Asteroids and the threat to Earth

 

NASA just shut down a planetary defence mission that tracks asteroids. Now what?

Artist’s impression of NEOWISE spacecraft. NASA/Caltech-JPL

Steven Tingay, Curtin University

Launched in 2011, NASA’s NEOWISE mission operated in Earth’s orbit until late last week. It detected more than 3,000 near-Earth objects or NEOs – asteroids or comets whose orbits can bring them close to Earth, even with the possibility of a collision. NEOWISE was shut down on August 8.

Surveying the population of NEOs is central to the emerging concept of planetary defence. That is, understanding and mitigating the risk of collision from asteroids large enough to do significant damage to Earth.

NEOWISE has made fundamental contributions to establishing the knowledge base for planetary defence, with more than 200 of the 3,000 objects it studied not known to us previously.

Now at mission end, and commanded by NASA to shut itself down, NEOWISE will re-enter Earth’s atmosphere before the end of this year. Where does that leave us with defending our planet?

All Known Asteroids in the Solar System (1999–2018)

From astrophysics to planetary defence

NEOWISE started life as a different mission, simply called WISE (Wide-field Infrared Survey Explorer). It was designed to study the infrared radiation from distant galaxies in the universe.

Infrared means “beyond red” – infrared light sits just past the red end of the spectrum of colours humans can see. We know infrared radiation better as the heat from the Sun, for example, or from a radiator keeping us warm in winter.

Infrared light is just outside the part of the spectrum that the human eye can see. brgfx/Shutterstock

When the coolant on the WISE mission ran out and these sensitive observations of galaxies couldn’t be carried out any more, NASA granted a mission extension under the NEOWISE name. They realised the telescope system was still sensitive enough to detect asteroids and comets that come close to Earth and the Sun, thereby having a very strong infrared signal.

NASA has an extraordinary history of squeezing extra life out of missions that reach completion. In this case, NEOWISE represented an entire second life, in an entirely different area of research.

How will we defend Earth now?

As well as the discovery and study of thousands of NEOs, NEOWISE established the foundation of knowledge that has informed a new, dedicated planetary defence mission. NASA’s NEO Surveyor will be launched in 2027.

NEO Surveyor’s goal is to discover approximately two thirds of all NEOs larger than 140 metres in diameter, over a five year baseline survey. This is a big step toward fulfilling the mandate United States Congress has provided to NASA: to discover 90% of all NEOs in this size range.

If they hit Earth, asteroids of this size could cause mass casualties if the impact were over a large metropolitan region.

You might think this poses a bit of a risk – shutting down NEOWISE three years before launching NEO Surveyor. What happens if one of these big asteroids comes our way in the next few years?

The risks are very small, as estimates show asteroids 140 metres in diameter impact Earth only approximately every 20,000 years. So, we would have to be extremely unlucky to have one in any given three-year period, especially impacting a place that would cause a large amount of damage. Only around 3% of Earth’s surface is occupied by urban areas.

NASA doesn’t really have much of a choice with the end of NEOWISE. The Sun’s 11-year activity cycle is picking up and causing Earth’s upper atmosphere, the ionosphere, to thicken. NEOWISE is flying through this ionosphere and can’t raise its orbit, so the ionosphere is inevitably dragging NEOWISE back to Earth.

NEO Surveyor started construction in 2023, so a 2027 launch is pretty impressively rapid, which is minimising the gap between NEOWISE and NEO Surveyor.

NEOWISE is scheduled to enter Earth’s atmosphere before the end of the year, but we don’t know precisely when.

Weighing almost 700kg, some of NEOWISE itself is likely to impact the surface of Earth. Hopefully it stays away from populated areas in the process – some recent re-entry events have resulted in space debris falling reasonably close to populated areas.

An asteroid is coming! What next?

Knowing about an asteroid on a collision course with Earth is one thing. Doing something about it is another thing altogether.

Huge steps toward planetary defence occurred two years ago, when the DART mission flew to an asteroid, impacted it, and changed its trajectory. This demonstrated it’s possible to change the course of asteroids, which could be used in the future to protect Earth from a collision.

Predicting potential Earth impacts as far as possible in advance, years preferably, gives the DART-style technology approach a chance.

The pioneering work of NEOWISE, and the upcoming comprehensive observations of NEO Surveyor, will place an enormous amount of information in our scientific bank, which will never go out of date and will be the basis for planetary defence for perhaps hundreds of years into the future.

Steven Tingay, John Curtin Distinguished Professor (Radio Astronomy), Curtin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Polling on American perceptions of internal conflict in the United States

                                                                                             Shutterstock

With the US presidential election this year, public opinion polling has been prolific particularly since the annoucnement of US president, Joe Biden that he would not be seeking a second term and nominating Vice President, Kamala Harris to be the Democratic Party candidate.

Other polls on general sentiment have been conducted and underscore the level of unease that is found in the United States at the moment.  The Marist Poll is one such survey that identified that around 50 per cent of people polled had a pessimistic outlook on the current situation of possible internal conflict n the US. The poll was conducted prior to the announcement of President Biden's withdrawal from the election on 21 July 2024.

How was the survey done ?

The survey of 1,192 adults was conducted April 16th through April 18th, 2024 by the Marist Poll. Adults 18 years of age and older residing in the United States were contacted through a multi-mode design: By phone using live interviewers or online. 

Results

More than 160 years after the Civil War began, nearly half of Americans think that it is either very likely or likely that they will see a second civil war. Perceptions about the possibility of another domestic conflict break along partisan, generational, racial and gender lines.

Link to the poll: Marist Poll: a nation divided

The value of Unions and the right to protest

Electrical Trades Union protest 2024 (c) Sentinel Owl

The formation and evolution of modern trade unions in the workplace dates back to the late 19th Century and the rapid changes in society brought by the Industrial Revolution. Prior to this, trade guilds of artisans have been shown to have existed as far back as the first century AD of the Roman Empire.  The advent of modern capitalism through the industrial revolution brought about significant changes in the basis of ''work' whereby the owners of capital engaged workers to provide labour for services and/or production of goods. The workers surrendered part of their rights of freedom and agency to take instructions from their employer (or master) in order to earn a wage. This process and unequal level of power for workers in turn led to the organisation of labour into unions to enable workers to protect themselves from complete exploitation. Over the past two centuries, these organisations have envolved and changed with the ebb and flow of economies, technological innovation and changing industrial relations laws.

Australia has long history of trade unions, derived in part from the influence of Mother England and the previous colonial period. Membership of trade unions has been declining as shown by research data from the Australian Bureau of Statistics. As at December 2022 -

• 12.5% of employees in the total workforce were trade union members
• Since 1992, the proportion of employees who were trade union members has fallen from 41% to 12.5%
• The Education and training industry (30%) and the Professionals occupation group (19%) had the highest rates of trade union membership.

Source link: Trade union membership  

Nonetheless these organisations remain a potent and relevant party in the industrial relations landscape.

This year, the Electrical Trades Union (ETU) representing the electricians and power industry workers has staged their campaign for higher wages via a Log of Claims to energy provider, Ausgrid and placed their protest outside the television studios of the Australian Broadcasting Corporation (ABC) in Ultimo, Sydney. It's a visually impactful and almost humourous presentation with large inflatables, even as the topic is a serious one (as shown in the images in this posting).

   

A Star is born

 Look up! A once-in-a-lifetime explosion is about to create a ‘new’ star in the sky

Stellarium Web Online Star Map

Tanya Hill, Museums Victoria Research Institute and Amanda Karakas, Monash University

Any night now, a “new star” or nova will appear in the night sky. While it won’t set the sky ablaze, it’s a special opportunity to see a rare event that’s usually difficult to predict in advance.

The star in question is T Coronae Borealis (T CrB, pronounced “T Cor Bor”). It lies in the constellation of the northern crown, prominent in the Northern Hemisphere but also visible in the northern sky from Australia and Aotearoa New Zealand over the next few months.

Most of the time T CrB, which is 3,000 light years away, is much too faint to be seen. But once every 80 years or so, it brightly erupts.

A brand new star suddenly seems to appear, although not for long. Just a few nights later it will have rapidly faded, disappearing back into the darkness.

A burst of life

During the prime of their lives, stars are powered by nuclear fusion reactions deep inside their cores. Most commonly, hydrogen is turned into helium creating enough energy to keep the star stable and shining for billions of years.

But T CrB is well past its prime and is now a stellar remnant known as a white dwarf. Its internal nuclear fire has been quenched, allowing gravity to dramatically compress the dead star.

