2019 Review: August 12th - August 18th
From publicized news about asteroids approaching 'uncomfortably close' to Earth, to billionaire entrepreneurs tweeting about unleashing thermonuclear weapons on Mars, this week was no short of excitement.
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Let's begin with the billionaire CEO of SpaceX and Tesla - Elon Musk. On August 16th at 9:32 AM (UTC), Musk tweeted "Nuke Mars!", which he then followed up with another tweet proclaiming "T-Shirt soon". This appears not to be a random shower thought for Musk, but rather a recurring strategy which - in his mind - could help terraform Mars. For instance, four years ago Musk went on the Late Night Show with Stephen Colbert, where he claimed that the 'fast way' to make the planet suitable for life without transparent dome habitats, would be dropping thermonuclear weapons on the planet's poles.
The idea goes that doing so would vaporize the ice caps, releasing water vapour and
carbon dioxide (both of which are greenhouse gases - and potent ones at that) which
would contribute to global warming on the Red Planet, raising the temperature to sufficient
degrees for an atmosphere to emerge which could support life.
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However, there are a few problems to this technique - not least of which is the fact that it
remains unclear whether the attempt would yield any positive results. As Space.com
mentions, a study published in Nature Astronomy by Bruce Jakosky and Christopher
Edwards in 2018 showed that there isn't sufficient carbon dioxide present on Mars to
provide the desired level of global warming. The scientists analysed data from over the past 20 years, collected by rovers and observational spacecrafts sent to Mars. Their aim was to achieve an understanding of just how much of carbon dioxide is present in the rocks and the ice caps. It turns out that even though it would be enough to thicken the atmosphere by three times that which it is now, that would still be a measly one-fiftieth of what is required.
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Adding to that is the danger that the operation would horrifically backfire, causing our once-aspired future home to descend into nuclear winter - where essentially dust and debris from the explosion is ejected into the atmosphere, blocking out the sun and further cooling the planet. This would be similar to the after-effects of the asteroid impact which is thought to have killed off the dinosaurs.
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Apart from the questionable logistics of the operation, there is also the ethical aspect that should be considered - do we have the right to quite literally nuke another planet? And if we do, could it pose a threat to any existing lifeforms on Mars - those that might have evolved to survive the environment which would otherwise be inhospitable to life as we know it on Earth?
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Regardless, one must admit that the idea does seem like it would be an awesome spectacle.
Back in March of 2015, NASA launched the Magnetosphere Multiscale Mission, a mission designed to study the Earth's magnetosphere using four identical spacecrafts which orbited the Earth.
Recently, scientists studied a fascinating phenomenon using the MMS. NASA wrote on its website: "MMS was in just the right spot to see one interplanetary shock as it rolled by."
'What's an interplanetary shock and what's it to us?', you ask? Well, they are a type of collisonless shocks - wherein the particles transfer their energy by employing use of electromagnetic fields rather than colliding with them. This matters because this phenomenon can be seen all throughout the universe - from black holes to distant stars and supernovae. By studying the shocks around the Earth and how they interact with Earth's own magnetic field, MMS seeks to understand shocks throughout the universe.
Interplanetary shocks within our solar system start at the Sun, which is continually ejecting streams of charged particles - collectively known as the solar flare. As explained by NASA, there are two types of solar winds - the slower streams and the faster streams. When a faster stream overtakes a slower stream, it creates a shock wave which then spreads throughout the solar system.
One thing has always seemed clear: It's hard to deny that black holes are some of the most fascinating cosmic objects. Fortunately for physicists, their physics is equally as wondrous - until we start to pull our hairs out trying to understand the singularity, where our current knowledge of physics breaks down. Black holes are one of the mysteries that are at the frontier of what we know.
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Digressions aside, recently the observations made - and published in a study - by Tuan Do and his colleagues, using the Keck telescopes on the summit of Mount Kea in Hawaii, flooded the astronomical news. The telescopes were pointed towards the supermassive black hole at the center of the Milky Way, known as Sagittarius A*. By observing the matter around the black hole (known as the accretion disk) and its relative brightness, we can calculate and deduce its activity - that is, how many astronomical bodies it is eating.
