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Copyright 2003, all rights reserved

No hummer hitchhikers, space pictures show unnatural color, strange baby names

Q: When hummingbirds fly south do they hitch rides on the backs of geese? — Bailey, Maryland

Canadian geese taking-off (no hitch-hikers) [Wyman Meinzer, US Fish and Wildlife Service]

A: It’s a nice picture but untrue. It’s hard to imagine a bird as feisty as a hummer clinging to a goose back. Hummingbirds and geese dwell in different ecosystems, migrate at different times, and fly to different places. Hummers don’t hitchhike.

However, a hummingbird could teach a goose about long-distances. Take the Rufus Hummingbird, for example. She flies as much as 12,000 miles (19,300 km) round trip — from the jungles of the Yucatan in Mexico through high mountains to Alaska and back. The Canadian goose travels at most a piddling 2,000 miles (3,200 km) a year.

Space pictures show unnatural color

Q: I have heard that all of NASA’s deep-space images are colorized because the long exposure times required for this type of imaging results in a black and white image. Is this true? Do the experts think that space phenomena, such as nebulas, are truly as colorful and beautiful as they are portrayed in science fiction movies? — Yale, West Lafayette, Indiana

Cat’s Eye Nebula. A dying star’s blue “eye” peers out from a surrounding cloud of ejected gasses. Enhanced image. [NASA/STScI ]

A: It is true that NASA’s deep-space images are not color images in the sense of a normal analog camera. The Hubble Space Telescope (HST), for example, measures how the sky’s radiation varies in lightness and darkness. It records numbers (like a digital camera) corresponding to brightness detected by each of its sensors. It takes a black and white picture. But what about the nebulae? Unfortunately, their natural color is not colorful.

Let’s clamber into a spacecraft and zoom off to the nearest nebula. Never mind how long it takes — this is a "thought experiment". We peer into the distance and finally spot the nebula. It looks grayish green. We close on the nebula to no avail. Still drab.

"Most nebulae look grey or green to the unaided eye looking through a telescope and even the largest telescopes show only faint colours," says Robert Massey, astronomer at the Royal Greenwich Observatory near London. "Using CCDs (like in a digital camera) or photographic film will show colours on long exposures."

Closer doesn’t matter. "If the nebula is too faint to see color, getting closer does not make it brighter or make color suddenly visible," says Jerry Lodriguss, astrophotographer.

The gas clouds are huge objects in the sky. The nebula’s light spreads out more as we approach it, says Massey. The amount of light increases but so does the size. Net result: nebulae appear bigger but still look "ghostly".

Hubble can render natural (if dim) colors by applying filters. The colors are not "colorized" but as natural as the colors you see on your TV screen. We take such pictures with the HST the same way we produce color video images — with filters. First, we slap a red filter (similar to a red-colored glass) over the detectors and record that picture. We repeat, recording the same scene with next a green filter and finally a blue filter — the three primary colors. We have three black and white pictures, each depicting the scene with each of the primary colors isolated. We combine the three black and white images into one and — voilB! — natural (if dull) color. NASA (or the science fiction producer, or both) then computer enhances the image to make it more colorful and beautiful.

"Hardly any of the Hubble pictures are ‘natural’ color," says Lodriguss. "The Mars shots, maybe. Virtually none of the nebulae pictures. The vast majority of astronomical scenes that you see in movies, though, are not from real images or objects. They are artistic creations of fiction — for example, the planet in the remake of the movie Solaris."

"As for the appearance of astronomical objects in science fiction movies, some are realistic and others are exaggerated," says Fred Espenak, astrophotographer at NASA.

Further Surfing:

Hubble Heritage Project: How heritage images are made from HST data

Hubble Site: The meaning of color in Hubble images

Strange baby names

Q: My son is doing a general knowledge test and we are struggling to find the answers for three questions: What are a young hare, a young falcon, and a young owl called? — Amanda, Harare, Zimbabwe

Eyases (aka nestling falcons) [City of New York Environmental Protection Agency]

A: A young hare (especially one less than a year old) is called a "leveret", of all things. The word comes from the Latin word for hare, lepus. Even stranger, baby falcons (particularly those to be trained for falconry) are eyases. More predictably, a young owl is an owlet.

Further Surfing:

Peregrine Falcon Watch, spring 2003: Falcon Facts

(Answered Oct. 10, 2003)