Tag Archives: ” NASA

Up close with Pluto

By Monica Grady, The Open University  
July, 2015

After a decade-long journey through our solar system, our New Horizons spacecraft made its closest approach to Pluto today, about 7,750 miles above the surface -- roughly the same distance from New York to Mumbai, India - making it the first-ever space mission to explore a world so far from Earth

After a decade-long journey through our solar system, our New Horizons spacecraft made its closest approach to Pluto today, about 7,750 miles above the surface — roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth. NASA

As I began typing this column, NASA’s New Horizon mission was on its final approach to its primary target, Pluto. By the time I finished composing my deathless prose, the main mission was over. And I’m not a slow writer.

Launched in January 2006, the spacecraft has travelled for nine and a half years for a flyby lasting only about 15 minutes. It doesn’t sound much of a reward for all the effort of designing and building the spacecraft – but for planetary scientists, the data coming back from the mission is pure gold.

For now all we can do is wait. Early in the morning on July 15, New Horizons is expected to phone home and confirm that the fly-by went well. Later that day the first high-resolution images should start trickle back to Earth – revealing what Pluto and its moon Charon actually look like up close. However, it will take nearly a year for all the data from the instruments aboard the spacecraft to come back.

But what is so exciting about Pluto? It isn’t even a planet anymore! When the New Horizons mission was conceived, Pluto stood (or rather, orbited) proudly as the ninth, and newest, planet in the Solar System. But eight months after New Horizons left Earth on its journey to Pluto, the International Astronomical Union downgraded Pluto from “planet” to “minor planet”.

Pluto’s change in status has, however, definitely not diminished the importance of the mission. Indeed, it has probably enhanced the scientific significance of the findings. Back when we thought Pluto was a planet, it was merely the last member of a series which represented a progression from the inner rocky and metallic bodies such as Mercury, through the gas and ice giants like Jupiter and Neptune, to Pluto – a small body of ice and rock.

But we now know that Pluto is not an isolated entity – it is the largest body in a huge family of primitive objects, many of which have their own moons. According to current models of how the solar system formed, there were once several hundred thousands of objects beyond Neptune, but Jupiter’s motion scattered most of them much further out from the Sun.

There are, however, still likely to be more such remaining bodies, known as Trans-Neptunian Objects, than the asteroids in the main belt between Mars and Jupiter. These objects are probably even more primitive in nature than some comets, which have been modified as they approach the Sun.

We already know that methane and ammonia ices are present on Pluto – but are there any higher hydrocarbons, or biologically interesting compounds such as amino acids? It will be interesting to see how analysis of the surface ices compare with results from the Rosetta mission or from the Dawn mission at Ceres. Can we draw any comparisons with the photo-chemistry on Saturn’s giant moon, Titan? Will Pluto demonstrate that trans-Neptunian objects are the most unchanged and unprocessed objects in the Solar System?

Previous images of Pluto have been poorly resolved – the best view by the Hubble Space Telescope is of a fuzzy grey blob (see image below). But over the past few weeks, we have been able to enjoy increasingly more detailed images taken by the New Horizons spacecraft on its approach to Pluto. For example, we’ve learned that the planet is slightly bigger than we thought. We have also seen features on the surface, including what are probably ice-caps.

Although the closest approach to Pluto will be over in a matter of minutes, the amount of data captured will be immense. It could help us answer a number of questions about Pluto – such as the distribution of different ices (water, ammonia, methane), the relationship between rock and ice and the presence of a thin atmosphere. The fly-by could also shed light on whether there are indeed craters on the body and whether there is any evidence of resurfacing.

Image of Pluto and its moon Charon. NASA

Image of Pluto and its moon Charon. NASA

There is no expectation that cryovolcanism or ice geysers will be observed on Pluto, it doesn’t have the same gravitational heat source derived from a giant companion such as the case for Jupiter’s moon Europa. But it is in a binary system with its almost equally-sized moon, Charon – so it may surprise us yet.

For me, one of the highlights of the coming months will be synthesis of three sets of data – from New Horizons on Pluto, Dawn on Ceres and Rosetta-Philae on comet 67P/Churyumov-Gerasimenko. This will give us real insight to comet-asteroid interrelationships, and the primitive material from which the Solar System was built.

Whatever comes from the fly-by, we already have enough fresh information about our far-distant neighbour to ensure it is no longer seen as an underworld, the underdog of our planetary system. It is not the last planet to be visited but it is the first trans-Neptunian object to be seen – and so becomes a member of a very exclusive club.

Creative Commons

The Conversation

Monica Grady is Professor of Planetary and Space Sciences at The Open University. This article was originally published on The Conversation. Read the original article.

Related on F&O: Our blog post,  Pluto: Notably quotable, includes recommended reading.




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Moon Eclipse


Graphic of the April 15 lunar eclipse, by NASA scientist Noah Petro. Image courtesy of NASA.