An artist's depiction of a black hole at the center of a galaxy.
(Image Credits: © NASA/JPL-Caltech)
On May 13th, Do tweeted that they had witnessed the black hole brighter than they had ever seen before in infrared. "The black hole is always variable, but this was the brightest we've seen in the infrared so far. It was probably even brighter before we started observing that night!" They had begun their observations when the extreme brightness had started to dim, suggesting that the black hole had already reached its peak brightness, which would have been even greater!
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Theories are abound as to what caused the otherwise docile black hole to flare up to 75 times its usual brightness, including one explanation that a star called S0-2 could have passed by it, influencing the way that gas fell into the black hole and thereby changing the light emitted. Other explanations suggest that a gas cloud could have been absorbed by Sgr A* (Sagittarius A*) which would have caused more radiation to be emitted. In order to verify which of their theories is correct, the scientists will have to collect and analyse more data from both the Keck Observatory and other telescopes.
(Image: SPACEX)
While we're on the subject of both ELon Musk and his ambitions for colonizing Mars, recently a twitter user asked him how much it would cost to build a civilization on Mars.
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According to the SpaceX CEO, the figure lies somewhere between 100 billion dollars to 10 trillion dollars. He tweeted: "Between $100B and $10T." Explaining the cost, he said that 100 billion dollars would be the absolute minimum, considering how much it costs to ship payloads to Mars.
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Elon Musk has been quite vocal about his plans to establish a colony on the Red Planet. In March, he estimated that the goal could be achieved if started within the next five years. While many scientific minds are skeptical about the goal being achieved before the end of the century, Musk remains adamant that a self-sustaining colony could be established by 2050. He then went on to tease an internet system on Mars based on Starlink, which is a a network of satellites currently being developed (for usage on Earth - for now) by SpaceX, designed to provide the entire globe with broadband internet.
And now for the main event. Perhaps it has caught your attention how vehemently astronomers have lately been screeching for more attention to be given to asteroids. That recent outburst is partly due to an unexpected encounter with a 100 meter-wide asteroid which has now been named '2019 OK'.
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The asteroid, discovered just a day before it came threateningly close, passed within 65,000 kilometers - and if that sounds like a lot, then perhaps it's worth mentioning that that's about one-fifth of the distance to the moon. The near miss occurred on the 25th of July.
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The European Space Agency (ESA) stated regarding the event: "The 100 m-wide asteroid dubbed '2019 OK' was detected just days before it passed Earth, although archival records from sky surveys show it had previously been observed but wasn't recognised as a near-Earth asteroid."
(Image: © Shutterstock)
A question naturally arises that if we knew of its existence, then why didn't we know it would whiz past tauntingly close to our precious home planet?
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ESA states: "Unfortunately, there is currently no single obvious reason, apart from its slow motion in the sky before close approach. 2019 OK also travels in a highly elliptical orbit, taking it from within the orbit of Venus to well beyond that of Mars. This means the time it spends near Earth and is detectable with current telescope capabilities is relatively short. ESA, NASA and other agencies and organisations around the globe – professional and amateur – discover new asteroids every day. This work constantly increases our understanding of the number, distribution and movement of orbiting rocky bodies. Asteroids the size of 2019 OK size are relatively common in the Solar System, but hit Earth on average only every 100 000 years. Travelling in a highly elliptical orbit that takes it within the orbit of Venus, this asteroid won't come close to Earth again for atleast 200 years."
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This just goes to show that asteroid encounters like the one 65 million years ago, while incredibly rare, are still a very real threat to civilisation as we know it.
That about wraps it up for this week. Between learning that building inter-planetary colonies would quite literally cost a fortune, to breathing a sigh of relief after knowing that humanity continues to evade natural catastrophe, and watching a time-lapse of Sagittarius A* increasing in brightness up to unprecedented levels, it has been quite a full week.
See you next Sunday!