Tag: Georgia State University

Far, far away (in stellar terms).

Deep space is beyond anything we have ever known.

Like many other people, I am fascinated by the dark, clear, night sky. It appears to go on forever.

But this ‘foreverness’ is just our galaxy.

As is said in the following article: “…. if Earth were the size of a pea, the distance to Proxima Centauri would roughly equal the distance between New York and Sydney, Australia.”

The article shows how distant we are, how small we are, how irrelevant we are, in the vastness of the universe.

This article is republished courtesy of The Conversation.

ooOOoo

Could aliens ever visit Earth? An aerospace scientist unpacks the challenges of interstellar spaceflight

The universe is vast and teeming with stars – but if intelligent life exists, it may not be able to visit Earth. NASA, ESA, CSA, STScI, Rohan Naidu (MIT); Image Processing: Joseph DePasquale (STScI), CC BY

Kai James, Georgia Institute of Technology

On May 22, 2026, the Pentagon released a second batch of previously classified photos and videos showing what appear to be unexplained flying objects. These file dumps were the culmination of a process that was set in motion back in July 2023, when a group of government whistleblowers testified before Congress that the U.S. government was secretly in possession of extraterrestrial spacecraft and suspected alien body parts.

That congressional hearing marked the beginning of a cultural shift in which UFO reports are increasingly treated as a matter for serious discussion, both within the government and the scientific community.

A grainy photo of a dark, blurry object in the sky.
The Pentagon released over 200 previously classified UFO files in May 2026. Department of Defense

But is this newfound legitimacy deserved? As an aerospace scientist who studies aircraft and spacecraft design, I approach this question using math, physics and the principles of engineering. To assess the plausibility of alien visitors, it’s necessary to understand the obstacles that an extraterrestrial vessel would need to overcome to reach Earth.

The tyranny of distance

There is no evidence of intelligent alien life in our solar system. So any extraterrestrial visitors would likely have to come from another star system within our Milky Way galaxy.

Proxima Centauri, the star closest to our Sun, is located 4.25 light-years (about 25 trillion miles or 40 trillion kilometers) away.

For perspective, if Earth were the size of a pea, the distance to Proxima Centauri would roughly equal the distance between New York and Sydney, Australia.

Even the stars closest to Earth are incredibly far away.

Since only a fraction of stars are thought to host intelligent life, the nearest alien civilization – if one exists – is surely much farther away than Proxima.

A need for speed

Given the scale of interstellar distances, it’s inevitable that any alien voyage to Earth would span many years and possibly several centuries. But as the time spent in transit increases, so does the risk of catastrophic accidents or system malfunctions that could jeopardize the mission. So it’s important to avoid an overly lengthy journey by traveling as fast as possible.

No object can reach or exceed the speed of light (roughly 186,000 miles or 300,000 kilometers per second). But well before approaching that threshold, engineering constraints begin to assert themselves. Limited fuel availability and the potential for structural damage will restrict the spacecraft’s peak velocity.

There is no universally accepted upper limit on interstellar flight speeds, but studies tend to converge around 19,000 miles per second (30,000 km/s) – 10% of the speed of light – as a realistic cruise velocity. At this speed, a journey of 10 light-years will take approximately 100 years to complete.

Fueling the dream

Finding a way to accelerate the ship to its target cruise speed is the central challenge facing any would-be alien explorers.

Interstellar space is unforgivingly vast, but the emptiness has some advantages. The lack of atmosphere means there is no aerodynamic drag. So when the ship reaches its cruise speed, it can shut down its propulsion system and coast toward the final destination. Unfortunately, the lack of atmosphere also means there is nothing to slow the ship down prior to arrival. So ideally, the propulsion system would be used for both acceleration at the start of the trip and deceleration at the end.

One of the more exotic propulsion strategies employs high-powered laser beams to push the ship through space. The beam is projected from a stationary array near the travelers’ home planet and directed toward a thin reflective sail attached to the ship. The beam’s photons exert radiation pressure on the sail, propelling the ship forward.

This approach has a major advantage in that it requires no onboard fuel. But the amount of energy and infrastructure needed to operate the laser would be staggering. Also, beamed propulsion provides no mechanism for deceleration. At best, this method could be deployed as part of a hybrid strategy that uses a separate system for deceleration.

A more practical approach is to use rocket propulsion. Rockets generate propulsive force, also known as thrust, by expelling high-velocity exhaust in a rearward stream. By reversing the direction of the exhaust, rockets can also be used to slow the ship down.

Their main disadvantage is that rockets must carry their own fuel in addition to carrying the passengers, the habitat and other life-sustaining systems. The extra load necessitates even more fuel. In other words, you need fuel to transport your fuel. The result is a costly snowball effect that can cause the total fuel requirement to balloon to absurd proportions.

Rocket propulsion can be divided into three broad categories.

Chemical propulsion uses chemical reactions – typically combustion – to extract energy from the bonds between atoms. All human space missions thus far have used chemical propulsion. The problem with this method is that it accesses only a tiny fraction of the energy contained within the fuel.

Consequently, using chemical propulsion on a spacecraft with a cruise velocity of 19,000 miles per second (30,000 km/s) would require more fuel than all the mass in the observable universe.

Antimatter propulsion is theoretically the most efficient option. When antimatter comes into contact with ordinary matter, the two undergo mutual annihilation and 100% of their combined mass is converted into energy. This makes it possible to achieve the same cruise velocity – one-tenth the speed of light – with fuel accounting for less than a quarter of the ship’s total mass. This is science fiction-level fuel efficiency, which makes antimatter an attractive option for interstellar propulsion.

The downside is that antimatter is extremely unstable and difficult to make. To date, particle physicists have produced less than 20 billionths of a gram of antimatter. Moreover, these particles had lifespans lasting only fractions of a second and a price tag in the hundreds of millions of dollars.

Nuclear fusion offers a more viable alternative to antimatter. This approach harvests energy stored inside the nucleus of an atom using the same process that powers the Sun. With current technology, fusion engines remain aspirational, but they could, in theory, produce 10 million times more energy per kilogram than chemical rockets.

An illustration of a cylindrical spacecraft orbiting Earth
NASA has been working to develop nuclear propulsion. This artist’s impression shows what a nuclear-powered rocket could look like. John Frassanito & Associates/Wikipedia

Still, a fusion-powered ship with a cruise velocity of 19,000 miles per second (30,000 km/s) would require fuel equivalent to 150 times the mass of the ship itself.

A delicate balancing act

These numbers assume that our extraterrestrial visitors have figured out how to efficiently convert the energy released by their reactor – whether nuclear fusion or antimatter – into thrust.

Just as importantly, they must be able to create optimized fuel tank structures that are ultra lightweight yet highly secure. Designing the structure of the ship, from the fuel tanks to the hull, would be one of the biggest engineering challenges of the entire mission.

Interstellar space contains a sparse smattering of hydrogen atoms and microscopic grains of cosmic dust. At 19,000 miles per second (30,000 km/s), dust particles would smash into the ship’s hull with the energy of a .22-caliber bullet. The bombardment of hydrogen atoms would produce a violent cascade of radiation that could erode even the most resilient engineering materials.

Surviving the onslaught would require no less than a flying fortress with complex magnetic shielding. This would increase the total mass of the ship, which further drives up the demand for fuel.

This example is just one of the hundreds of delicate design trade-offs that would plague any interstellar vessel. Each individual design requirement acts as a filter, reducing the number of feasible solutions.

Finding a single system that simultaneously satisfies all the requirements is analogous to shopping for a car online. With each new filter you apply – four-wheel drive, black exterior, less than 10,000 miles on the odometer – the number of available options dwindles.

When design requirements are in tension with one another – for example, requiring a structure that is lightweight but also supremely durable – the number of feasible solutions can drop to zero.

No single law of physics prohibits an interstellar voyage to Earth. But the combined effects of hundreds of extreme, often conflicting engineering requirements may render it physically infeasible.

It’s also possible that alien civilizations have discovered novel technologies that outperform anything currently known to humans. But like the examples discussed here, any such technology will inevitably encounter its own engineering hurdles.

The trillion-dollar question

Ultimately, engineering challenges are just some of the many barriers to interstellar travel. Any prospective alien visitors must also have sufficient cognitive ability, technological maturity, physical resources, collective desire and proximity to Earth.

That said, if the stars were to align and an alien vessel made it to Earth intact, it would trigger a torrent of burning questions: Where are they from? What do they want? What are they made of?

But the question that would go furthest in shedding light on the deeper mysteries of the universe is, “How on Earth did they get here?”

Kai James, Professor of Aerospace Engineering, Georgia Institute of Technology

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

ooOOoo



Kai James poses the unanswerable questions in the last two paragraphs. And how about this statement: “Consequently, using chemical propulsion on a spacecraft with a cruise velocity of 19,000 miles per second (30,000 km/s) would require more fuel that all the mass in the observable universe.“

Plastics in the ocean

A fascinating insight into recovered plastic.

Like so many others we do our little bit regarding plastic but do not properly think about the issue. I have to admit that I am not even sure if all plastics are harmful or just some.

But I comprehend art!

That is why I am republishing, with permission, this article from The Conversation.

ooOOoo

My art uses plastic recovered from beaches around the world to understand how our consumer society is transforming the ocean

Pam Longobardi amid a giant heap of fishing gear that she and volunteers from the Hawaii Wildlife Fund collected in 2008. David Rothstein, CC BY-ND

Pam Longobardi, Georgia State University

I am obsessed with plastic objects. I harvest them from the ocean for the stories they hold and to mitigate their ability to harm. Each object has the potential to be a message from the sea – a poem, a cipher, a metaphor, a warning.

My work collecting and photographing ocean plastic and turning it into art began with an epiphany in 2005, on a far-flung beach at the southern tip of the Big Island of Hawaii. At the edge of a black lava beach pounded by surf, I encountered multitudes upon multitudes of plastic objects that the angry ocean was vomiting onto the rocky shore.

I could see that somehow, impossibly, humans had permeated the ocean with plastic waste. Its alien presence was so enormous that it had reached this most isolated point of land in the immense Pacific Ocean. I felt I was witness to an unspeakable crime against nature, and needed to document it and bring back evidence.

I began cleaning the beach, hauling away weathered and misshapen plastic debris – known and unknown objects, hidden parts of a world of things I had never seen before, and enormous whalelike colored entanglements of nets and ropes.

Three large plastic art installations, the central one a cornucopia spilling plastic objects onto the floor.
‘Bounty Pilfered’ (center), ‘Newer Laocoön’ (left) and ‘Threnody’ (right). All made of ocean plastic from the Atlantic, Pacific and Gulf of Mexico, installed at the Baker Museum in Naples, Fla., 2022. Pam Longobardi, CC BY-ND

I returned to that site again and again, gathering material evidence to study its volume and how it had been deposited, trying to understand the immensity it represented. In 2006, I formed the Drifters Project, a collaborative global entity to highlight these vagrant, translocational plastics and recruit others to investigate and mitigate ocean plastics’ impact.

My new book, “Ocean Gleaning,” tracks 17 years of my art and research around the world through the Drifters Project. It reveals specimens of striking artifacts harvested from the sea – objects that once were utilitarian, but have been changed by their oceanic voyages and come back as messages from the ocean.

Array of plastic objects, including toys, action figures and fragments of larger objects.
‘Drifters Objects,’ a tiny sample of the plastic artifacts Pam Longobardi has collected from beaches worldwide. Pam Longobardi, CC BY-ND

Living in a plastic age

I grew up in what some now deem the age of plastic. Though it’s not the only modern material invention, plastic has had the most unforeseen consequences.

My father was a biochemist at the chemical company Union Carbide when I was a child in New Jersey. He played golf with an actor who portrayed “The Man from Glad,” a Get Smart-styled agent who rescued flustered housewives in TV commercials from inferior brands of plastic wrap that snarled and tangled. My father brought home souvenir pins of Union Carbide’s hexagonal logo, based on the carbon molecule, and figurine pencil holders of “TERGIE,” the company’s blobby turquoise mascot.

On the 2013 Gyre Expedition, Pam Longobardi traveled with a team of scientists, artists and policymakers to investigate and remove tons of oceanic plastic washing out of great gyres, or currents, in the Pacific Ocean, and make art from it.

Today I see plastic as a zombie material that haunts the ocean. It is made from petroleum, the decayed and transformed life forms of the past. Drifting at sea, it “lives” again as it gathers a biological slime of algae and protozoans, which become attachment sites for larger organisms.

When seabirds, fish and sea turtles mistake this living encrustation for food and eat it, plastic and all, the chemical load lives on in their digestive tracts. Their body tissues absorb chemicals from the plastic, which remain undigested in their stomachs, often ultimately killing them.

Two piles of tiny particles of virtually identical sizes.
Plastic ‘nurdles,’ (left), tiny pellets that serve as raw materials for manufacturing plastic products, and herring roe, or eggs (right). These visually analogous forms exemplify how fish can mistake plastic for food. Pam Longobardi, CC BY-ND

The forensics of plastic

I see plastic objects as the cultural archaeology of our time – relics of global late-capitalist consumer society that mirror our desires, wishes, hubris and ingenuity. They become transformed as they leave the quotidian world and collide with nature. By regurgitating them ashore or jamming them into sea caves, the ocean is communicating with us through materials of our own making. Some seem eerily familiar; others are totally alien.

Two views of a degraded arm from a plastic doll, found on Playa Jaco in Costa Rica.
A degraded plastic doll arm, from the series ‘Evidence of Crimes.’ Pam Longobardi, CC BY-ND

A person engaging in ocean gleaning acts as a detective and a beacon, hunting for the forensics of this crime against the natural world and shining the light of interrogation on it. By searching for ocean plastic in a state of open receptiveness, a gleaner like me can find symbols of pop culture, religion, war, humor, irony and sorrow.

A rolling landscape covered with thousands of life vests.
‘Division Line,’ 2016. This photograph shows the ‘life-jacket cemetary’ in Lesvos, Greece. Traumatized asylum-seekers and migrants arriving by boat from Türkiye leave the life vests on shore as they stagger inland. Most of the waste is plastic. © Pam Longobardi, CC BY-ND

In keeping with the drifting journeys of these material artifacts, I prefer using them in a transitive form as installations. All of these works can be dismantled and reconfigured, although plastic materials are nearly impossible to recycle. I display some objects as specimens on steel pins, and wire others together to form large-scale sculptures.

A plastic bottle cap inscribed 'Endless' and a photograph of a beach littered with plastic objects.
From the series ‘Prophetic Objects,’ a plastic cap from a Greek manufacturer of cleaning products, found on the Greek island of Kefalonia. Pam Longobardi, CC BY-ND

I am interested in ocean plastic in particular because of what it reveals about us as humans in a global culture, and about the ocean as a cultural space and a giant dynamic engine of life and change. Because ocean plastic visibly shows nature’s attempts to reabsorb and regurgitate it, it has profound stories to tell.

A large sculpted anchor in the center of an art gallery, with ties to life preservers mounted on the ceiling.
‘Albatross’ and ‘Hope Floats,’ 2017. Recovered ocean plastic, survival rescue blankets, life vest straps and steel. Pam Longobardi, CC BY-ND

I believe humankind is at a crossroads with regards to the future. The ocean is asking us to pay attention. Paying attention is an act of giving, and in the case of plastic pollution, it is also an act of taking: Taking plastic out of your daily life. Taking plastic out of the environment. And taking, and spreading, the message that the ocean is laying out before our eyes.

Pam Longobardi, Regents’ Professor of Art and Design, Georgia State University

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

ooOOoo

Pam at one point describes the ocean plastic”… because of what it reveals about us as humans in a global culture, and about the ocean as a cultural space and a giant dynamic engine of life and change …”. It raises questions that I can only ponder the answer. Ultimately, are there too many inhabitants on this planet? What does the next generation think? Is there an answer?

Happy Endings!

All we all want is more good news than the other variety!

My sub-heading offers a great introduction to this recent essay over on The Conversation site. Republished within the terms of that site.

I don’t need to waffle on!

You all have a wonderful weekend.

ooOOoo

Will optimistic stories get people to care about nature?