T CrB also has a stellar companion – a red giant that has puffed up as it enters old age. The white dwarf mops up the swollen red giant’s gas, and this forms what’s known as an accretion disc around the dead star.

The matter keeps piling up on a star that’s already compressed to its limit, forcing a continual rise in pressure and temperature. Conditions become so extreme, they mimic what once would’ve been found inside the star’s core. Its surface ignites in a runaway thermonuclear reaction.

When this happens, the energy released makes T CrB shine 1,500 times brighter than usual. Here on Earth, it briefly appears in the night sky. With this dramatic reset, the star has then expelled the gas and the cycle can begin all over again.

Animation of a nova erupting as thermonuclear reactions ignite on the smaller white dwarf star. Credit: NASA/Conceptual Image Lab/Goddard Space Flight Center.

How do we know it’s due?

T CrB is the brightest of a rare class of recurrent novae that repeat within a hundred years – a time scale that allows astronomers to detect their recurrent nature.

Only ten recurrent novae are currently known, although more novae may be recurrent – just on much greater timescales that aren’t as easily tracked.

The earliest known date of T CrB erupting is from the year 1217, based on observations recorded in a medieval monastic chronicle. It’s remarkable that astronomers can now predict its eruptions so precisely as long as the nova follows its usual pattern.

The star’s two most recent eruptions – in 1866 and 1946 – showed the exact same features. About ten years prior to the eruption, T CrB’s brightness increased a little (known as a high state) followed by a short fading or dip about a year out from the explosion.

T CrB entered its high state in 2015 and the pre-eruption dip was spotted in March 2023, setting astronomers on alert. What causes these phenomena are just some of the current mysteries surrounding T CrB.

How can I see it?

Start stargazing now! It’s a good idea to get used to seeing Corona Borealis as it is now, so that you get the full impact of the “new” star.

Corona Borealis currently reaches its best observing position (known as a meridian transit) around 8:30pm to 9pm local time across Australia and Aotearoa. The farther north you are located, the higher the constellation will be in the sky.

The nova is expected to be a reasonable brightness (magnitude 2.5): about as bright as Imai (Delta Crucis), the fourth brightest star in the Southern Cross. So it will be easy to see even from a city location, if you know where to look.

We won’t have much time

We won’t have long once it goes off. The maximum brightness will only last a few hours; within a week T CrB will have faded and you’ll need binoculars to see it.

It almost certainly will be an amateur astronomer that alerts the professional community to the moment when T CrB outbursts.

These dedicated and knowledgeable people routinely monitor stars from their backyards on the chance of “what if” and therefore fill an important gap in night sky observations.

The American Association of Variable Star Observing (AAVSO) has a log of over 270,000 submitted observations on T CrB alone. Amateur astronomers are collaborating here and around the world to continually monitor T CrB for the first signs of eruption.

Hopefully the nova will erupt as expected sometime before October, because after that Corona Borealis leaves our evening sky in the Southern Hemisphere.

Tanya Hill, Senior Curator (Astronomy), Museums Victoria and Honorary Fellow at University of Melbourne, Museums Victoria Research Institute and Amanda Karakas, Associate Professor, School of Physics and Astronomy, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Coral reefs in jeopardy

Devastating coral bleaching will be more common, start earlier and last longer unless we cut emissions

Sarah_lewis/Shutterstock

Camille Mellin, University of Adelaide and Damien Fordham, University of Adelaide

Coral bleaching is becoming much more common as a result of increasingly severe and frequent marine heatwaves. Four global mass bleaching events have happened since 1998. Two of these were in the past decade.

Unless greenhouse gas emissions are cut to slow global warming, our new research shows that, by 2080, coral bleaching will start in spring, rather than late summer. Some events will last into autumn. The Great Barrier Reef’s maximum annual heat stress will double by 2050 if emissions do not slow.

Marine heatwaves stress corals, which then expel the symbiotic algae living in their tissue. These corals are left white and weakened. While not all bleached corals die immediately, prolonged heat stress harms their health and reproduction.

Our research used daily data on sea surface temperatures (instead of monthly data that models typically use) and supercomputing to produce high-resolution projections of marine heatwaves. We showed the risk of coral bleaching will be greatest along the equator. That’s also where the most biodiverse coral reefs are found.

