Winter 2016 - Volume 45, Number 1
Table of Contents
[19] Coloring the Universe, Travis Rector, Kimberly Kowal Arcand, and Megan Watzke
This customized excerpt is from a new book that offers an insider’s look at how spectacular images of deep space are made.
[27] The 2016 Transit of Mercury, Fred Espenak with Paul Deans
What it’s all about, when and where to look, and how to safely view the transit, particularly as a test run for observing the solar eclipse in 2017.
[33] Extrasolar Planets: The Saga Continues, Paul Deans
An occasional account of our ongoing discoveries of planets beyond the solar system, including a look into the birthplaces
of exoplanets.
[40] Astronomy in the News
New changes in Jupiter’s Great Red Spot, a possible new (ninth) planet in our solar system, and a supernova caught in the act. These are some of the discoveries that recently made news in the astronomical community.
Departments
[4] Perspectives, Paul Deans
The Sky Alight
[5] First Word, Linda Shore
Back to the Future with the ASP Catalog
[7] Annals of Astronomy, Clifford J. Cunningham
William Ludlam and the Transit of Venus
[8] Astronomer’s Notebook, Jennifer Birriel
Defining a Planet
[10] Planetary Perspectives, Emily Joseph
How to Acquire an Image of Titan
[11] Strange New Worlds, Space Telescope Science Institute
Most Earth-Like Worlds Have Yet to Be Born
[13] Armchair Astrophysics, Christopher Wanjek
A Gamma-Ray Powerhouse in a Galaxy Next Door
[14] Education Matters, Brian Kruse
Probing for Understanding
[16] Reaching Out, American Astronomical Society
AAS Nova: Astronomy Research Results for Everyone
[49] ASP Tidings
Call for Nominations for ASP’s 2016 Awards
[50] Sky Sights, Paul Deans
Spot Mercury at Dawn and Dusk
[53] Reflections, NASA
A High-Resolution Earthrise
Coloring the Universe
by Travis Rector, Kimberly Kowal Arcand, and Megan Watzke
If you’re reading this article, you probably love astronomy images. When looking at an image of, say, a galaxy, have you ever wondered “Is this real?” or maybe “Is this what it really looks like?”
The first question is easy to answer. Yes, everything you are seeing is real. Unless it is “space art,” these images are of real objects in outer space. They aren’t creations of a graphic artist’s imagination. But answering the second question is not as simple. How a telescope “sees” is radically different than how our eyes see. Telescopes give us super-human vision. In most cases they literally make the invisible visible.
To better understand what’s going on, it helps to know what a telescope does. Just as a pair of binoculars can make the upper-level seats in an arena almost as good as courtside, a telescope can make a distant object appear much closer. But a telescope does more than this. It doesn’t just magnify an object; it also amplifies it. It makes something faint appear much brighter.
The 2016 Transit of Mercury
by Fred Espenak with Paul Deans
The transit or passage of a planet across the disk of the Sun may be thought of as a special kind of eclipse. On Monday, May 9, 2016, Mercury will transit the Sun for the first time since 2006. The movement of a planet across the face of the Sun is a relatively rare occurrence. As seen from Earth, only transits of Mercury and Venus are possible. There are approximately 13 transits of Mercury each century. In comparison, transits of Venus occur in pairs with more than a century separating each pair.
Think of the transit of Mercury as an extremely miniature annular solar eclipse. This means the safety rules for observing an annular or partial eclipse of the Sun also apply to observing the Mercury transit. And the number one rule is: Never look directly at the Sun without using a safe solar filter.
Extrasolar Planets: The Saga continues
by Paul Deans
We’ve found planets beyond the solar system. Lots of them, in fact — currently more than 5,600 candidates and approaching 2,000 confirmed. Most have been discovered by the Kepler spacecraft, but many other telescopes and teams are now in the game.
Moving on past the simple realm of discoveries, what are we learning about these worlds beyond? Well, astronomers are getting a better handle on how exoplanets are born. They’re able to peer into the disks of gas and dust that surround certain stars to discern telltale structures produced by protoplanets. They’re also imaging protoplanetary systems and finding what appear to be planet-size bodies caught in the act of accreting.
Hubble’s Planetary Portrait Captures New Changes in Jupiter’s Great Red Spot
NASA/Goddard Spaceflight Center
Scientists using NASA’s Hubble Space Telescope have produced new maps of Jupiter – the first in a series of annual portraits of the solar system’s outer planets.
Collecting these yearly images — essentially the planetary version of annual school picture days for children — will help current and future scientists see how these giant worlds change over time. The observations are designed to capture a broad range of features, including winds, clouds, storms and atmospheric chemistry.
Already, the Jupiter images have revealed a rare wave just north of the planet’s equator and a unique filamentary feature in the core of the Great Red Spot not seen previously.
“Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on,” said Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This time is no exception.”
Simon and her colleagues produced two global maps of Jupiter from observations made using Hubble’s high-performance Wide Field Camera 3. The two maps represent nearly back-to-back rotations of the planet, making it possible to determine the speeds of Jupiter’s winds.
The new images confirm that the Great Red Spot continues to shrink and become more circular, as it has been doing for years. The long axis of this characteristic storm is about 150 miles (240 kilometers) shorter now than it was in 2014. Recently, the storm had been shrinking at a faster-than-usual rate, but the latest change is consistent with the long-term trend.
The Great Red Spot remains more orange than red these days, and its core, which typically has more intense color, is less distinct than it used to be.
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