Welcome to the family, Pluto


Tanya Hill, Museum Victoria

What an amazing time for space exploration. The picture of the solar system from my childhood is now complete, as seen in this great family portrait produced by Ben Gross, a research fellow at the Chemical Heritage Foundation, and distributed via twitter.

I love this image because it shows each world in close-up, using some of the latest pictures from space exploration. As we celebrate seeing Pluto for the first time, it’s remarkable to think that this completes a 50 year task.

It has been NASA that has provided the first close-up views of all these worlds. Here’s the rundown:

  • Mercury: Mariner 10 (1973)
  • Venus: Mariner 2 (1962)
  • Mars: Mariner 4 (1965)
  • Jupiter: Pioneer 10 (1973)
  • Saturn: Pioneer 11 (1979)
  • Uranus: Voyager 2 (1985)
  • Neptune: Voyager 2 (1989) and
  • Pluto: New Horizons (2015)

But science never stays still. When New Horizons left Earth in January 2006, Pluto was a planet. Later that year an important reassessment was made of the Solar System and Pluto became the first of the dwarf planets.

The ‘Not-Planets’

The Planetary Society’s Senior Editor, Emily Lakdawalla, has teamed together the ‘Not-Planets’. These are the close-up views, shown to scale, that have been captured of the largest moons, asteroids and dwarf planets.


Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other data: NASA/JPL/JHUAPL/SwRI/UCLA/MPS/IDA. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

It clearly shows that there are many diverse and interesting worlds to explore beyond the eight planets of our solar system.

New Horizons is the first spacecraft to start exploring the Kuiper Belt, an icy realm of objects orbiting 5 billion kilometres or more beyond the sun. It’s the chance to observe a dwarf planet, something distinct from the terrestrial planets and the gas giants.

It was in 1992 that astronomers discovered Pluto was not alone. The first Kuiper Belt Object, designated 1992 QB1, is a 100-kilometre sized object that orbits well beyond Pluto.

Now more than 1,000 objects have been detected in this realm, and the belt likely contains many more. Most are small compared to Pluto, but there are some stand-outs such as Quaoar, and the dwarf planets Eris, Makemake and Haumea.

Don’t forget to phone home

The suspense of the mission has certainly been high. To maximise the amount of data that New Horizons could collect, the spacecraft did not communicate with Earth for the duration of the flyby. As described by Mission Operations Manager Alice Bowman, it was the moment when you let your child free.

The team had prepared New Horizons, told it what work needed to be done and in that radio silence they had to trust that all would go to plan.

Just before 11am today (AEST), New Horizons checked in – showing it to be the perfect child to the relief of its many anxious “parents”. It was only a brief phone home, but in that short time the scientists confirmed that all telemetry was spot-on, the spacecraft followed the path that had been set for it and there were no error messages recorded on any of the systems.

No data was transferred in that brief connection, but it was established that the main computer system, which records all the data collected by the spacecraft, showed the expected number of segments had been used. In other words, data had been collected.

We will soon see Pluto and Charon in even higher resolution. Their geology will be mapped, the surface compositions and temperatures will be measured, atmospheres will be probed and new discoveries will be made.

A love note from Pluto

It’s also been wonderful to see the public become so enthralled with the latest image from Pluto. Humans are incredibly good at spotting patterns and it seems that Pluto wears his heart on his sleeve for us.

I’m also equally intrigued to discover that the smooth part of Pluto’s heart is made of carbon monoxide ice. This was already known from ground-based observations, except never before seen in such detail. It’s reassuring to have a good match between the old and new data.

But look again … is it a heart or something entirely different stealing the show?

The Conversation

Tanya Hill is Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy) at Museum Victoria.

This article was originally published on The Conversation.
Read the original article.

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NASA: LATEST ON ‘TENTH PLANET’


On the 8th January 2005, scientists discovered that an object captured in time lapse images on the 21st October 2003 was in fact a tenth planet in our solar system while studying the images. The planet was known as 2003UB313 (Xena) and was photographed using the Samuel Oschin Telescope at the Palomar Observatory near San Diego, California. The tenth planet is now known as Eris, after the Greek goddess of discord and strife. Eris is thought to be a dwarf planet and to be slightly larger than Pluto (confirmed by the Hubble Space Telescope) at about 2400 km (1422 miles) in diameter.

On the outer edge of the solar system is a collection of objects (possibly 70 000) known as the Kuiper Belt (Kuiper Belt Objects – KBO). Most of these KBO are relatively small and some have names such as Sedna, Quaoar, Ixion, Varuna and Chaos.

Eris is thought to be about 97 times the distance from the Earth to the Sun (Pluto is 30 times the distance of the Earth to the Sun) – which means it is a very long way away from Earth (about 10 billion miles from Earth).

However, not all agree that Eris is a planet, preferring to call it a KBO. These same scientists generally regard Pluto as a KBO as well. Pluto is smaller than our moon and has its own moon which is called Charon.

In fact the International Astronomical Union (IAU) now recognizes both Pluto and Eris (along with another object known as MakeMake) as Plutoids. The IAU has assumed this role since 1919 and technically Pluto and Eris can no longer be considered planets.

Eris is the farthest known object in the solar system and is the third brightest of the objects in the Kuiper Belt and appears to be grey in colour. It is thought that there may be a methane frost covering the surface of the planet. It is the largest dwarf planet.

It is believed that Eris takes some 557 years to orbit the sun. It has one known moon known as Dysnomia (the name of the daughter of the goddess Eris). Dysnomia is about 175 km in diameter and is located about 37 370 km from Eris.

BELOW: Footage showing images related to Eris

For more information visit:

http://science.nasa.gov/headlines/y2005/29jul_planetx.htm

It is also interesting to note that there are some 327 moons in our solar system.

For more information visit:

http://solarsystem.nasa.gov/planets/index.cfm

http://www.iau.org/public_press/news/release/iau0804/

http://planetarynames.wr.usgs.gov/append7.html

Beyond our own solar system there are 319 known extrasolar planets – planets that orbit other stars (other than our Sun).

For more information visit:

http://planetquest.jpl.nasa.gov/atlas/atlas_search.cfm

http://exoplanet.eu/ (Extrasolar Planets Encyclopaedia)