Coral reefs cover only 1% of our oceans, but host at least 25% of all marine species. More than half a billion people worldwide depend on coral reefs for food.

So coral reefs are vital for the health of the ocean and people. They are also among the ecosystems most at risk from climate change.

Longer bleaching season will hit spawning

The US National Oceanic and Atmospheric Administration monitors marine heatwaves globally. Seasonal coral bleaching alerts are based on this data. Predicting coral bleaching risk over entire decades has proved much more challenging.

Recent improvements in climate modelling now allow marine heatwaves and coral bleaching risks to be predicted with high accuracy. Using daily projections of heat stress from many global climate models, we show the severity and duration of coral bleaching will soon reach uncharted territory.

By mid-century coral bleaching is expected to start in spring for most of Earth’s reefs, rather than late summer as is typical today. In equatorial regions, corals will be at high risk of bleaching all year round by the end of the century.

In many regions, corals spawn only once a year. These spectacular mass spawning events happen in a single week following a full moon in spring.

By 2040, this spawning event could coincide with severe bleaching risk. This would greatly reduce their reproductive success, causing large-scale coral loss.

Acropora coral spawning on Magnetic Island in Queensland, Australia. Coral Brunner/Shutterstock

Equatorial regions most at risk

We show the future risk of severe coral bleaching is uneven globally.

The greatest risk is along the equator. Equatorial regions are home to the most biodiverse coral reefs, including conservation hotspots such as the Coral Triangle. To make matters worse, marine life in these regions is particularly vulnerable to accelerated climate change.

Many equatorial species are already living at temperatures near their upper tolerance. They also generally have low abilities to move to track shifting climates. This leaves them at high risk of extinction.

Future risk of coral bleaching under a high-emission scenario (top) and benefit from climate mitigation (bottom). Adapted from Mellin et al. Science Advances 2024

Our research shows equatorial regions are set to benefit least from efforts to curb emissions. We expect significant emission cuts will reduce the annual duration of severe bleaching conditions in all areas except these regions.

The projected highest climate impacts coincide with highest social reliance on coral reefs. This will challenge human populations that rely heavily on their local reefs for their livelihoods and nutrition.

Improving coral reef management

Our research identifies Earth’s reef regions that are at lowest risk of increased bleaching. This will help conservation managers and policymakers prioritise efforts to limit loss of coral reef biodiversity.

We predict much less risk of coral bleaching in regions such as the northern coasts of Venezuela and Colombia, Socotra Island (opposite the Gulf of Aden) and Alor Kecil in Indonesia. Seasonal upwellings occur here, bringing cooler water to the surface that’s likely to limit the severity of heatwaves.

Identifying these future havens for coral reefs will help maximise the success of coral conservation strategies such as assisted evolution, coral restoration or transplantation.

These strategies can help maintain healthy coral populations at local scales, particularly if used on reefs where future climate impacts will be lower. By pinpointing these havens, our research will strengthen coral conservation.

Our research includes a user-friendly web-based tool for mapping future coral bleaching. It will help pinpoint locations for effective management interventions.

Curbing greenhouse gas emissions is the main solution to reduce future climate impacts on corals. However, other strategies are also vital to maximise coral reefs’ adaptation to climate change.

Camille Mellin, Senior Lecturer and ARC Future Fellow, School of Biological Sciences, University of Adelaide and Damien Fordham, Associate Professor of Global Change Ecology, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

World Environment Day 2024

World Environment Day is on 5 June 2024 and a link to the website: World Environment Day

The value of supportive care oncology for cancer

Exercise, therapy and diet can all improve life during cancer treatment and boost survival. Here’s how

PeopleImages.com - Yuri A/Shutterstock

Rob Newton, Edith Cowan University

With so many high-profile people diagnosed with cancer we are confronted with the stark reality the disease can strike any of us at any time. There are also reports certain cancers are increasing among younger people in their 30s and 40s.

On the positive side, medical treatments for cancer are advancing very rapidly. Survival rates are improving greatly and some cancers are now being managed more as long-term chronic diseases rather than illnesses that will rapidly claim a patient’s life.

The mainstays of cancer treatment remain surgery, chemotherapy, radiation therapy, immunotherapy, targeted therapy and hormone therapy. But there are other treatments and strategies – “adjunct” or supportive cancer care – that can have a powerful impact on a patient’s quality of life, survival and experience during cancer treatment.