A full eclipse of the moon will occur overnight, visible in the Western hemisphere for three hours from late Monday April 14 (in western time zones) and early Tuesday April 15 (in the east).

The United States National Aeronautics and Space Administration (NASA) will stream a live feed of the eclipse, here, for some three hours starting at 2 a.m. EDT. The peak of the eclipse  — when the moon enters the Earth’s full shadow or umbra — will occur at 3:45 a.m., said NASA.

NASA’s animated productions of the eclipse, as seen from moon, are here.

An excerpt from the video below:

Like clockwork, the full Moon appears every month in our sky, a sight so familiar that we often take it for granted, but about twice a year, over the course of a few hours, the full Moon sports a decidedly different look. What causes this sudden change? A lunar eclipse occurs when the Moon passes through the Earth’s shadow, just as a solar eclipse occurs when part of the Earth passes through the Moon’s shadow. But the Moon circles the Earth every month as it cycles through its phases, lining up at both full Moon and new Moon. So why don’t eclipses happen twice a month? The reason is that the Moon’s orbit around the Earth is tilted relative to the Earth’s orbit around the Sun. Although the Earth and the Moon always cast long shadows, they rarely shade each other thanks to the Moon’s orbital tilt. But if that’s the case, why do eclipses happen at all? Throughout the year, the Moon’s orbital tilt remains fixed with respect to the stars, meaning that it changes with respect to the Sun. About twice a year, this puts the Moon in just the right position to pass through the Earth’s shadow, causing a lunar eclipse. As the Moon passes into the central part of the Earth’s shadow, called the umbra, it darkens dramatically. Once it’s entirely within the umbra, the Moon appears a dim red due to sunlight scattered through the Earth’s atmosphere. In fact, if you watched the eclipse from the surface of the Moon, you’d see the Sun set behind the entire Earth, bathing you in a warm red glow. Back home, you’ll have to stay up late to watch a lunar eclipse, but if you do you’ll see the Moon in rare form, and you’ll catch a brief glimpse of our own planet’s long shadow.


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Looking up

On Wednesday an American, a Russian and a Japanese will board a Soyuz spacecraft and blast up and out of earth’s atmosphere, to join six others in orbit on the International Space Station. For those of us left behind, stifled in our fug of petty squabbles and warmongering, it’s startling to remember that people can, sometimes, rise above polarized politics, zealotry, nationalism and government gridlock.

Cassini for F&O blog

Saturn: “Jewel of the Solar System.” Photo: NASA/JPL-Caltech/SSI/Cornell

The Soyuz launch from a Kazakhstan base can be watched online on NASA Television, or in New York, on a giant screen in Times Square, just after 11 p.m. EST.

Meanwhile check out this image of Saturn, right, from cameras aboard the Cassini-Huygens mission. The mission is a joint venture of America’s National Aeronautics and Space Administration, the European Space Agency and the Italian Space Agency. The imaging team that produced it includes scientists from the United States, the United Kingdom, France and Germany.

NASA calls this shot of Saturn with its rings a “portrait.” Will it join the canon of human art? Who knows. At least, it shows what humans can do when we stop butting heads and put them together.

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Not finished with Earth

Well, damn. Seems we’ll be stuck on this spinning rock in space a while longer: humanity’s best shot at escape died a heavenly death this week. NASA announced it can’t fix the broken Kepler Spacecraft, tasked with solving an earth-shaking question, “Are Earths in the habitable zone of stars like our sun common or rare?” 

Escape has been our thing for a while now. The Kepler mission (“A Search for Habitable Planets”) was just the latest. There was Icarus, of course. There are multiple religious or superstitious versions of an afterlife. There was the euphoria over the Age of Flight, illustrated in this comment by Jacques Alexandre César Charles, one of two balloonists on the first manned flight over Paris in 1783: “Nothing will ever quite equal that moment of total hilarity that filled my whole body at the moment of take-off. I felt we were flying away from the Earth and all its troubles for ever. It was not mere delight. It was a sort of physical ecstasy. My companion Monsieur Robert murmured to me – I’m finished with the Earth.”*

Earth will be finished with us even if we aren’t finished with her, Stephen Hawking warned three years ago. Other modern doomsayers, such as scientist James Lovelock of Gaia fame, have said humankind has already passed the point of no return, that in the 21st Century we are already too near to, and moving too fast toward, the precipice of existence to turn back. Hawking is a tad more optimistic: our future is in space he says, but we really should not have “all our eggs” in the one basket of earth. 

There is still a chance the Kepler mission will come through: data collected on the mission and yet to be analyzed may hold the answer, said Kepler’s science principal investigator in the press release.

In the meantime, perhaps we should clean up our joint? Give ourselves a chance of clinging to our rock for a while longer? And if you’re one of the religious extremists convinced an End Times is imminent, or a sci-fi fan who believes aliens will come to the rescue, good luck to you – but do mind your own business as the rest of us start keeping our house.
References and further reading:
* Page 161, Age of wonder by Richard Holmes.
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