By    David H. Smith Conservation Research Fellow, Georgia State University

May 7, 2017

Nature doesn’t make the news often these days. When it does, the story usually revolves around wildlife on the brink, record-setting climate extremes or ruined landscapes. However, that is not the whole story. There is also good news, but it often receives little attention.

It is easy to see how bleak accounts of the state of the planet can overwhelm people and make them feel hopeless. What is the point of even trying if the world is going down the drain anyway?

To muster public and political support on a scale that matches our environmental challenges, research shows that negative messaging is not the most effective way forward. As a conservation scientist and social marketer, I believe that to make the environment a mainstream concern, conservation discussions should focus less on difficulties. Instead we should highlight the growing list of examples where conservation efforts have benefited species, ecosystems and people living alongside them.

People’s Climate March, New York, New York, Sept. 21, 2014. CIFOR/Flickr, CC BY-NC-ND

The power of positive messages

This question is not new. Professionals in many fields have to consider how to frame their messages to maximize their impact. For example, public health agencies can make positive recommendations that emphasize benefits of being disease-free, or use negative messages that focus on the consequences of disease. A 2008 meta-analysis of 60 health communication studies concluded that messages focused on loss were less likely to be effective than positive messages.

Another study examined ads designed to persuade income support recipients to report their incomes. It concluded that messages focused on fear, shame or guilt could generate emotional backlash, in which people rationalized decisions to protect themselves from feeling ashamed of their behavior. This approach also caused emotional saturation that led people to “switch off” from the message because of its negativity.

Environmental advocates also confront this challenge. Much discussion has centered on the issue of climate change, where a number of scholars and advocates assert that doom-and-gloom messaging has not been effective. Yet until recently, we have not asked the same question about how we frame nature conservation.

Lost and found species

Today a growing number of scholars and activists are working to create a positive vision for protecting wildlife and wild places. One key effort started in 2014 with the launch of a marine conservation movement called Ocean Optimism, which works to “create a new narrative of hope for our oceans,” and by doing so, to help move towards “a sustainable future for our seas.”

In April 2017 the Earth Optimism Summit, organized by the Smithsonian Institution, brought together environmentalists, scientists, industry and the media to shift the global conservation movements focus away from problems and toward solutions. What started as a single event in Washington, D.C. soon turned into a truly global movement, with about 30 sister events in countries including Colombia, New Zealand and Hong Kong.

Lost & Found – Author provided

This effort has kick-started a range of initiatives that are all about communicating conservation bright spots to as many people as possible. One, which I co-founded, is the Lost & Found project, sponsored by the Society for Conservation Biology and the British Ecological Society. This online storytelling initiative focuses on a particularly inspiring kind of good news: rediscovering species that once were thought to be long extinct. After all, what can be more rousing than recovering something unique that you thought was lost forever?

Every year numerous species thought to have disappeared are rediscovered. Over the past century more than 300 species have been rediscovered, mostly in the tropics. On average, these species were missing for about 60 years before being rediscovered. Most rediscovered species have restricted ranges and small populations, which means they are usually highly threatened.

Lost & Found – Author provided

Our goal is not only to tell good stories, but also to showcase the dedication and determination of adventurers who lead these improbable quests and rewrite the history of species they care deeply about. While not every reader may be interested in a red-crested tree rat or a golden-fronted bower bird, all humans are curious about other people.

Lost & Found is making content available in various formats, including text, comics and soon, video animations. This helps make the stories more accessible to people who are not instinctively inclined to read about nature. Currently we have 13 stories freely available online that feature diverse species, from squirrels and toads to bats and birds. They cover a wide geographic range, from Latin America and Oceania to North America and Southeast Asia.

The response has been tremendously positive. More than 1,000 people from over 50 countries visited the website in its first 10 days. Some of our more popular stories, such as the Bulmer’s Fruit Bat and the Cave Splayfoot Salamander, are animals that would commonly not be considered particularly charismatic.

Getting these inspirational rediscoveries into the hands of as many people as possible is a first step toward creating a more positive vision for Earth’s future. The timeless principles of storytelling seem like the right place to start. After all, who doesn’t love a happy ending?

ooOOoo

Did you note the name of that website!!

Lost & Found. Go visit it and enjoy these wonderful happy endings!