Q: Since every day one hears new breakthroughs in cloning animals, how long will it be before we are able to close humans? --Danielle Ippolito, Columbia, South Carolina

Dr. Kenneth Roux, FSU biologist, replies:
   Technically, if one really wanted to, we could probably clone humans now. It night take a few years to work out the bugs since each species (including humans) is slightly different reproductively and developmentally. The real question is why would anyone want to do such a thing. There is no obvious scientific reason to do so. It is really a social question. There is nothing inherently bad about a clone. Identical twins are born all the time and they are natural clones. But since the idea seems to upset a lot of people and there is no compelling benefit, most scientists would support a ban on human cloning.

Q: Is there a consensus among physicists that every element that can be discovered already has been? --Robert A. Smith, St. Petersburg, Florida

Dr. Anthony Frawley, FSU physicist, replies:
   Uranium (element 92, meaning it has 92 protons) is the heaviest naturally occurring element. Until the Manhattan project, it was the heaviest element known. Since then, nuclear physicists and nuclear chemists have been synthesizing heavier and heavier elements in nuclear reactions. The heaviest element that has been observed in the laboratory so far is element 110. While the lighter synthetic elements (such as plutonium, element 94) can have lifetimes measured in tens to thousands of years, the very heavy elements typically have lifetimes measured in milliseconds before they undergo radioactive decay into lighter elements. It is expected that heavier elements will be observed in the future, as techniques for producing and detecting them are improved.

Q: Whatever happened to the space-plane idea that once was touted as being a cost-effective alternative to the space shuttle? --Carl Abstein, Boca Raton, Florida

Dr. Yulu Krothapali, mechanical engineer, replies:
   There are several programs underway to replace the shuttle. The most notable one that shows some promise is the X-33 space plane being built by Boeing. Lockheed Martin also is in the NASA program with plans to develop a replacement vehicle for space shuttle. At present, the X-33 is behind schedule for testing due to engine problems at Boeing's Rocketdyne Division.

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