Featured Research

from universities, journals, and other organizations

NASA Space Telescope Gives Scientists Depth Perception

Date:
June 1, 2007
Source:
NASA Jet Propulsion Laboratory
Summary:
Astronomers now have a new "eye" for determining the distance to certain mysterious bodies in and around our Milky Way galaxy. By taking advantage of the unique position of NASA's Spitzer's Space Telescope millions of miles from Earth, and a depth-perceiving trick called parallax, they were able to pin down the most probable location of one such object.

This artist's concept illustrates how Spitzer and a depth-perceiving trick called parallax allowed astronomers to determine the distance to an invisible Milky Way object called OGLE-2005-SMC-001. In this image, different views from both Spitzer and telescopes on Earth are combined to give depth perception.
Credit: NASA/JPL-Caltech-ESA/Hubble and Digitized Sky Survey 2

Astronomers now have a new "eye" for determining the distance to certain mysterious bodies in and around our Milky Way galaxy. By taking advantage of the unique position of NASA's Spitzer's Space Telescope millions of miles from Earth, and a depth-perceiving trick called parallax, they were able to pin down the most probable location of one such object. The findings will ultimately help astronomers better understand the different components of our galaxy.

"Forty years ago a visionary astronomer named Dr. Sjur Refsdal theorized that dark bodies could be located using parallax and a space telescope," said Andrew Gould of Ohio State University, Columbus, Ohio, who led the project. "It is truly remarkable that we have been able to prove him right with this Spitzer observation."

Spitzer is the only telescope that orbits the sun behind Earth, and is the farthest telescope from us with the ability to study distant stars. Currently, Spitzer is about 40 million miles (70 million kilometers) away from Earth. It will continue to drift farther and farther away at a rate of about 10 million miles (15 million kilometers) per year.

This great distance gives astronomers a great advantage. They can use Spitzer in the same way that a human brain uses two eyes to tell how far away objects are, a principle called parallax. With two eyes, we have two perspectives, which our brains combine to give us depth perception. In space, Spitzer acts as one eye, while a ground-based telescope acts as the other. With two very wide cosmic eyes, astronomers can determine the location of bodies within and just outside our galaxy.

Gould and his team are the first to use Spitzer to perform this astronomical feat. Their goal was to determine whether a previously identified dark matter candidate, called a massive compact halo object, or "Macho," is within our galaxy and contributing to its overall weight.

Our galaxy is heavier than it looks, with at least 80 percent of its mass consisting of mysterious, invisible dark matter. A large fraction of this dark matter is the exotic kind, different from the ordinary matter that makes up the familiar world around us. The rest might be so-called machos, which are ordinary-matter dark bodies that lurk in our galaxy's halo, the region that sits above and below its spiral disk. They are thought to be a combination of black holes, very faint stars and isolated planets.

Several suspected machos have been discovered in the past through a technique called microlensing, in which the dark bodies' gravity causes light from a passing background star to bend and brighten. But astronomers do not know whether these candidates are indeed machos in the galaxy halo, or other, non-macho objects just outside the Milky Way in small satellite galaxies. By pinpointing the location of the candidates, astronomers will learn whether they are in the halo and thus machos. This information, in turn, will help them figure out how much machos contribute to the total mass of our galaxy.

OGLE-2005-SMC-001 is one such macho candidate. It was first discovered by Andrzej Udalski, of the Optical Gravitational Lens Experiment (OGLE), and Warsaw University Observatory, Warszawa, Poland. Udalski and colleagues noticed that the dark object was causing a passing, background star to brighten. Gould and his team quickly sprang to action, following up with Spitzer observations of the short-lived event.

The data from both telescopes, or "eyes," were then combined and modeled through a series of complicated equations. The results indicate with 95 percent probability that OGLE-2005-SMC-001 is dark matter in our galaxy's halo and therefore a part of its overall mass.

In addition, the data show that OGLE-2005-SMC-001 consists of two bodies circling around each other. Gould and colleagues think the objects could be a pair of black holes, a very rare sighting in our universe. However, there is a small chance this feature is actually just a regular pair of orbiting stars in a neighboring, satellite galaxy.

"It will be very exciting to locate and measure the masses of more dark objects in the future by applying this technique. And we might finally be able to unravel the mystery of machos," said Subo Dong of Ohio State University, whose paper on OGLE-2005-SMC-001 has been accepted for publication in Astrophysical Journal. Dong presented the results today at a press conference, at the 210th meeting of the American Astronomical Society in Honolulu, Hawaii.


Story Source:

The above story is based on materials provided by NASA Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA Jet Propulsion Laboratory. "NASA Space Telescope Gives Scientists Depth Perception." ScienceDaily. ScienceDaily, 1 June 2007. <www.sciencedaily.com/releases/2007/05/070531074621.htm>.
NASA Jet Propulsion Laboratory. (2007, June 1). NASA Space Telescope Gives Scientists Depth Perception. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2007/05/070531074621.htm
NASA Jet Propulsion Laboratory. "NASA Space Telescope Gives Scientists Depth Perception." ScienceDaily. www.sciencedaily.com/releases/2007/05/070531074621.htm (accessed July 29, 2014).

Share This




More Space & Time News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
NASA EDGE: OCO-2 Launch

NASA EDGE: OCO-2 Launch

NASA (July 25, 2014) NASA EDGE webcasts live from Vandenberg AFB for the launch of the Oribiting Carbon Observatory-2 (OCO) launch. Video provided by NASA
Powered by NewsLook.com
This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins