Ancient Dead Galaxy Sets New Record

W. M. Keck Observatory press release

Galaxy ZF-COSMOS-20115
Artist’s impression of galaxy ZF-COSMOS-20115. The galaxy has likely blown off all the gas that caused its rapid star formation and mass growth, and rapidly turned into a compact red galaxy. Credit: CREDIT: Leonard Doublet/Swinburne University of Technology.
An international team of astronomers has, for the first time, spotted a massive, inactive galaxy from a time when the Universe was only 1.65 billion years old. This rare discovery, made using the world-class W. M. Keck Observatory on Maunakea, Hawaii, could change the way scientists think about the evolution of galaxies.

This research publishes today in the journal Nature, with Professor Karl Glazebrook, director of Swinburne’s Centre for Astrophysics and Supercomputing , as the lead author. To characterize the faint galaxy, the discovery team used MOSFIRE, the most in-demand instrument on the 10-meter Keck I telescope.

“This observation was only possible due to the extreme sensitivity of the new MOSFIRE spectrograph,” said Glazebrook. “It is the absolute best in the world for faint near-IR spectra by a wide margin. Our team is indebted to the accomplishment of Chuck Steidel, Ian McClean, and all the Keck Observatory staff for building and delivering this remarkable instrument.”

Astronomers expect most galaxies from this epoch to be low-mass minnows, busily forming stars. However, this galaxy is ‘a monster’ and inactive.

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Typical Hawaiʻi Shoreline

Picture postcard beaches of white sand with turquoise blue water are what so many tourists imagine when Hawaiʻi is mentioned. Add a few coconut palm trees and you have the ideal beach of song and legend.

Mauna Kea Beach
The ideal Hawaiian beach represented by Mauna Kea beach on the Kohala Coast.
What surprises many tourists is that this postcard ideal is not the reality of our island. Black rock shorelines are the norm. Once under water you will find the sandy areas are interspersed with coral reef, the rocky shorelines usually supporting extensive coral reef rather than sand.

It is the coral that is the source of the white sand beaches here in Hawaiʻi, ground coral chewed and digested by the many coral eating fish. The pretty triggerfish and parrotfish chew the coral constantly, crushing the coral into a fine grained sand. Our pretty sandy beaches are literally fish shit.

Old Airport beach
Typical shoreline along the Kona coast, if there is sand, it usually becomes rock and coral at the waterline
While not exactly rare, there are quite a few, beaches where the sand continues into the water are not the rule along the Kona coastline. Most of the coastline feature black lava shorelines where the water crashes against bare rock. This rocky shoreline accounts for something like 90% or more of the coastline of the Island of Hawaii.

This stands as a stark contrast to other tropical shorelines around the world, where miles upon miles of beach are not uncommon, sand as far as the eye can see. Here on the Big Island the few truly good beaches are treasured and well used parks.

Coconuts are not the usual shoreline tree either, that role belongs to either the kiawe tree or what is locally called ironwood. Both names are not what you would find in the botanical texts. Kiawe is the island name for what the rest of the world calls mesquite or Prosopis pallida, a drought tolerant tree that covers much of the dry leeward shorelines. Likewise the local ironwood is actually the beach she-oak or Casuarina equisetifolia. The rather confusing name ‘ironwood’ is used for over thirty different species around the world.

Another surprise to many is that this island has black sand beaches. In place of ground coral these beaches are ground up lava, often created by the interaction of hot lava and cold water shattering the rock into a deep black sand. There is even a green sand beach, where the sand is in large part made up of the semi-precious gemstone olivine.

Hawaiʻi is the youngest island in the chain, the forces of erosion, coral growth, and hungry fish, have not had enough time to create the long sandy beaches. These beaches become more common as you jump northward from island to island. Oahu or Kauai have extensive beaches along a much large percentage of shoreline. The islands in the northwest Hawaiʻian islands, places like Kure and Midway are pretty much nothing but sandy beach.

We do have beaches, and they are pretty good.

Jupiter at Opposition

Jupiter will pass through opposition at 10:58HST today.

Jove
Jupiter and the moons Europa, Ganymede and Callisto (left-right)
Jupiter orbits the Sun once every 11.86 years. As the giant planet continues on its way the Earth swings around much faster on our inside track. As a result we lap Jupiter once every 399 days, passing between the planet and the Sun. During opposition Jupiter will rise at sunset, transit at midnight, and set at dawn. This makes the planet available for observation for the entire night.

Look for a bright object rising in the eastern sky after sunset. It is difficult to mistake for anything else, shining at it’s brightest during opposition, a brilliant -2.7 magnitude. For the remainder of the spring and much of the summer, the planet will be quite prominent in the evening sky.

Observatory Still Life Gallery

Often you just need to take note of the small scenes that make up daily life. Over the years I have made an effort to photograph these scenes, there is so much richness in our everyday existence that too many do not notice…

Venus Appears in the Dawn

The bright planet Venus will appear in the dawn sky over the next couple weeks, climbing higher to become the morning star for the remainder of 2017. It is currently 15° from the Sun and shining at magnitude -4.3, bright enough to be seen against the dawn sky. It will reach maximum elongation on June 3rd, 46° ahead of the rising Sun.

Venus Events for 2017

  Date UT Separation Mag
Maximum Elongation Jan 12 47.1°E -4.4
Inferior Conjunction Mar 25    
Maximum Elongation Jun 3 45.9°W -4.3
 
Source: NASA Sky Calendar

Bang-Bang

I took a break from working with a “big” microcontroller to work with a little one. The PIC12C671 is definitely little when compared with the PIC18F66K80 I am using in the GenPIC utility PCB. With less than 2k of program space and a mere 128 bytes of RAM it is definitely limited. Consider that the chip only has eight pins, two of which are power and ground, leaving six I/O pins to get the job done. No problem, I only need two I/O pins for this task and that few bytes of RAM is more than enough!

A simple heater using a bang-bang controller.
A simple heater using a bang-bang controller.
This project is pretty basic… A bang-bang heater controller. This simple form of controller simply turns on and off as the temperature (or some other controlled parameter) goes up and down, there is no attempt to vary the output, all or nothing. Bang on, bang off, or simply a bang-bang controller as it is known in the trade.

A bang-bang controller is inherently reliable and stable because it uses two different control setpoints, a high and a low. Because these control points are separated by a large margin, called hysteresis, the controller will not oscillate or rapidly turn on and off. In this case the heater will not turn on until the temperature falls below 10°C and will not turn back off until the temperature rises above 15°C. That five degree margin is called hysteresis, and ensures a good period of time between on and off.

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Mercury at Maximum Elongation

Today Mercury will be at maximum eastern elongation, as high in the evening sky as it will appear for this current apparition. After today the planet will slide back into the sunset, passing through inferior conjunction on April 19th to reappear in the morning sky around the end of the month.

Mercury Transit 9May2016
Mercury transiting the Sun on May 9, 2016. Celestron C8 and Canon 6D at f/10.
Mercury typically completes three morning and three evening apparitions in each year. While the innermost planet never gets very far from the Sun, maximum elongation represents the best time to observe Mercury as high in the sky as possible.

There are no transits of Mercury in 2017, the next will be Nov 11, 2019.

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