What would happen if Earth was hit by a 500-km asteroid?

March 1, 2015

An amazing computer visualization by the Discovery Channel (reported here by IFL Science) shows the damage caused by an impact of a 500-km asteroid with our fragile Earth. Basically, many things would fry. An ocean of magma (melted rock) would be created. Hot debris would rain down thousands of kilometers from the impact site. School would probably be cancelled.

Be sure to also check out the link to the impact calculator mentioned at the end of the IFL Science post. It tells you what would happen in the event of collisions with different parameters, such as impactor size, velocity, composition, etc.

Discovery Channel

Discovery Channel


Lunar and Planetary Science Conference approaching

February 26, 2015

Only 20 more days till the Lunar and Planetary Science Conference (LPSC) begins! This is a venerable gathering of scientists who study the geology, geochemistry, and astrophysical aspects of solar system objects. It promises to be an exciting event to learn the latest in lunar research, hear about the latest results from the Mars Curiosity rover, and feast on the amazing science being delivered by the Rosetta space probe currently in orbit around a comet! I’ll be blogging from the Conference.

Credit: NASA/JPL

Credit: NASA/JPL


An opportunity to see bison up close and help in conservation efforts

April 10, 2014

I found this amazing project to study wildlife on the prairies of Northeastern Montana. They require volunteers to gather data and help build the largest protected wildlife area in the continental United States, making it larger than Yellowstone National Park!

More information here.

Credit: Dennis Linghor

Credit: Diane Hargreaves

Credit: Valerie Bruchon

 


Exploring rocky worlds

March 27, 2014

Our solar system is a wondrous place. Not much time goes by after one exciting discovery before we come across a new finding that surpasses the previous one in impact factor. That may well be what is in store for NASA’s Dawn mission to the asteroid belt, a space mission to, effectively, study our planetary origins.

Artist rendition of Dawn spacecraft's journey Credit: NASA/JPL-Caltech

Artist rendition of Dawn spacecraft’s journey
Credit: NASA/JPL-Caltech

The Dawn spacecraft “visited” the third largest member of the asteroid belt, called Vesta, in 2011 and 2012, and is now headed towards an encounter with the considerably larger Ceres in 2015. Despite being traditionally known as asteroids, the relatively large sizes of Vesta and Ceres create a bit of a headache for astronomers as to their exact designation (under the new definitions introduced by the International Astronomical Union that demoted Pluto from the planet club in 2006, Ceres is now termed a “dwarf planet”), and so there doesn’t seem to be an agreement among the astronomical community about what best to call them. Nevertheless, most experts agree that those two huge rocks are protoplanets, that is, precursors of what would otherwise have been one or more planets.

Ceres is an almost spherical body with a diameter of 974 kilometers; that’s about the size of Texas! Its mass alone comprises about one-third of the total mass of bodies in the asteroid belt. With the help of very precise calculations, planetary scientists have concluded that it contains a rocky core at its center, which in turn is surrounded by a mantle of water ice that could be up to 100 km thick. If this is true, then it would mean that Ceres contains more water than the amount of fresh water on Earth!

Size comparison of Earth, the Moon, and Ceres. Image: NASA

Size comparison of Earth, the Moon, and Ceres. Image: NASA

 

Ceres viewed with the Hubble Space Telescope. Image: NASA

Ceres viewed with the Hubble Space Telescope. Image: NASA

In fact, we might already have direct evidence of the presence of water on Ceres. An international team of astronomers recently discovered what could very well be a tenuous cloud of water vapor emanating from distinct sources on the surface of the dwarf planet. The observations were carried out with the Herschel space telescope, and they could point to either cryo-volcanic activity (meaning that volcanoes would erupt water instead of molten rocks) or comet-like sublimation of near-surface ice (sublimation is the transformation of ice directly into vapor). Which of these two mechanisms is the right one is something that Dawn might be able to answer in about a year’s time.

Credit: NASA/ESA/STScI

Credit: NASA/ESA/STScI

Vesta is slightly more irregular in shape than Ceres, and it has a mean diameter of 525 km. It contains very little water, and its south pole is marked by an enigmatic feature: an enormous crater almost as large as Vesta itself, with a diameter of 460 km and 13 km deep. There is no general consensus yet about what caused it, but some estimates suggest that a 42-km projectile, traveling at a whopping 5 km/s, might have been the culprit. Imagine what it would have been like to witness such an explosive event!

