that most astronomers will never go near a cutting-edge telescope, which will be much more efficiently operated in service mode. They will rarely analyse data, since all the leading-edge telescopes will have pipeline processors. And rather than competing to observe a particularly interesting object, astronomers will more commonly group together in large consortia to observe massive chunks of the sky in carefully designed surveys, generating petabytes of data daily.
We can imagine that astronomical productivity will be higher than at any previous time. PhD students will mine enormous survey databases using sophisticated tools, cross-correlating different wavelength data over vast areas, and producing front-line astronomy results within months of starting their PhD. The expertise that now goes into planning an observation will instead be devoted to planning a foray into the databases. In effect, people will plan observations to use the Virtual Observatory.