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LATEST AUDIO > August 2019 | LATEST VIDEO > LOFAR
 

August 2019: Small Steps

August 2019

In the show this time, we talk to Jonathan Pober about his work with 21cm line and understanding galaxy formation and cosmology, George Bendo rounds up the latest news, and we find out what we can see in the August night sky from Ian Morison, Haritina Mogosanu and Samuel Leske.

The News

This month in the news: Protests over the thirty metre telescope in Hawaii and the 50th anniversary of the Apollo moon landing.

On the Big Island of Hawaii, opponents of the construction of the Thirty Meter Telescope (TMT) have physically blockaded the Mauna Kea access road, which allows people to travel to the observatories at the top of Mauna Kea. This is the latest in a series of protests that have taken place regarding the construction of the TMT as well as the operation and construction of other telescopes on the mountain.

To review, Mauna Kea is currently considered to be the best observing site in the Northern Hemisphere. Because the mountain is both broad and tall, the airflow over the top of the mountain is laminar rather than turbulent. This means that optical and near-infrared light from stars is blurred very little by the atmosphere, allowing astronomers to produce sharper images. Additionally, the summit is above an atmospheric inversion layer that forms nightly on the Big Island and that traps moisture at lower altitudes. As a result, the air at the top of the mountain is very dry, which is particularly ideal for submillimetre observations.

However, Mauna Kea has a unique ecosystem and multiple prehistorical and cultural sites, and opponents of the development of Mauna Kea are generally concerned about these sites. Aside from the summit itself, the most important high-altitude sites are Lake Waiau, which is an unusual high-altitude lake, and the adze quarries where prehistoric Hawaiians acquired unusually dense volcanic rocks for making stone tools. Moreover, many people currently go to the summit for modern-day Hawaiian spiritual practices. Opponents of Mauna Kea development are not only worried about the destruction of the pristine landscape but have also pointed to poor stewardship of the site by the University of Hawaii, which has been primarily responsible for the management of the site. The complaints include issues with the removal of trash and old equipment and reports of multiple chemical spills, although most such spills were indoors and did not harm the environment.

The TMT specifically has been targeted with multiple protests and lawsuits since Mauna Kea was selected as the site for the observatory in 2009. Construction was initially meant to start in 2015, but in a lawsuit filed by opponents, the construction permit was revoked because the process for issuing the permit was not followed correctly.

After re-applying for a building permit and clearing other lawsuits, approval was given to the TMT to start construction the week of the 15th of July. However, protesters blockaded the Mauna Kea access road on 13th of July before construction could start. Crowds of thousands of people appeared at the site. For safety reasons, the other observatories on the mountain decided to suspend all operations and order all employees and researchers to evacuate the mountain.

The protests have led to a number of events and controversies. Early during the protests, police arrested and then released 38 people at the site, many of whom were described by the protestors as kupuna, the Hawaiian term for spiritual leaders. A tropical storm at the beginning of August disrupted the protests, although a core group remained at the site. At a meeting of the Board of Regents for the University of Hawaii, opponents of Mauna Kea development called for the resignation of the president of the University of Hawaii, and the university's board of regents has approved the formation of an action group to investigate the current management of the mountain. Multiple celebrities have also visited the protesters to show their support, most notably actors Dwayne Johnson and Jason Momoa.

Having said all of this, the protests have largely been peaceful so far. However, no end to the protests is currently in sight.

In less controversial news, people in July celebrated the 50th anniversary of the first Apollo Moon Landing. The landing took place on the 20th of June 1969 and was the most notable events in the history of manned space exploration. This prompted many different events from across the world, including a reunion of people involved in the Apollo 11 mission at the Kennedy Space Center. Jodrell Bank Observatory scheduled the Bluedot music festival this year to coincide with the anniversary, and to mark the occasion, many of the events at Bluedot were Moon-themed. This anniversary has provided impetus to new projects to return to the Moon, particularly NASA's Artemis program, which has the goal of eventually building up a permanent presence on the Moon, and it will also provide support for China's and India's Moon exploration programs.

Interview with Jonathan Pober

Jonathan talks about his work with 21cm line and understanding galaxy formation and cosmology. He talks about the challenges and triumphs of characterizing the 21cm signals using the SKA phase telescopes.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during August 2019.

Ian Morison tells us what we can see in the northern hemisphere’s night sky during May 2019.

The Planets

Southern Hemisphere

Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speak about the Southern Hemisphere night sky during August 2019.

Odds and Ends

The Tibet Air Shower Gamma Experiment has announced the first ever detection of photons with an energy above 100 teraelectronvolt (TeV) coming from an astrophysical source. This Cherenkov telescope, which observes muons showering down on the earth as a result of extremely high-frequency light interacting with the atmosphere, has found 24 photons above 100 TeV coming from the Crab nebula. The Crab nebula is a supernova remnant about 2 kiloparsec away in the Taurus constellation. It is unclear how these photons are produced.

Late last year the KAGRA experiment in Japan was tested at cryogenic temperatures for the first time. An article by the team submitted this January and published this July details their work. The experiment is similar in concept to LIGO, it is an attempt to detect gravitational waves using the same principle of the difference between two laser beams sent out along arms kilometres in length. KAGRA has two major features to improve our knowledge in gravitational waves: it is underground to reduce the effects of seismic vibrations and the mirrors are cryogenically cooled to reduce the effects of thermal expansion and contraction on the mirrors used. The research concludes that the cryogenic system worked, cooling the mirrors to around 20K over the course of 35 days, and that alignment of the mirrors is achievable at these temperatures. The authors conclude by claiming the first scientific run of the experiment will be conducted in late 2019.

Recently, Wendy Freedman and her team from the University of Chicago found a new way to measure the expansion rate of the universe, also called the Hubble constant. Measurements of the Hubble constant have historically been contradictory to one another. The value recently derived from observations of Cepheid variables, for instance, is in a tension with that measured by studying the Cosmic Microwave Background. The new value, obtained by comparing the distance values of red giant starts to the apparent recessional velocity of target galaxies, sits inbetween those two measurements. The tension is not broken, and may require a new model of physics to resolve.

Show Credits

News:George Bendo
Interview:Jonathan Pober and James Stringer
Night sky:Ian Morison and Haritina Mogosanu
Presenters:Tiann Bezuidenhout, Ruoyu Zhu and Michael Wright
Editors:Naomi Asabre Frimpong, Tiann Bezuidenhout, Lizzy Lee, George Bendo and Deepika Venkattu
Segment Voice:Tess Jaffe
Website:Michael Wright and Stuart Lowe
Producer:Michael Wright
Cover art:This NASA photo shows Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (Eagle) during the Apollo 11 extravehicular activity. CREDIT: NASA

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