Tag: science

Using the images and data so far received from New Horizons, planetary scientists outline some of their tentative conclusions as well as speculate about what it means.

[Alan Stern, New Horizons’ principal investigator] says Pluto’s surface appears to be much less heavily cratered than its large moon, Charon—which implies that the surface has been paved over in some way. That smoothing process could come from internal heat that keeps rock and ice soft, or by the frosts that snow down and blanket the surface in fresh ice. “Either [Pluto’s] internal engine continues to run, and there are active processes that are taking place,” Stern says, “or those atmospheric processes are themselves covering up the geology, and covering up the craters.”

Jonathan Lunine, a planetary scientist at Cornell University, not on the New Horizons team, favors the latter explanation. His initial impression is that Pluto is far more cratered than Triton, the moon of Neptune that is about the same size as Pluto and is thought to be a captured Kuiper belt object. Triton has a famous “cantaloupe” terrain, thought to have formed as heat, driven by Saturn’s tidal pull, allowed molten blobs of ice to rise and overturn. Parts of Pluto’s rugged surface seem to be far more carved and cratered, Lunine says. “It’s telling me that [Pluto’s] crust was not heated and modified to the extent that it was on Triton.”

Above all, however, I like Lunine’s comment at the end of the article:

Lunine says the emerging diversity on Pluto—of both active atmospheric and geological processes—makes him disagree with the decision of International Astronomical Union to call Pluto a dwarf. “This really is a planet,” he says. He notes that electrons have a double definition as a particle and a wave. “Why can’t we call Pluto a planet and a Kuiper belt object?” he asks. “I think we have to think of it as both.”

Today’s cool image, on the right, is the last one New Horizons sent back to Earth before its July 14th close encounter. Be sure you click here to see the full resolution version. It is quite spectacular. It was taken from about 476,000 miles, about twice the distance to the Moon.

The quality of this image strongly suggests that all will go well with the encounter today. However,

Per the plan, the spacecraft currently is in data-gathering mode and not in contact with flight controllers at the Johns Hopkins University Applied Physical Laboratory (APL) in Laurel, Maryland. Scientists are waiting to find out whether New Horizons “phones home,” transmitting to Earth a series of status updates that indicate the spacecraft survived the flyby and is in good health. The “call” is expected shortly after 9 p.m. tonight.

So, at 9 pm (Eastern) we will hear from New Horizons on its status. Images and data from the encounter itself however will arrive over time, beginning tonight and continuing throughout the coming months.

Another cool image for Monday morning: As the spacecraft zooms towards its Tuesday fly-by, it continues to take images of Pluto, even as the planet rotates. For example, compare today’s image on the right with the one I posted yesterday. You can see some of the same features (the donut-like, crater-like feature is the most obvious), but their positions are different because of the planet’s six-day rotation.

Note also that the row of black spots along the equator show more details. Not unexpectedly, they are not as simple as the early fuzzy images suggested. Unfortunately, we will not get to see even more details, as these features will not be in view during the fly-by.

Update: See this link for a new image of Charon.

More and more to come!

Very cool image time! The New Horizons science team today released [link fixed] their best image yet of Pluto, taken on July 7 immediately following the spacecraft’s recovery from safe mode.

This view is centered roughly on the area that will be seen close-up during New Horizons’ July 14 closest approach. This side of Pluto is dominated by three broad regions of varying brightness. Most prominent are an elongated dark feature at the equator, informally known as “the whale,” and a large heart-shaped bright area measuring some 1,200 miles (2,000 kilometers) across on the right. Above those features is a polar region that is intermediate in brightness.

For the first time these features look like actual surface areas on a planet, not fuzzy blobs. We are still seeing Pluto like we saw all planets prior to the space age, but at least now we know what we are looking at.

Cool image time! The New Horizons science team today released their best global map of Pluto, as seen so far.

The center of the map shows the area that New Horizons will see close-up during the fly-by.

The elongated dark area informally known as “the whale,” along the equator on the left side of the map, is one of the darkest regions visible to New Horizons. It measures some 1,860 miles (3,000 kilometers) in length. Directly to the right of the whale’s “snout” is the brightest region visible on the planet, which is roughly 990 miles (1,600 kilometers) across. This may be a region where relatively fresh deposits of frost—perhaps including frozen methane, nitrogen and/or carbon monoxide—form a bright coating.

Continuing to the right, along the equator, we see the four mysterious dark spots that have so intrigued the world, each of which is hundreds of miles across. Meanwhile, the whale’s “tail,” at the left end of the dark feature, cradles a bright donut-shaped feature about 200 miles (350 kilometers) across. At first glance it resembles circular features seen elsewhere in the solar system, from impact craters to volcanoes. But scientists are holding off on making any interpretation of this and other features on Pluto until more detailed images are in hand.

Some of these features will not be resolved much clearer than this, as Pluto’s day is six Earth days long, and will thus not be visible any longer to the spacecraft during its last week approach. In addition, much of the southern hemisphere will also not be imaged at all, as the planet’s inclination puts much of that hemisphere out of view entirely.

Nonetheless, we will see a great deal that has never been seen before. Stay tuned!

The journal Nature has put together a nice graphic [pdf] summarizing New Horizons’ mission and its fly-by of Pluto next week. The key section shows that it is going to take a long time to get all the data back:

Engineers have pinpointed the issue — “a hard-to-detect timing flaw in the spacecraft command sequence” — that caused New Horizons to enter safe mode on Saturday.

Since they do not plan to upload any similar commands before the July 14th fly-by, they do not expect a repeat of this problem. Full science operations are expected to resume on July 7.

Engineers lost contact with New Horizons for an hour and twenty-one minutes on Saturday.

Engineers have since begun talking with the probe again, but NASA says it will take up to several days to get New Horizons back to normal. In the meantime, the US$700-million spacecraft is not recording science data. It is just 11 million kilometres from Pluto, and closing in fast.

Communication issues are exacerbated by the fact that it takes four and a half hours to send a signal, traveling at light speed, across the nearly 4.8 billion kilometres to the spacecraft — and four and a half hours back. In that elapsed time, the Earth has rotated so much that mission controllers must switch from one to another of the three deep-space antennas that communicate with spacecraft: in Goldstone, California; Canberra; and Madrid.