Robotic origami

You know, of the paper crane variety. This one is done by the da Vinci Surgical System rom the Department of Telesurgery and Geomedicine, Kanazawa University, Japan.

How fast

In response to a very good question ™ posed by one of my students, a response. First, the question:

Question

How fast do spaceships or probes or satellites go? How long would it take for them to reach the closest star? The center of the galaxy?

Answer

The Voyager space probes, launched in the late 1970s, went to visit Jupiter and would eventually travel outside of our solar system. It’s actually approaching the Oort Cloud, and the true boundary of the system, called the Heliopause.

Voyager is travelling at about 56 000 km/h [1]. A different source cites a maximum velocity of 62 856 km/h [2]. It’s hard, sometimes, to decipher all of the conflicting information. At any rate, it will reach Proxima Centauri in about 19 000 years. Yawn.

More recently, the New Horizons space probe left Earth at a speed of 58 016 km/h, which is also quite impressive. [3] After passing close by Jupiter, and using something called gravity assist, it was accelerated to a speed of 83,700 km/h. [4] Even more impressive.

However, that’s not the whole story. (Neither is this example, as you will soon see.) The Pioneer 10 probe, sent out in 1972, was also accelerated by Jupiter. It reached a speed of 173 000 km/h. Faster yet.[5]

But there is… another. Launched in the mid 1970s by Germany (and the US), Helios was sent to orbit the Sun. Being accelerated by a mass that’s ten times that of Jupiter means a bit of a boost. Up to 240 000 km/h [6] (wikipedia says 252,792 km/h, but with no sources).

That seems to be the record. And it would take about 4 500 years for it to reach Proxima Centauri. If it were pointed towards there, that is.

What’s Dextre doing?

Your daily gratuitous Dextre (from APoD):

What’s the world’s most complex space robot doing up there? Last week, Dextre was imaged moving atop the Destiny Laboratory Module of the International Space Station (ISS), completing tasks prior to the deployment of Japan’s Kibo pressurized science laboratory. Dextre, short for the Canadian-built Special Purpose Dextrous Manipulator, has arms three meters in length and can attach power tools as fingers. Behind Dextre is the blackness of space, while Earth looms over Dextre’s head. The Kibo laboratory segment being deployed during space shuttle Discovery’s trip to the ISS can be pressurized and contains racks of scientific experiment that will be used to explore many things, including how plants brace themselves against gravity, and how water might be inhibited from freezing in cells under microgravity.

We are here (deux)

Terra and Luna, from Mars. From the same HiRISE camera that took photos of Phoenix on Mars’ surface. This time, looking back on us.

A bigger photo is over there. From the mission Website:

At the time the image was taken, Earth was 142 million kilometers (88 million miles) from Mars, giving the HiRISE image a scale of 142 kilometers (88 miles) per pixel, an Earth diameter of about 90 pixels and a moon diameter of 24 pixels. The phase angle is 98 degrees, which means that less than half of the disk of the Earth and the disk of the moon have direct illumination. We could image Earth and moon at full disk illumination only when they are on the opposite side of the sun from Mars, but then the range would be much greater and the image would show less detail.

We are here

We live in the Milky Way galaxy, a fairly typical open spiral galaxy galaxy (Type S, for you naming geeks out there). Those spirally bits spread out from the galactic core, and the whole thing is slowly (quickly) rotating, making one turn every 120 million years or so.

Well, we once thought there were four arms to the Milky Way; now we think there are only two. Regardez la photo:

We’re on a mini arm called the Orion Spur. Here’s a honking big image – you might be able to see better there.

From the MSNBC site that brought me the story (there’s more to read, so click through and take a look):

For decades, astronomers have pictured our galaxy as sporting four major, spiral arms, however new images effectively sever two appendages, revealing the Milky Way has just two major arms.

“We’re not proposing that they change the positions of the arms,” said Robert Benjamin of the University of Wisconsin, Whitewater. “What we’re proposing is a change in the emphasis of the arms.” Benjamin will present his team’s results today here at a meeting of the American Astronomical Society (AAS).

The Milky Way debuted as a spiral celebrity in 1951 when astronomical morphologist William Morgan of the Yerkes Observatory presented his results showing the galaxy’s three arms of hot stars, which he were then named Perseus, Orion and Sagittarius.

“Those were the first three arms of the spiral galaxy,” Benjamin told SPACE.com. “Actually, he got a standing ovation at the AAS meeting, which is something I’ve never seen.”

This is what 19th century astronomy William Herschel thought we looked like:

BTW – it’s -20C on Mars today. That’s a high temperature.