Category Archives: General News

Coherent rotational dynamics

Category : General News

The group of Prof. Jochen Küpper at DESY & Uni. Hamburg have reported in Nature Communications the observation of the laser-induced rotational dynamics of OCS, or, in simple words, a “movie” of OCS rotating in the ps-scale time. In this experiment a rotational wavepacket is created on a molecular beam of OCS using two laser pulses. The beam is later probed with a third laser.

A cut of 18 picoseconds of the molecular movie of the OCS rotation (Credit: Nat. Comm. 10, 3364 (1019), Open Access under a CCA license)

A word of caution: Remember that molecular rotation is different to the rotation of a macroscopic stick, as microscopic objects are described by quantum mechanics.


New SI

Category : General News , Science news

Last May 20, 2019 became effective the redefinition of the International System of Units (SI). In the new definition the kilogram (kg), kelvin (K) and mol are defined using numerical values of the Planck constant (h), the Boltzmann constant (kB) and the Avogadro constant (NA), respectively. A SI brochure is available from the Bureau International des Poids et Mesures. Farewell to the venerable kg prototype made of Pt/Ir.

In the picture above the new SI (graphic by Emilio Pisanti in wikipedia).


IYPT-UVa

Category : Books , General News , University

The Faculty of Sciences of the UVa has dedicated a Periodic Table wall poster featuring the spectra of the atomic elements, to celebrate the International Year of the Periodic Table (IYPT). This Periodic Table is a reproduction of the original work “Homage to the Elements” by visual artist Eugenia Balcells and contains a quote by Lucretius in “De rerum natura” (On the Nature of Things), written around 50BC, describing the atoms as “letters within words“.

The IYPT (and our barbaric times) are a good opportunity to read the 2012 Pulitzer winner “The Swerve” by Stephen Greenblatt, which contains a great presentation of the discovery of the book and the Epicurean Physics, which, even in a literary format, are far more reasonable than the opinions that arose in the 1500 years that followed its publication:

… atoms … are driven abroad and vexed
by blow on blow, even from all time of old,
they thus at last, after attempting all
the kinds of motion and conjoining, come
into those great arrangements out of which
this sum of things established is created
.



Black hole imaging

Category : Cosmology , General News

A radiotelescope array with instruments around the planet, including the Spanish participation in IRAM, produced an image of a black hole event horizon, as announced last April 10, 2019. The result comes after a decade long effort and new developments in millimeter-wave technology (230-450 GHz).

The position of the telescopes participating in the Event Horizon Telescope (EHT) and the Global mm-VLBI Array (GMVA).
The published image of the black hole at the center of Messier 87.

Ultima Thule

The end of 2018 and new year was full of space research news. In a very short time the Japanese Hayabusa2 touched an asteroid, the New Horizons spacecraft reached the Kuiper belt object Ultima Thule, and the Chinese probe Chang’e landed the Jade Rabbit 2 rover in the far side of the moon. The flyby of Ultima Thule is particularly interesting considering the distance of 6500 millions of km (equivalent to a radio attenuation of 303 dB at 7 GHz) and the fact that it was reached with about 35% of the remaining hydrazine fuel. New Horizons is expected to head towards another Kuiper object in the next years.

Two NASA images of Ultima-Thule taking in January 2019.
The Chinese lander on the far side of the moon.

COMs in Enceladus

An article in Nature reported the observation of astrophysically complex organic molecules (COMs) in cryo plumes ejected from the interior water ocean of Enceladus, one of Saturn satellites. The composition of the plumes was detected using mass spectrometry during a flyby of the spacecraft Cassini, before it was destroyed in 2017. Most of ice particles ejected from Enceladus are almost pure water, but a 1% is rich in organic molecules, some of them up to 200 amu. These results are the first evidence of complex organics from an extraterrestrial water ocean. The identity of these organic compounds is not clear, but they could contain carbon (C7 to C15), oxygen and eventually nitrogen. A prominent peak was associated to cationic forms of the benzene ring. Enceladus seems the only member of the solar system with a water ocean, an internal energy source and complex organics, apart from our planet.

Engineers Plan to Build Instrument to Study the Plumes of Enceladus

Picture Credits: NASA/JPL-Caltech/Southwest Research Institute


ExoMars

The European (ESA-Roscosmos) ExoMars Trace Gas Orbiter finished aerobraking dives and started taking data last April, 28. The Orbiter will specially check methane composition to discern if the  gas originated from geological or possible biological sources. The probe includes several ultraviolet and infrared spectrometers. The combination of mid-, near- and far-infrared spectra will provide identification of several atmospheric gases (H2O, O2, CO2, SO2, HF, HCl, etc).

In the picture below the Korolev crater, one of the first images from the orbiter.


Cosmic dawn

Category : Cosmology , General News

A VHF absorption signal at 78 MHz in the sky-averaged spectrum has been interpreted as a result of the formation of the first stars, a process that illuminated the universe with UV radiation and is called the cosmic dawn, as reported in a comment and article in Nature. The UV radiation would modify the excitation state of the 1420.4  MHz hydrogen spin atomic transition and would indicate the universe temperature. The linewidth suggest that the first stars appear 180 Myears after the Big Bang, while the flatten line profile has been connected speculatively with the interaction between normal matter and dark matter, which, if confirmed, would be truly remarkable.


Mars panorama

Following a five-year work of data collection the Mars rover “Curiosity” has produced an impressive panorama of the Gale impact crater that it has been exploring. The rover includes several spectroscopic experiments, including a LIBS (laser induced breakdown spectroscopy) instrument, capable to probe atomic composition at distances up to 7 m wit a 1064 nm IR laser. Other experiments include Raman spectroscopy (532 nm), Time-Resolved Fluorescence (TRF) spectroscopy and Visible and InfraRed (VISIR) reflectance spectroscopy (400 – 900 nm, 1.3 – 2.6 µm).

In the picture below the first LIBS spectrum on the “coronation” rock (August 2012).


Aromatics in space

Benzonitrile has been detected in the interstellar medium, as reported in Science. The interest of this aromatic molecule is the possibility of calculating the abundance of benzene from which it was generated, together with the growing interest to indentify the carriers of polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocycles. The report is introduced by Joblin and Cernicharo in the same issue. An updated list of molecules found in the space can be obtained from the Institut of Physics at the University of Cologne. In the picture below the Green Bank telescope. Related to this, Nature informs that the Arecibo telescope was saved from being dismantled thanks to a mistery funder.