South pole of Vesta, imaged by the Dawn spacecraft. Credit: NASA.

South pole of Vesta, imaged by the Dawn spacecraft. Credit: NASA.

One of the most amazing outcomes of this collision is that it might have been responsible for sending pieces of Vesta our way, in the form of meteorites. This has been inferred from laboratory studies of a particular type of meteorites, called howardite-eucrite-diogenite, or HED for short, whose stony properties seem to match those of Vesta and its “family”, a group of smaller asteroids thought to have been expelled from the giant impact on Vesta’s south pole. I find it mind-blowing that we on Earth are able to hold in our hands fragments of material that was formed billions of years ago, when the solar system was still in its infancy…

The elevation on the south pole of Vesta (at the bottom of the image) is more than twice the height of Mount Everest. Credit: NASA/JPL-Caltech/ UCAL/MPS/DLR/IDA

One of the last images of Vesta taken by Dawn as it departed towards Ceres. Credit: NASA/JPL-Caltech/ UCAL/MPS/DLR/IDA

Perhaps in the not-too-distant future astronauts will be able to land on, and explore, Ceres and Vesta. The good thing about landing on bodies of that size is that you won’t need as much fuel to take off again, because they have less gravity than, say, the Earth or Mars. Could it be you who will walk on the surface of an asteroid for the first time?

 

 


NewSpace at the American Museum of National History

March 21, 2014

Last Wednesday, noted science communicator Neil deGrasse Tyson hosted the annual Isaac Asimov Memorial Debate at the American Museum of National History. The panelists included high executives from space companies, space organizations, and experts on space policy. The title of the debate was a concise “Selling Space”. Hopefully, it will become available on YouTube soon.

I share here a few conclusions that I drew from the many interesting points touched upon:

1. Access to space for ordinary citizens is still many years away. Even if the space tourism companies successfully pull their vehicles off the assembly line and into the launch pad (or runway), ticket prices will remain on the order of $100,000 for suborbital flights, and tens of millions for orbital and cis-lunar flights. On the upside, those same companies will be able to offer much lower prices for scientific research, compared to government-led missions.

2. There seems to be a disagreement between industry leaders and policy experts as to the inspirational value of space tourism to engage the public in space exploration. While some think that only government astronauts can inspire the public and younger generations, much like the early astronauts of the Mercury, Gemini and Apollo programs of the 1960s and 1970s, others are confident that space tourists can add a certain educational value to their multimillion-dollar “joyrides”, as one panelist put it. I see merit on both sides of the argument, but I think space companies can renew the excitement for space exploration if their missions include precisely that kind of focus, exploration.

3. Some people are nervous about the safety goals of the commercial space companies. It’s probably natural that during the emergence of such a “disruptive” industry as NewSpace (the umbrella term that refers to the different private enterprises whose aim is to transport people and cargo to low-Earth orbit and beyond) some fears may arise. However, I’m confident that safety milestones are foremost in designers’ minds.

Image credit: SpaceX

Image credit: SpaceX


The bold rescue mission that never was

March 3, 2014

My friend Eva Noyola pointed out a recent article that describes a hypothetical rescue mission that could have been implemented to save the astronauts on board space shuttle Columbia 11 years ago, according to Appendix D.13 of the Columbia Accident Investigation Board Report. The article is gripping in its rendition of the drama that would have unfolded had NASA decided to launch a rescue flight to bring the astronauts back to Earth. It seems, however, that such a complex operation would have been extremely difficult to accomplish given the time constraints. Nevertheless, it’s food for thought for future rescue missions.

caib_07

Image credit: NASA


The most vivid first lunar landing to date

October 28, 2013

I came across this magnificent website, built by an alumnus of the University of Texas at Austin, of the first lunar landing.

The website shows communications between Mission Control and the astronauts of Apollo 11 during the last several minutes before touchdown, as well as after. The transcripts are shown in real time, and they allow the user to understand what’s going on (if you are familiar with the technical jargon, that is!).

The website also features a pictorial representation of the Lunar Lander and its pitch angle, and video of the lunar surface as seen from one of the windows.

It’s the most realistic experience that I’ve found of that historic event!

The website is here:

http://www.firstmenonthemoon.com/


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