Keep moving if you can

Physical exercise is now recognised as a medicine. It can be tailored to the patient and their health issues to stimulate the body and build an internal environment where cancer is less likely to flourish. It does this in a number of ways.

Exercise provides a strong stimulus to our immune system, increasing the number of cancer-fighting immune cells in our blood circulation and infusing these into the tumour tissue to identify and kill cancer cells.

Our skeletal muscles (those attached to bone for movement) release signalling molecules called myokines. The larger the muscle mass, the more myokines are released – even when a person is at rest. However, during and immediately after bouts of exercise, a further surge of myokines is secreted into the bloodstream. Myokines attach to immune cells, stimulating them to be better “hunter-killers”. Myokines also signal directly to cancer cells slowing their growth and causing cell death.

Exercise can also greatly reduce the side effects of cancer treatment such as fatigue, muscle and bone loss, and fat gain. And it reduces the risk of developing other chronic diseases such as heart disease and type 2 diabetes. Exercise can maintain or improve quality of life and mental health for patients with cancer.

Emerging research evidence indicates exercise might increase the effectiveness of mainstream treatments such as chemotherapy and radiation therapy. Exercise is certainly essential for preparing the patient for any surgery to increase cardio-respiratory fitness, reduce systemic inflammation, and increase muscle mass, strength and physical function, and then rehabilitating them after surgery.

These mechanisms explain why cancer patients who are physically active have much better survival outcomes with the relative risk of death from cancer reduced by as much as 40–50%.

Mental health helps

The second “tool” which has a major role in cancer management is psycho-oncology. It involves the psychological, social, behavioural and emotional aspects of cancer for not only the patient but also their carers and family. The aim is to maintain or improve quality of life and mental health aspects such as emotional distress, anxiety, depression, sexual health, coping strategies, personal identity and relationships.

Supporting quality of life and happiness is important on their own, but these barometers can also impact a patient’s physical health, response to exercise medicine, resilience to disease and to treatments.

If a patient is highly distressed or anxious, their body can enter a flight or fight response. This creates an internal environment that is actually supportive of cancer progression through hormonal and inflammatory mechanisms. So it’s essential their mental health is supported.

Chemotherapy can be stressful on the body and emotional reserves. Shutterstock

Putting the good things in: diet

A third therapy in the supportive cancer care toolbox is diet. A healthy diet can support the body to fight cancer and help it tolerate and recover from medical or surgical treatments.

Inflammation provides a more fertile environment for cancer cells. If a patient is overweight with excessive fat tissue then a diet to reduce fat which is also anti-inflammatory can be very helpful. This generally means avoiding processed foods and eating predominantly fresh food, locally sourced and mostly plant based.

Some cancer treatments cause muscle loss. Avoiding processed foods may help. Shutterstock

Muscle loss is a side effect of all cancer treatments. Resistance training exercise can help but people may need protein supplements or diet changes to make sure they get enough protein to build muscle. Older age and cancer treatments may reduce both the intake of protein and compromise absorption so supplementation may be indicated.

Depending on the cancer and treatment, some patients may require highly specialised diet therapy. Some cancers such as pancreatic, stomach, esophageal, and lung cancer can cause rapid and uncontrolled drops in body weight. This is called cachexia and needs careful management.

Other cancers and treatments such as hormone therapy can cause rapid weight gain. This also needs careful monitoring and guidance so that, when a patient is clear of cancer, they are not left with higher risks of other health problems such as cardiovascular disease and metabolic syndrome (a cluster of conditions that boost your risk of heart disease, stroke and type 2 diabetes).

Working as a team

These are three of the most powerful tools in the supportive care toolbox for people with cancer. None of them are “cures” for cancer, alone or together. But they can work in tandem with medical treatments to greatly improve outcomes for patients.

If you or someone you care about has cancer, national and state cancer councils and cancer-specific organisations can provide support.

For exercise medicine support it is best to consult with an accredited exercise physiologist, for diet therapy an accredited practising dietitian and mental health support with a registered psychologist. Some of these services are supported through Medicare on referral from a general practitioner.

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For free and confidential cancer support call the Cancer Council on 13 11 20.

Rob Newton, Professor of Exercise Medicine, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.