New Horizons is Now 50 Astronomical Units Away From the Sun

As the New Horizons spacecraft hurtles out towards interstellar space, it has now reached an historical milestone. On April 17, 2021, New Horizons passed 50 astronomical units, or 50 times Earth’s distance from the Sun. It is just the 5th spacecraft to reach that distance, joining the Voyagers 1 and 2 and the Pioneers 10 and 11.

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Oumuamua is Probably Very Similar to Pluto, Just From Another Star System

In 2017, the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) made history with the detection of a mysterious object called Oumuamua (Hawaiian for scout). Unlike countless other small objects that Pan-STARRS had detected before, Oumuamua seemed to originate from beyond the solar system. The first known interstellar object detected in the solar system, Oumuamua, with its odd trajectory, strange shape, and unusual acceleration, led to a flurry of activity in the astronomical community and an avalanche of wild claims of extraterrestrial space ships from various fringes of the media. A pair of papers published by Alan Jackson and Steven Desch of Arizona State University earlier this month reveals the best fit model for the identity of our extrasolar visitor. No, it isn’t aliens, but it’s pretty spectacular. Oumuamua seems to be a shard of a Pluto-like planet from another solar system!

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Sunrises Across the Solar System

Scientists have learned a lot about the atmospheres on various worlds in our Solar System simply from planetary sunrises or sunsets. Sunlight streaming through the haze of an atmosphere can be separated into its component colors to create spectra, just as prisms do with sunlight. From the spectra, astronomers can interpret the measurements of light to reveal the chemical makeup of an atmosphere.

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Pluto and Other Kuiper Belt Objects Started Out With Water Oceans, and Have Been Slowly Freezing Solid for Billions of Years

It seems unlikely that an ocean could persist on a world that never gets closer than 30 astronomical units from the Sun. But that’s the case with Pluto. Evidence shows that it has a sub-surface ocean between 100 to 180 km thick, at the boundary between the core and the mantle. Other Kuiper Belt Objects may be similar.

But time might be running out for these buried oceans, which will one day turn to ice.

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New Horizons is so Far From Earth That the Positions of the Stars Look a Little Different From its Perspective

In July of 2015, the New Horizons spacecraft made history when it became the first robotic explorer to conduct a flyby of Pluto. This was followed by another first, when the NASA mission conducted the first flyby of a Kuiper Belt Object (KBO) on December 31st, 2018 – which has since been named Arrokoth. Now, on the edge of the Solar System, New Horizons is still yielding some groundbreaking views of the cosmos.

For example, we here on Earth are used to thinking that the positions of the stars are “fixed”. In a sense, they are, since their positions and motions are relatively uniform when seen from our perspective. But a recent experiment conducted by the New Horizons team shows how familiar stars like Proxima Centauri and Wolf 359 (two of the closest stars in our neighbors) look different when viewed from the edge of the Solar System.

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NASA is Now Considering a Pluto Orbiter Mission

NASA’s New Horizons mission taught us a lot about Pluto, the ice dwarf planet. But the spacecraft sped past Pluto so quickly, we only got high-resolution images of one side of the planet, the so-called “encounter side.” New Horizons gave us a big leap in understanding, but in a way, it asked more questions than it answered.

The next step is clearly an orbiter, and now NASA is starting to seriously consider one.

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A Bunch of New Names for Pluto’s Surface Features Were Just Approved

Pluto is getting some new names. In the past, prior to the New Horizons mission, there wasn’t much to name. But now that that spacecraft has flew past Pluto and observed it up close, there’s some features that need naming.

Now the IAU (International Astronomical Union) has approved a new set of names for 14 of the dwarf planet’s surface features.

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