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5 reasons future space travel should explore asteroids
While the world considers future trips to Mars, two astrophysicists make a case for exploring asteroids.
On the same day that the Earth survived an expected near-miss with asteroid 367943 Duende, Russian dashcams unexpectedly captured footage of a different asteroid as it slammed into the atmosphere, exploded, and injured more than 1,000 people.
That day in Chelyabinsk in February 2013 reminded the world that the Earth does not exist in a bubble.
Asteroids provide a direct connection between the Earth and interplanetary space. Craters such as the Barringer Crater in Arizona are a stark reminder. The dinosaurs died out due to a different impact not far away in the Gulf of Mexico. But elsewhere in the universe, asteroids may actually transport life between different planets.
1. They could kill us
We did not see the Chelyabinsk meteor coming until the Russian dashcams caught it. Fortunately, nobody died as a direct result of the explosion. Next time we may not be so lucky. Even for known asteroids, there's at least a very slim possibility that they may collide with Earth over the next few hundred years. There are currently six known asteroids with at least a 0.1% chance of impacting the Earth before the 23rd century.
And the same asteroid which would cause a few casualties by exploding over a forest could kill thousands by instead exploding over a large city.
2. They could contain water
Astronomers debate the origin of Earth's water, and whether it was delivered to our planet billions of years ago by comets and asteroids. NASA's Dawn space probe visited the largest known asteroid, Ceres, and detected water on its surface. In fact, NASA classifies Ceres as a former “ocean world", albeit one where the ocean of water and ammonia has since frozen and reacted with the silicate rocks to form mineral deposits which now pepper the landscape.
3. They reveal how the solar system formed
The surfaces of asteroids don't erode like rocks on Earth because asteroids lack atmospheres. That means craters on asteroids are better preserved over long timescales, and give evidence of impacts from the last four billion years which would have long since washed away on Earth. In this way, asteroids can act as time capsules for evidence of the ancient universe.
The further back you go in time the trickier it becomes, as asteroids change in the hundreds of millions of years after their formation, shifting their positions and suffering collisions.
4. They reveal how the solar system will die
More than six billion years from now, when the sun uses all of its hydrogen fuel, it will start to change, eventually becoming a white dwarf – the end state for most stars in the Milky Way galaxy. During this transformation, the sun will briefly enlarge enough to swallow Mercury, Venus and maybe Earth. But at least five of the sun's planets and many asteroids will survive this transformation.
The asteroids then play an important role, as they are "kicked" towards the white dwarf by the gravitational field of the surviving planets when the asteroids approach them too closely. We regularly observe the broken up remains of asteroids inside the atmospheres of other white dwarf stars, allowing us to determine the asteroids' chemical composition by performing an autopsy from afar.
This technique is the most direct way we can probe the chemical composition of planetary systems outside of our own. Asteroids in our own solar system might then provide the best means for future galactic civilisations to find out more about the planetary bodies orbiting our future sun, long after Earth is gone.
5. They could transport life
We know the destructive nature of an asteroid impact, but what if it could instead act as a means of escape? A large enough impact by an asteroid would impart enough energy to eject material from the planet's surface. If the planet is habitable, some of the ejected material could become a transportation vessel for hardy microorganisms, which could stand a chance of surviving the launch into space.
Of course, the launch is just the start of the overall adventure. To complete the hop from one planet to another, life must withstand the harsh conditions of space during its interplanetary voyage. Upon reaching its destination, it must survive entry to the new planet, including another surface impact. The wide range of planetary systems discovered by astronomers in recent years could help. Some of these are tightly packed with potentially habitable planets close together.
The TRAPPIST-1 system is just one example. This is a clutch of seven planets orbiting a star 12 times smaller than our own sun, a mere 39 light years away. All of the seven planets are roughly the same size as Earth and clustered fairly close together – meaning bacteria could feasibly hop between them if disturbed by an asteroid on a nearby planet. With favourable conditions in place on the destination planet, life could have a much better chance of surviving the journey than if a living organism was ejected from Earth and arrived on a different planet in our solar system.
The many hurdles involved in this interplanetary hop make an arduous battle for microorganisms looking for a new home. Nevertheless, the theory will continue to generate intrigue as astronomers uncover yet more weird and wonderful worlds shaped by the influence of asteroids. With each new world comes a greater understanding of the key role they play in shaping our universe.
- NASA's 10-year plan to handle Earth-threatening asteroids - Big Think ›
- Asteroid mining will make us incredibly wealthy. Or will it? - Big Think ›
- Space travel could create language unintelligible to people on Earth - Big Think ›
- What is earth alienation? Hannah Arendt on outer space - Big Think ›
What is human dignity? Here's a primer, told through 200 years of great essays, lectures, and novels.
- Human dignity means that each of our lives have an unimpeachable value simply because we are human, and therefore we are deserving of a baseline level of respect.
- That baseline requires more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose.
- We look at incredible writings from the last 200 years that illustrate the push for human dignity in regards to slavery, equality, communism, free speech and education.
The inherent worth of all human beings<p>Human dignity is the inherent worth of each individual human being. Recognizing human dignity means respecting human beings' special value—value that sets us apart from other animals; value that is intrinsic and cannot be lost.</p> <p>Liberalism—the broad political philosophy that organizes society around liberty, justice, and equality—is rooted in the idea of human dignity. Liberalism assumes each of our lives, plans, and preferences have some unimpeachable value, not because of any objective evaluation or contribution to a greater good, but simply because they belong to a human being. We are human, and therefore deserving of a baseline level of respect. </p> <p>Because so many of us take human dignity for granted—just a fact of our humanness—it's usually only when someone's dignity is ignored or violated that we feel compelled to talk about it. </p> <p>But human dignity means more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose—a freedom that can be hampered by restrictive social institutions or the tyranny of the majority. The liberal ideal of the good society is not just peaceful but also pluralistic: It is a society in which we respect others' right to think and live differently than we do.</p>
From the 19th century to today<p>With <a href="https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&content=human+dignity&corpus=26&smoothing=3&direct_url=t1%3B%2Chuman%20dignity%3B%2Cc0" target="_blank" rel="noopener noreferrer">Google Books Ngram Viewer</a>, we can chart mentions of human dignity from 1800-2019.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODU0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MTUwMzE4MX0.bu0D_0uQuyNLyJjfRESNhu7twkJ5nxu8pQtfa1w3hZs/img.png?width=980" id="7ef38" class="rm-shortcode" data-rm-shortcode-id="9974c7bef3812fcb36858f325889e3c6" data-rm-shortcode-name="rebelmouse-image" />
American novelist, writer, playwright, poet, essayist and civil rights activist James Baldwin at his home in Saint-Paul-de-Vence, southern France, on November 6, 1979.
Credit: Ralph Gatti/AFP via Getty Images
The future of dignity<p>Around the world, people are still working toward the full and equal recognition of human dignity. Every year, new speeches and writings help us understand what dignity is—not only what it looks like when dignity is violated but also what it looks like when dignity is honored. In his posthumous essay, Congressman Lewis wrote, "When historians pick up their pens to write the story of the 21st century, let them say that it was your generation who laid down the heavy burdens of hate at last and that peace finally triumphed over violence, aggression and war."</p> <p>The more we talk about human dignity, the better we understand it. And the sooner we can make progress toward a shared vision of peace, freedom, and mutual respect for all. </p>
With just a few strategical tweaks, the Nazis could have won one of World War II's most decisive battles.
- The Battle of Britain is widely recognized as one of the most significant battles that occurred during World War II. It marked the first major victory of the Allied forces and shifted the tide of the war.
- Historians, however, have long debated the deciding factor in the British victory and German defeat.
- A new mathematical model took into account numerous alternative tactics that the German's could have made and found that just two tweaks stood between them and victory over Britain.
Two strategic blunders<p>Now, historians and mathematicians from York St. John University have collaborated to produce <a href="http://www-users.york.ac.uk/~nm15/bootstrapBoB%20AAMS.docx" target="_blank">a statistical model (docx download)</a> capable of calculating what the likely outcomes of the Battle of Britain would have been had the circumstances been different. </p><p>Would the German war effort have fared better had they not bombed Britain at all? What if Hitler had begun his bombing campaign earlier, even by just a few weeks? What if they had focused their targets on RAF airfields for the entire course of the battle? Using a statistical technique called weighted bootstrapping, the researchers studied these and other alternatives.</p><p>"The weighted bootstrap technique allowed us to model alternative campaigns in which the Luftwaffe prolongs or contracts the different phases of the battle and varies its targets," said co-author Dr. Jaime Wood in a <a href="https://www.york.ac.uk/news-and-events/news/2020/research/mathematicians-battle-britain-what-if-scenarios/" target="_blank">statement</a>. Based on the different strategic decisions that the German forces could have made, the researchers' model enabled them to predict the likelihood that the events of a given day of fighting would or would not occur.</p><p>"The Luftwaffe would only have been able to make the necessary bases in France available to launch an air attack on Britain in June at the earliest, so our alternative campaign brings forward the air campaign by three weeks," continued Wood. "We tested the impact of this and the other counterfactuals by varying the probabilities with which we choose individual days."</p><p>Ultimately, two strategic tweaks shifted the odds significantly towards the Germans' favor. Had the German forces started their campaign earlier in the year and had they consistently targeted RAF airfields, an Allied victory would have been extremely unlikely.</p><p>Say the odds of a British victory in the real-world Battle of Britain stood at 50-50 (there's no real way of knowing what the actual odds are, so we'll just have to select an arbitrary figure). If this were the case, changing the start date of the campaign and focusing only on airfields would have reduced British chances at victory to just 10 percent. Even if a British victory stood at 98 percent, these changes would have cut them down to just 34 percent.</p>
A tool for understanding history<p>This technique, said co-author Niall Mackay, "demonstrates just how finely-balanced the outcomes of some of the biggest moments of history were. Even when we use the actual days' events of the battle, make a small change of timing or emphasis to the arrangement of those days and things might have turned out very differently."</p><p>The researchers also claimed that their technique could be applied to other uncertain historical events. "Weighted bootstrapping can provide a natural and intuitive tool for historians to investigate unrealized possibilities, informing historical controversies and debates," said Mackay.</p><p>Using this technique, researchers can evaluate other what-ifs and gain insight into how differently influential events could have turned out if only the slightest things had changed. For now, at least, we can all be thankful that Hitler underestimated Britain's grit.</p>
We’ve mapped a million previously undiscovered galaxies beyond the Milky Way. Take the virtual tour here.
See the most detailed survey of the southern sky ever carried out using radio waves.
Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way, in the most detailed survey of the southern sky ever carried out using radio waves.
A new study shows our planet is much closer to the supermassive black hole at the galaxy's center than previously estimated.
Credit: NAOJ<p><em>Arrows on this map show position and velocity data for the 224 objects utilized to model the Milky Way Galaxy. The solid black lines point to the positions of the spiral arms of the Galaxy. Colors reflect groups of objects that are part of the same arm, while the background is a simulation image.</em></p>
Apple sold its first iPod in 2001, and six years later it introduced the iPhone, which ushered in a new era of personal technology.